From The University of Wisconsin-Madison Via “Science Alert (AU)” : “Entire Planets Made of Dark Matter May Exist. Here’s How We Can Find Them”

From The University of Wisconsin-Madison

Via

“Science Alert (AU)”

3.27.23
Michelle Starr

Artist’s impression of the hypothetical Solar System object Planet Nine. (Nagualdesign/Tomruen/Wikimedia Commons)

We may not have found many planetary systems like our own Solar System. Still, there’s one thing they do seem to have in common: They appear to be made out of good ol’ ordinary baryonic matter – you know, the stuff our planetary system is made of.

But what if there are planets out there that are made of other stuff: particles outside the Standard Model? What if there are planets made of the mysterious stuff we call dark matter?

No one can answer that question one way or another at least not with our current knowledge. But a team of scientists led by theoretical physicist Yang Bai of the University of Wisconsin-Madison wanted to know how these hypothetical planets would manifest – and if we could detect them if they’re real.

The short answer is yes, if certain conditions are met, and the researchers laid out why in a paper published on the preprint server arXiv.

There are a lot of outstanding mysteries in this Universe of ours, but one of the biggest has to be dark matter. We don’t know what dark matter is, and we don’t know what it looks like or what it’s made of. The only thing we know for sure is that the gravity in the Universe is in serious excess of the amount of baryonic matter.

Once you’ve accounted for every galaxy, every star, and every cloud of dust drifting silent and dark between the stars, there’s still way more gravity than there should be. We don’t know what’s responsible for it, but we call that mystery source dark matter, and there are several theoretical candidates that scientists are investigating.

Broadly, these candidates can be divided into two categories: single particles, and composites, including macroscopic blobs of dark matter, or Macros, that could have planet-scale masses. And, as Bai and his colleagues explain, “A macroscopic dark matter state with its mass and/or radius similar to those of a planet will behave as a dark exoplanet if it is bounded to a star system, even if the object’s underlying physics resembles something else entirely.”

Our current methods of detecting exoplanets are largely, currently, based on the effect an exoplanet has on the light of its host star. We can also use this information to measure the exoplanet’s properties.

An exoplanet passing between us and its star, a passage known as a transit, will cause the star’s light to dim a tiny bit.

Planet transit. NASA/Ames.

Astronomers can measure the depth of the dimming to calculate the radius of the exoplanet. Exoplanets also cause their stars to move a little bit, as the two move around a mutual center of gravity, detectable in changes in the wavelength of the star’s light. The amount of motion, called radial velocity, can be used to calculate the exoplanet’s mass.

Animation showing how radial velocity is measured. (Alysa Obertas/Wikimedia Commons, CC BY-SA 4.0)

With these measurements in hand, we can calculate the density of an exoplanet and thus determine how it is constructed. A low density, like that of Jupiter, implies a huge, low-density atmosphere, a gas giant. A higher density, like that of Earth, implies a rocky composition. Generally, the former has larger radii and the latter smaller.

According to Bai and his colleagues, this could be used to detect potential dark matter exoplanets. A dark matter exoplanet might have different properties than expected from ordinary exoplanets in ways that defy our current understanding of planet formation. You might get an exoplanet denser than iron, for instance, or one so low-density that its existence is impossible to explain.

Currently, no such outliers have been identified, but a scientist can dream.

In addition, astronomers have been able to probe the atmospheres of exoplanets based on transit data. They measure the spectrum of light from the star during transits and compare it to the light of the star normally, looking for dimmer and brighter wavelengths.

This signifies that some light has been absorbed and/or re-emitted by molecules in the exoplanet’s atmosphere; scientists can analyze this data to determine what those molecules are. If the transit spectrum reveals some serious anomalies, that could indicate the presence of a dark matter exoplanet.

If radial velocity suggests that an exoplanet should transit, and then no transit is observed, that could be a clue pointing to dark matter exoplanets. And if a transit dip, known as a light curve, displays an unexpected shape, that, too, could be a hint.

“Due to its tiny but non-vanishing interaction strength with the Standard Model particles, the dark matter exoplanet may not be completely opaque, rendering a light curve shape distinguishable from that of an ordinary exoplanet,” the researchers write.

Bai and his colleagues calculated what this light curve could look like, laying down the simple groundwork for a more complex theoretical analysis.

There are several ways the work could be improved, the team notes. They’ve only considered circular orbits, for example; many exoplanets, however, have elliptical orbits, especially those that may have been captured in a star’s gravity, as one might expect dark matter exoplanets to be. Also, planet properties have been kept relatively simple.

“Further study on early dark matter exoplanet–stellar-system formation and dark matter exoplanet capture would help in elucidating the possibility of detecting dark matter exoplanets and would be necessary for bounds to be set on dark matter exoplanet abundance if they are not detected,” the researchers conclude.
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Dark Matter Background
Fritz Zwicky discovered Dark Matter in the 1930s when observing the movement of the Coma Cluster., and Vera Rubin a Woman in STEM, denied the Nobel, some 30 years later, did most of the work on Dark Matter.

Fritz Zwicky.

Coma cluster via NASA/ESA Hubble, the original example of Dark Matter discovered during observations by Fritz Zwicky and confirmed 30 years later by Vera Rubin.

In modern times, it was astronomer Fritz Zwicky, in the 1930s, who made the first observations of what we now call dark matter. His 1933 observations of the Coma Cluster of galaxies seemed to indicated it has a mass 500 times more than that previously calculated by Edwin Hubble. Furthermore, this extra mass seemed to be completely invisible. Although Zwicky’s observations were initially met with much skepticism, they were later confirmed by other groups of astronomers.

Thirty years later, astronomer Vera Rubin provided a huge piece of evidence for the existence of dark matter. She discovered that the centers of galaxies rotate at the same speed as their extremities, whereas, of course, they should rotate faster. Think of a vinyl LP on a record deck: its center rotates faster than its edge. That’s what logic dictates we should see in galaxies too. But we do not. The only way to explain this is if the whole galaxy is only the center of some much larger structure, as if it is only the label on the LP so to speak, causing the galaxy to have a consistent rotation speed from center to edge.

Vera Rubin, following Zwicky, postulated that the missing structure in galaxies is dark matter. Her ideas were met with much resistance from the astronomical community, but her observations have been confirmed and are seen today as pivotal proof of the existence of dark matter.

Astronomer Vera Rubin at the Lowell Observatory in 1965, worked on Dark Matter (The Carnegie Institution for Science).

Vera Rubin, with Department of Terrestrial Magnetism (DTM) image tube spectrograph attached to the Kitt Peak 84-inch telescope, 1970.

Vera Rubin measuring spectra, worked on Dark Matter(Emilio Segre Visual Archives AIP SPL).

Dark Matter Research

Super Cryogenic Dark Matter Search from DOE’s SLAC National Accelerator Laboratory at Stanford University at SNOLAB (Vale Inco Mine, Sudbury, Canada).

LBNL LZ Dark Matter Experiment xenon detector at Sanford Underground Research Facility Credit: Matt Kapust.

Lambda Cold Dark Matter Expansion ΛCDM of the Universe. Credit Alex Mittelmann Coldcreation.

DAMA at Gran Sasso uses sodium iodide housed in copper to hunt for dark matter LNGS-INFN.

Yale HAYSTAC axion dark matter experiment at Yale’s Wright Lab.

DEAP Dark Matter detector, The DEAP-3600, suspended in the SNOLAB (CA) deep in Sudbury’s Creighton Mine.

The LBNL LZ Dark Matter Experiment Dark Matter project at SURF, Lead, SD.

DAMA-LIBRA Dark Matter experiment at the Italian National Institute for Nuclear Physics’ (INFN’s) Gran Sasso National Laboratories (LNGS) located in the Abruzzo region of central Italy.

DARWIN Dark Matter experiment. A design study for a next-generation, multi-ton dark matter detector in Europe at The University of Zurich [Universität Zürich](CH).

PandaX II Dark Matter experiment at Jin-ping Underground Laboratory (CJPL) in Sichuan, China.

Inside the Axion Dark Matter eXperiment U Washington. Credit: Mark Stone U. of Washington. Axion Dark Matter Experiment.

XENONnT experiment at the Laboratori Nazionali del Gran Sasso (LNGS) underground laboratory in Italy.

The University of Western Australia ORGAN Experiment’s main detector. A small copper cylinder called a “resonant cavity” traps photons generated during dark matter conversion. The cylinder is bolted to a “dilution refrigerator” which cools the experiment to very low temperatures.
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See the full article here .

Comments are invited and will be appreciated, especially if the reader finds any errors which I can correct. Use “Reply”.

five-ways-keep-your-child-safe-school-shootings

Please help promote STEM in your local schools.

Stem Education Coalition

The University of Wisconsin–Madison is a public land-grant research university in Madison, Wisconsin. Founded when Wisconsin achieved statehood in 1848, The University of Wisconsin-Madison is the official state university of Wisconsin and the flagship campus of the University of Wisconsin System. It was the first public university established in Wisconsin and remains the oldest and largest public university in the state. It became a land-grant institution in 1866. The 933-acre (378 ha) main campus, located on the shores of Lake Mendota, includes four National Historic Landmarks. The university also owns and operates a National Historic Landmark 1,200-acre (486 ha) arboretum established in 1932, located 4 miles (6.4 km) south of the main campus.

The University of Wisconsin-Madison is organized into 20 schools and colleges, which enrolled 30,361 undergraduate and 14,052 graduate students in 2018. Its academic programs include 136 undergraduate majors, 148 master’s degree programs, and 120 doctoral programs. A major contributor to Wisconsin’s economy, the university is the largest employer in the state, with over 21,600 faculty and staff.

The University of Wisconsin is one of the twelve founding members of The Association of American Universities, a selective group of major research universities in North America. It is considered a Public Ivy, and is classified as an R1 University, meaning that it engages in a very high level of research activity. In 2018, it had research and development expenditures of $1.2 billion, the eighth-highest among universities in the U.S. As of March 2020, 26 Nobel laureates, 2 Fields medalists and 1 Turing award winner have been associated with The University of Wisconsin-Madison as alumni, faculty, or researchers. Additionally, as of November 2018, the current CEOs of 14 Fortune 500 companies have attended The University of Wisconsin-Madison, the most of any university in the United States.

Among the scientific advances made at The University of Wisconsin-Madison are the single-grain experiment, the discovery of vitamins A and B by Elmer McCollum and Marguerite Davis, the development of the anticoagulant medication warfarin by Karl Paul Link, the first chemical synthesis of a gene by Har Gobind Khorana, the discovery of the retroviral enzyme reverse transcriptase by Howard Temin, and the first synthesis of human embryonic stem cells by James Thomson The University of Wisconsin-Madison was also the home of both the prominent “Wisconsin School” of economics and of diplomatic history, while UW–Madison professor Aldo Leopold played an important role in the development of modern environmental science and conservationism.

The University of Wisconsin-Madison Badgers compete in 25 intercollegiate sports in the NCAA Division I Big Ten Conference and have won 30 national championships. Wisconsin students and alumni have won 50 Olympic medals (including 13 gold medals).

Research

The University of Wisconsin-Madison was a founding member of The Association of American Universities. In fiscal year 2018 the school received $1.206 billion in research and development (R&D) funding, placing it eighth in the U.S. among institutions of higher education. Its research programs were fourth in the number of patents issued in 2010.

The University of Wisconsin–Madison is one of 33 sea grant colleges in the United States. These colleges are involved in scientific research, education, training, and extension projects geared toward the conservation and practical use of U.S. coasts, the Great Lakes and other marine areas.

The University of Wisconsin-Madison maintains almost 100 research centers and programs, ranging from agriculture to arts, from education to engineering. It has been considered a major academic center for embryonic stem cell research ever since The University of Wisconsin-Madison professor James Thomson became the first scientist to isolate human embryonic stem cells. This has brought significant attention and respect for The University of Wisconsin-Madison research programs from around the world. The University of Wisconsin-Madison continues to be a leader in stem cell research, helped in part by the funding of The University of Wisconsin-Madison Alumni Research Foundation and promotion of WiCell.

Its center for research on internal combustion engines, called the Engine Research Center, has a five-year collaboration agreement with General Motors. It has also been the recipient of multimillion-dollar funding from the federal government.

In June 2013, it is reported that The National Institutes of Health would fund an $18.13 million study at the University of Wisconsin. The study will research lethal qualities of viruses such as Ebola, West Nile and influenza. The goal of the study is to help find new drugs to fight off the most lethal pathogens.

In 2012, The University of Wisconsin-Madison experiments on cats came under fire from People for the Ethical Treatment of Animals who claimed the animals were abused. In 2013, the NIH briefly suspended the research’s funding pending an agency investigation. The following year the university was fined more than $35,000 for several violations of the Animal Welfare Act. Bill Maher, James Cromwell and others spoke out against the experiments that ended in 2014. The university defended the research and the care the animals received claiming that PETA’s objections were merely a “stunt” by the organization.

As of October 2018, 26 Nobel laureates and 2 Fields medalists have been associated with The University of Wisconsin-Madison as alumni, faculty, or researchers. Additionally, as of November 2018, the current CEOs of 14 Fortune 500 companies have attended The University of Wisconsin-Madison, the most of any university in the United States. Notable CEOs who have attended UW-Madison include Thomas J. Falk (Kimberly-Clark), Carol Bartz (Yahoo!), David J. Lesar (Halliburton), Keith Nosbusch (Rockwell Automation), Lee Raymond (Exxon Mobil), Tom Kingsbury (Burlington Stores), and Judith Faulkner (Epic Systems).

As of 2017, The University of Wisconsin-Madison had more than 427,000 living alumni. Although a large number of alumni live in Wisconsin, a significant number live in Illinois, Minnesota, New York, California, and Washington, D.C.

UW–Madison alumni, faculty, or former faculty have been awarded 26 Nobel Prizes and 38 Pulitzer Prizes.

From “Discover Magazine” : “Cosmologists say black holes are accelerating the expansion of the universe”

From “Discover Magazine”

2.21.23

Universe map Sloan Digital Sky Survey (SDSS) 2dF Galaxy Redshift Survey.

Our universe began with a puzzle. For 100 million years after the Big Bang, it expanded. Then something strange happened — this expansion suddenly accelerated and has continued to accelerate ever since.
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Inflation

In physical cosmology, cosmic inflation, cosmological inflation is a theory of exponential expansion of space in the early universe. The inflationary epoch lasted from 10^−36 seconds after the conjectured Big Bang singularity to some time between 10^−33 and 10^−32 seconds after the singularity. Following the inflationary period, the universe continued to expand, but at a slower rate. The acceleration of this expansion due to dark energy began after the universe was already over 7.7 billion years old (5.4 billion years ago).

Inflation theory was developed in the late 1970s and early 80s, with notable contributions by several theoretical physicists, including Alexei Starobinsky at Landau Institute for Theoretical Physics, Alan Guth at Cornell University, and Andrei Linde at Lebedev Physical Institute. Alexei Starobinsky, Alan Guth, and Andrei Linde won the 2014 Kavli Prize “for pioneering the theory of cosmic inflation.” It was developed further in the early 1980s. It explains the origin of the large-scale structure of the cosmos. Quantum fluctuations in the microscopic inflationary region, magnified to cosmic size, become the seeds for the growth of structure in the Universe. Many physicists also believe that inflation explains why the universe appears to be the same in all directions (isotropic), why the cosmic microwave background radiation is distributed evenly, why the universe is flat, and why no magnetic monopoles have been observed.

The detailed particle physics mechanism responsible for inflation is unknown. The basic inflationary paradigm is accepted by most physicists, as a number of inflation model predictions have been confirmed by observation; however, a substantial minority of scientists dissent from this position. The hypothetical field thought to be responsible for inflation is called the inflaton.

In 2002 three of the original architects of the theory were recognized for their major contributions; physicists Alan Guth of M.I.T., Andrei Linde of Stanford, and Paul Steinhardt of Princeton shared the prestigious Dirac Prize “for development of the concept of inflation in cosmology”. In 2012 Guth and Linde were awarded the Breakthrough Prize in Fundamental Physics for their invention and development of inflationary cosmology.

Alan Guth, from M.I.T., who first proposed Cosmic Inflation.

Lambda Cold Dark Matter Expansion ΛCDM of the Universe. Credit Alex Mittelmann Coldcreation.

Alan Guth’s notes:
Alan Guth’s original notes on inflation.
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Today cosmologists think some kind of pressure must have forced this acceleration, all powered by huge amounts of energy from an unknown source. Cosmologists call it dark energy.
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The Dark Energy Survey

Dark Energy Camera [DECam] built at The DOE’s Fermi National Accelerator Laboratory.

NOIRLab National Optical Astronomy Observatory Cerro Tololo Inter-American Observatory (CL) Victor M Blanco 4m Telescope which houses the Dark-Energy-Camera – DECam at Cerro Tololo, Chile at an altitude of 7200 feet.

NOIRLabNSF NOIRLab NOAO Cerro Tololo Inter-American Observatory(CL) approximately 80 km to the East of La Serena, Chile, at an altitude of 2200 meters.

Timeline of the Inflationary Universe NASA WMAP LAMBDA – ΛCDM Model of Cosmology

The Dark Energy Survey is an international, collaborative effort to map hundreds of millions of galaxies, detect thousands of supernovae, and find patterns of cosmic structure that will reveal the nature of the mysterious dark energy that is accelerating the expansion of our Universe. The Dark Energy Survey began searching the Southern skies on August 31, 2013.

According to Albert Einstein’s Theory of General Relativity, gravity should lead to a slowing of the cosmic expansion. Yet, in 1998, two teams of astronomers studying distant supernovae made the remarkable discovery that the expansion of the universe is speeding up.

Nobel Prize in Physics for 2011 Expansion of the Universe

Saul Perlmutter (center) [The Supernova Cosmology Project] shared the 2006 Shaw Prize in Astronomy, the 2011 Nobel Prize in Physics, and the 2015 Breakthrough Prize in Fundamental Physics with Brian P. Schmidt (right) and Adam Riess (left) [The High-z Supernova Search Team] for providing evidence that the expansion of the universe is accelerating.

4 October 2011

The Royal Swedish Academy of Sciences has decided to award the Nobel Prize in Physics for 2011

with one half to

Saul Perlmutter
The Supernova Cosmology Project
The DOE’s Lawrence Berkeley National Laboratory and The University of California-Berkeley,

and the other half jointly to

Brian P. Schmidt
The High-z Supernova Search Team, The Australian National University, Weston Creek, Australia.

and

Adam G. Riess
The High-z Supernova Search Team,The Johns Hopkins University and The Space Telescope Science Institute, Baltimore, MD.
Written in the stars

“Some say the world will end in fire, some say in ice…” *

What will be the final destiny of the Universe? Probably it will end in ice, if we are to believe this year’s Nobel Laureates in Physics. They have studied several dozen exploding stars, called supernovae, and discovered that the Universe is expanding at an ever-accelerating rate. The discovery came as a complete surprise even to the Laureates themselves.

In 1998, cosmology was shaken at its foundations as two research teams presented their findings. Headed by Saul Perlmutter, one of the teams had set to work in 1988. Brian Schmidt headed another team, launched at the end of 1994, where Adam Riess was to play a crucial role.

The research teams raced to map the Universe by locating the most distant supernovae. More sophisticated telescopes on the ground and in space, as well as more powerful computers and new digital imaging sensors (CCD, Nobel Prize in Physics in 2009), opened the possibility in the 1990s to add more pieces to the cosmological puzzle.

The teams used a particular kind of supernova, called Type 1a supernova. It is an explosion of an old compact star that is as heavy as the Sun but as small as the Earth. A single such supernova can emit as much light as a whole galaxy. All in all, the two research teams found over 50 distant supernovae whose light was weaker than expected – this was a sign that the expansion of the Universe was accelerating. The potential pitfalls had been numerous, and the scientists found reassurance in the fact that both groups had reached the same astonishing conclusion.

For almost a century, the Universe has been known to be expanding as a consequence of the Big Bang about 14 billion years ago.

Edwin Hubble looking through the 100-inch Hooker telescope at Mount Wilson in Southern California, 1929 discovers the Universe is Expanding. Credit: Margaret Bourke-White/Time & Life Pictures/Getty Images.

Edwin Hubble Cepheid variable with Messier 31 at the 100 inch Hooker telescope on Mt Wilson, California.

However, the discovery that this expansion is accelerating is astounding. If the expansion will continue to speed up the Universe will end in ice.

The acceleration is thought to be driven by dark energy, but what that dark energy is remains an enigma – perhaps the greatest in physics today. What is known is that dark energy constitutes about three quarters of the Universe. Therefore the findings of the 2011 Nobel Laureates in Physics have helped to unveil a Universe that to a large extent is unknown to science. And everything is possible again.

*Robert Frost, Fire and Ice, 1920
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To explain cosmic acceleration, cosmologists are faced with two possibilities: either 70% of the universe exists in an exotic form, now called Dark Energy, that exhibits a gravitational force opposite to the attractive gravity of ordinary matter, or Albert Einstein’s Theory of General Relativity must be replaced by a new theory of gravity on cosmic scales.

The Dark Energy Survey is designed to probe the origin of the accelerating universe and help uncover the nature of Dark Energy by measuring the 14-billion-year history of cosmic expansion with high precision. More than 400 scientists from over 25 institutions in the United States, Spain, the United Kingdom, Brazil, Germany, Switzerland, and Australia are working on the project. The collaboration built and is using an extremely sensitive 570-Megapixel digital camera, DECam, mounted on the Blanco 4-meter telescope at Cerro Tololo Inter-American Observatory, high in the Chilean Andes, to carry out the project.

Over six years (2013-2019), the Dark Energy Survey collaboration used 758 nights of observation to carry out a deep, wide-area survey to record information from 300 million galaxies that are billions of light-years from Earth. The survey imaged 5000 square degrees of the southern sky in five optical filters to obtain detailed information about each galaxy. A fraction of the survey time is used to observe smaller patches of sky roughly once a week to discover and study thousands of supernovae and other astrophysical transients.
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But why this accelerating expansion occurred, and why it happened at that time, is one of the great unsolved mysteries in science.

Now Duncan Farrah and the University of Hawaii in Honolulu and colleagues think they know the answer. They say the acceleration is the result of a previously unknown interaction between black holes and spacetime. When spacetime expands, they say, this interaction makes black holes more massive and this extra mass accelerates the expansion of the universe, creating the accelerated expansion we see today.

Spacetime Theories

First some background. The new idea has its origins in the work of theoretical physicists who have recently shown that black holes cannot be independent of the spacetime in which they sit. Instead, spacetime and black holes must be coupled in such a way that a change in the properties of one immediately influences the properties of the other.

So how might this manifest itself? One possibility is that any stretching of spacetime as it expands makes black holes more massive. An analogous effect is the way the same stretching causes light from the early universe to become red-shifted as it travels through space and time to be observed today.

Farrah and Co reasoned that if this coupling does occur, then black holes in the early universe would be less massive than those in the more recent past. So they looked for evidence by studying supermassive black holes at the center of galaxies.

It turns out that supermassive black holes in the closer, more recent universe are up to 20 times more massive than those in the more distant, early universe (relative to the mass of the stars around them). “We find evidence for cosmologically coupled mass growth among these black holes,” they say.

This growth cannot be explained by the black holes swallowing nearby stars — there aren’t enough of them. Nor cannot it be explained by the merger of supermassive black holes as galaxies collide, since this would not change the mass ratio of nearby stars.

Instead, Farrah and Co say this is evidence that black hole mass must be coupled to spacetime and must increase as the universe expands. Indeed, the change in mass over time is consistent with this explanation.

But this increase in mass itself exerts a pressure on spacetime. Farrah and Co say this the pressure, or dark energy, causes the expansion of the universe to accelerate. Indeed, their calculations suggest this pressure is the order of magnitude necessary to explain the observed expansion rate.

It also explains why the accelerated expansion began only after the universe was 100 million years old, a time that cosmologists refer to by its redshift, denoted z. In this case z ∼ 0.7.

The answer is because black holes form when stars die and so can only have begun to influence the expansion after the first stars had formed. That was 100 million years after the big bang.

“We thus propose that stellar remnant black holes are the astrophysical origin of dark energy, explaining the onset of accelerating expansion at z ∼ 0.7” say the team.

Dark Origins

The same idea could explain another of cosmology’s great mysteries— why the structure of the universe that we can see seems to be influenced by the gravitational pull of stuff we cannot see, so-called dark matter.

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Dark Matter Background
Fritz Zwicky discovered Dark Matter in the 1930s when observing the movement of the Coma Cluster., and Vera Rubin a Woman in STEM, denied the Nobel, some 30 years later, did most of the work on Dark Matter.

Fritz Zwicky.

Coma cluster via NASA/ESA Hubble, the original example of Dark Matter discovered during observations by Fritz Zwicky and confirmed 30 years later by Vera Rubin.

In modern times, it was astronomer Fritz Zwicky, in the 1930s, who made the first observations of what we now call dark matter. His 1933 observations of the Coma Cluster of galaxies seemed to indicated it has a mass 500 times more than that previously calculated by Edwin Hubble. Furthermore, this extra mass seemed to be completely invisible. Although Zwicky’s observations were initially met with much skepticism, they were later confirmed by other groups of astronomers.

Thirty years later, astronomer Vera Rubin provided a huge piece of evidence for the existence of dark matter. She discovered that the centers of galaxies rotate at the same speed as their extremities, whereas, of course, they should rotate faster. Think of a vinyl LP on a record deck: its center rotates faster than its edge. That’s what logic dictates we should see in galaxies too. But we do not. The only way to explain this is if the whole galaxy is only the center of some much larger structure, as if it is only the label on the LP so to speak, causing the galaxy to have a consistent rotation speed from center to edge.

Vera Rubin, following Zwicky, postulated that the missing structure in galaxies is dark matter. Her ideas were met with much resistance from the astronomical community, but her observations have been confirmed and are seen today as pivotal proof of the existence of dark matter.

Astronomer Vera Rubin at the Lowell Observatory in 1965, worked on Dark Matter (The Carnegie Institution for Science).

Vera Rubin, with Department of Terrestrial Magnetism (DTM) image tube spectrograph attached to the Kitt Peak 84-inch telescope, 1970.

Vera Rubin measuring spectra, worked on Dark Matter(Emilio Segre Visual Archives AIP SPL).

Dark Matter Research

Super Cryogenic Dark Matter Search from DOE’s SLAC National Accelerator Laboratory at Stanford University at SNOLAB (Vale Inco Mine, Sudbury, Canada).

LBNL LZ Dark Matter Experiment xenon detector at Sanford Underground Research Facility Credit: Matt Kapust.

Lambda Cold Dark Matter Expansion ΛCDM of the Universe. Credit Alex Mittelmann Coldcreation.

DAMA at Gran Sasso uses sodium iodide housed in copper to hunt for dark matter LNGS-INFN.

Yale HAYSTAC axion dark matter experiment at Yale’s Wright Lab.

DEAP Dark Matter detector, The DEAP-3600, suspended in the SNOLAB (CA) deep in Sudbury’s Creighton Mine.

The LBNL LZ Dark Matter Experiment Dark Matter project at SURF, Lead, SD.

DAMA-LIBRA Dark Matter experiment at the Italian National Institute for Nuclear Physics’ (INFN’s) Gran Sasso National Laboratories (LNGS) located in the Abruzzo region of central Italy.

DARWIN Dark Matter experiment. A design study for a next-generation, multi-ton dark matter detector in Europe at The University of Zurich [Universität Zürich](CH).

PandaX II Dark Matter experiment at Jin-ping Underground Laboratory (CJPL) in Sichuan, China.

Inside the Axion Dark Matter eXperiment U Washington. Credit: Mark Stone U. of Washington. Axion Dark Matter Experiment.

XENONnT experiment at the Laboratori Nazionali del Gran Sasso (LNGS) underground laboratory in Italy.

The University of Western Australia ORGAN Experiment’s main detector. A small copper cylinder called a “resonant cavity” traps photons generated during dark matter conversion. The cylinder is bolted to a “dilution refrigerator” which cools the experiment to very low temperatures.
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One hypothesized explanation for this is that dark matter takes the form of massive compact halo objects, or MACHOs, that float through interstellar space but do not emit much radiation and so are hard to observe.

Farrah and Co’s theory applies to black holes at every scale, from a those few times the mass of our sun to those that are many millions of times bigger. They point out that the smallest black holes form a population that is consistent with properties MACHOs.

“If these BHs are distributed in galactic halos, they will form a population of Massive Compact Halo Objects,” say Farrah and co. In other words, their theory also explains the origin of dark matter.

The team go on to make several predictions that could make or break their theory. For example, they say the effect of this black hole-spacetime coupling should have an observable influence on the cosmic microwave background [CMB], the echo of the big bang that astronomers have been observing with increasing precision for decades.

Arno Penzias and Robert Wilson, AT&T, Holmdel, NJ USA, with the Holmdel horn antenna, first caught the faint echo of the Big Bang.

CMB per European Space Agency(EU) Planck.

The European Space Agency [La Agencia Espacial Europea] [Agence spatiale européenne][Europäische Weltraumorganization](EU) Planck microwave telescope 2009 to 2013.

Farrah and co also predict how the coupling effect should influence the properties of the mysterious gamma ray bursts that astronomers observe from various parts of the universe.

Gamma-ray burst. Credit: Cruz Dewilde/ NASA SWIFT.

And they say that the coupling between black holes and spacetime should influence the rate at which small black holes merge. “This can lead to significant increases in merger rate,” they say. The mergers of small black holes have recently become observable thanks to the detection of gravitational waves.

These predictions should be readily testable in the near future. If Farrah and co are correct, then observational conformation of their idea should begin trickling in over the next few months and years.

There will also be inevitable disputes. But make no mistake—an explanation for the origin of dark energy and dark matter will be a major breakthrough in astronomy and one that solves one of the outstanding mysteries of our time.

The Astrophysical Journal Letters

Figure 1.

(Top) Posterior distributions of cosmological coupling strength k, inferred by comparing SMBHs in local elliptical
galaxies to those in five samples of elliptical galaxies at z > 0.7. (Bottom) Combining these posterior samples with equal weighting gives a distribution with k = 3.11+1.19−1.33 at 90% confidence. If fit to a Gaussian, the fit has a mean of k = 3.09 with a standard deviation of 0.76 (shading). Vertical lines indicate: k = 0 coupling, as expected for traditional BHs like Kerr and the decoupled solution by Nolan (1993); and k = 3 coupling, as predicted for vacuum energy interior BHs. The measurement disfavors zero coupling at 99.98% confidence and is consistent with BHs possessing vacuum energy interiors, as first suggested by Gliner (1966).

Figure 2.

Cosmic star formation rate densities (SFRDs) capable of producing the necessary k = 3 BH density to give
ΩΛ = 0.68 (green, solid). The details of the model are given in Appendix A. The upper bound of the viable region adopts
a Kroupa (2002) IMF at all redshifts with the least amount of remnant accretion required to produce ΩΛ with a decreasing
power-law SFRD model (red, solid). The lower bound adopts the top-heavy IMF of Harikane et al. (2022a) at z > 7 (blue,
solid). Two middle lines show the impact of a top-heavy IMF at z > 7, but no remnant accretion (green, solid); and higher
accretion, but with a Kroupa IMF (orange, solid). Existing measurements of the SFRD via IR (Rowan-Robinson et al. 2018,
red, squares), γ-ray bursts (Kistler et al. 2009, orange, stars), FIR (Algera et al. 2023, brown, xs), and rest-frame UV via JWST (Donnan et al. 2022; Harikane et al. 2022a, purple, dots), (Bouwens et al. 2022, blue, dots) are over-plotted. The UV points can vary ∼ −1 dex depending upon IMF assumptions and UV luminosity integration bounds. Consistency occurs with consumption of < 3% of the baryon fraction Ωb after cosmic dawn. The results assume stellar first light at z? = 25 (Harikane et al. 2022b, Fig 25) but are typical of the scenario for 15 < z? < 35. Also indicated are the redshifts probed by 21cm experiments.

Fig 3.

(Vertical bars) Fraction of z = 0 halo density contributed by k = 3 BHs, as produced by the indicated SFRDs in
Figure 2. Models are ordered by increasing SFRD power-law slope, with colors set to agree with the model lines in Figure 2. Also displayed (grey, shaded) are current constraints on MACHOs from microlensing (Blaineau et al. 2022), wide halo binary disruption (Tyler et al. 2022; Monroy-Rodr ́ıguez & Allen 2014), and ultra-faint dwarf (UFD) galaxy disruption (Brandt 2016). Noting the broken vertical axis, the microlensing and halo binary constraints are easily satisfied. Dwarf galaxy constraints may discriminate candidate SFRD and IMF combinations. As shown, UFD constraints are overlyconservative because they do not account for the decrease in comoving BH mass density at earlier times, as will be present in the k > 0 coupled scenario. The effects of accretion at z > 7, as well as adopting a top-heavy IMF (Appendix A), are visible as decreased fraction in the IMBH range. (Horizontal bars) Fraction of present-day ΩΛ contributed by each mass bin. Mass bins that contribute < 5% of ΩΛ are unlabeled for clarity. Color gradients indicate mass binning and are common to both vertical and horizontal bars. Contributionsless than 1%, including negligible contributions omitted in the vertical bars, are also shown in log scaling. Here, contributions are ordered by density fraction.

See the full article here .

Comments are invited and will be appreciated, especially if the reader finds any errors which I can correct. Use “Reply”.

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From The University of Michigan And The Johannes Gutenberg University Mainz [Johannes Gutenberg-Universität Mainz] (DE): “A new model for dark matter”

From The University of Michigan

And

The Johannes Gutenberg University Mainz [Johannes Gutenberg-Universität Mainz] (DE)

1.23.23
Bernie DeGroat
734-647-1847
bernied@umich.edu

Phase transition in early universe changes strength of interaction between dark and normal matter.

This NASA Hubble Space Telescope image shows the distribution of dark matter in the center of the giant galaxy cluster Abell 1689, containing about 1,000 galaxies and trillions of stars. Dark matter is an invisible form of matter that accounts for most of the universe’s mass. Hubble cannot see the dark matter directly. Astronomers inferred its location by analyzing the effect of gravitational lensing, where light from galaxies behind Abell 1689 is distorted by intervening matter within the cluster.

Gravitational Lensing National Aeronautics Space Agency and European Space Agency [La Agencia Espacial Europea][Agence spatiale européenne][Europäische Weltraumorganization](EU).

Researchers used the observed positions of 135 lensed images of 42 background galaxies to calculate the location and amount of dark matter in the cluster. They superimposed a map of these inferred dark matter concentrations, tinted blue, on an image of the cluster taken by Hubble’s Advanced Camera for Surveys.

National Aeronautics Space Agency/European Space Agency [La Agencia Espacial Europea][Agence spatiale européenne][Europäische Weltraumorganization](EU) Advanced Camera for Surveys (ACS) on the NASA/ESA Hubble Space Telescope.

If the cluster’s gravity came only from the visible galaxies, the lensing distortions would be much weaker. The map reveals that the densest concentration of dark matter is in the cluster’s core. Abell 1689 resides 2.2 billion light-years from Earth. The image was taken in June 2002. Image credit: D. Coe (NASA Jet Propulsion Laboratory/California Institute of Technology, and Space Telescope Science Institute) NASA/ESA; , N. Benitez (Institute of Astrophysics of Andalusia, Spain), T. Broadhurst (University of the Basque Country, Spain), and H. Ford (Johns Hopkins University).

Dark matter remains one of the greatest mysteries of modern physics. It is clear that it must exist, because without dark matter, for example, the motion of galaxies cannot be explained. But it has never been possible to detect dark matter in an experiment.

Currently, there are many proposals for new experiments: They aim to detect dark matter directly via its scattering from the constituents of the atomic nuclei of a detection medium, i.e., protons and neutrons.

A team of researchers—Robert McGehee and Aaron Pierce of the University of Michigan and Gilly Elor of Johannes Gutenberg University of Mainz in Germany—has now proposed a new candidate for dark matter-“HYPER”: “HighlY Interactive ParticlE Relics.”

In the HYPER model some time after the formation of dark matter in the early universe the strength of its interaction with normal matter increases abruptly—which on the one hand makes it potentially detectable today and at the same time can explain the abundance of dark matter.

The new diversity in the dark matter sector

Since the search for heavy dark matter particles, or so-called WIMPS, has not yet led to success, the research community is looking for alternative dark matter particles, especially lighter ones. At the same time, one generically expects phase transitions in the dark sector—after all, there are several in the visible sector, the researchers say. But previous studies have tended to neglect them.

“There has not been a consistent dark matter model for the mass range that some planned experiments hope to access. “However, our HYPER model illustrates that a phase transition can actually help make the dark matter more easily detectable,” said Elor, a postdoctoral researcher in theoretical physics at JGU.

The challenge for a suitable model: If dark matter interacts too strongly with normal matter, its (precisely known) amount formed in the early universe would be too small, contradicting astrophysical observations. However, if it is produced in just the right amount, the interaction would conversely be too weak to detect dark matter in present-day experiments.

“Our central idea, which underlies the HYPER model, is that the interaction changes abruptly once—so we can have the best of both worlds: the right amount of dark matter and a large interaction so we might detect it,” McGehee said.

Constraints in the mediator mass-nucleon coupling plane from cooling of HB stars [25] and SN 1987A [12], as well as rare kaon decays [26] (gray shading). Credit: Physical Review Letters (2023).

And this is how the researchers envision it: In particle physics an interaction is usually mediated by a specific particle, a so-called mediator—and so is the interaction of dark matter with normal matter. Both the formation of dark matter and its detection function via this mediator, with the strength of the interaction depending on its mass: The larger the mass, the weaker the interaction.

The mediator must first be heavy enough so that the correct amount of dark matter is formed and later light enough so that dark matter is detectable at all. The solution: There was a phase transition after the formation of dark matter, during which the mass of the mediator suddenly decreased.

“Thus, on the one hand, the amount of dark matter is kept constant, and on the other hand, the interaction is boosted or strengthened in such a way that dark matter should be directly detectable,” Pierce said.

New model covers almost the full parameter range of planned experiments

“The HYPER model of dark matter is able to cover almost the entire range that the new experiments make accessible,” Elor said.

Specifically, the research team first considered the maximum cross section of the mediator-mediated interaction with the protons and neutrons of an atomic nucleus to be consistent with astrological observations and certain particle-physics decays. The next step was to consider whether there was a model for dark matter that exhibited this interaction.

“And here we came up with the idea of the phase transition,” McGehee said. “We then calculated the amount of dark matter that exists in the universe and then simulated the phase transition using our calculations.”

There are a great many constraints to consider, such as a constant amount of dark matter.

“Here, we have to systematically consider and include very many scenarios, for example, asking the question whether it is really certain that our mediator does not suddenly lead to the formation of new dark matter, which of course must not be,” Elor said. “But in the end, we were convinced that our HYPER model works.”

The research is published in the journal Physical Review Letters.
__________________________________
Dark Matter Background
Fritz Zwicky discovered Dark Matter in the 1930s when observing the movement of the Coma Cluster., and Vera Rubin a Woman in STEM, denied the Nobel, some 30 years later, did most of the work on Dark Matter.

Fritz Zwicky.

Coma cluster via NASA/ESA Hubble, the original example of Dark Matter discovered during observations by Fritz Zwicky and confirmed 30 years later by Vera Rubin.

In modern times, it was astronomer Fritz Zwicky, in the 1930s, who made the first observations of what we now call dark matter. His 1933 observations of the Coma Cluster of galaxies seemed to indicated it has a mass 500 times more than that previously calculated by Edwin Hubble. Furthermore, this extra mass seemed to be completely invisible. Although Zwicky’s observations were initially met with much skepticism, they were later confirmed by other groups of astronomers.

Thirty years later, astronomer Vera Rubin provided a huge piece of evidence for the existence of dark matter. She discovered that the centers of galaxies rotate at the same speed as their extremities, whereas, of course, they should rotate faster. Think of a vinyl LP on a record deck: its center rotates faster than its edge. That’s what logic dictates we should see in galaxies too. But we do not. The only way to explain this is if the whole galaxy is only the center of some much larger structure, as if it is only the label on the LP so to speak, causing the galaxy to have a consistent rotation speed from center to edge.

Vera Rubin, following Zwicky, postulated that the missing structure in galaxies is dark matter. Her ideas were met with much resistance from the astronomical community, but her observations have been confirmed and are seen today as pivotal proof of the existence of dark matter.

Astronomer Vera Rubin at the Lowell Observatory in 1965, worked on Dark Matter (The Carnegie Institution for Science).

Vera Rubin, with Department of Terrestrial Magnetism (DTM) image tube spectrograph attached to the Kitt Peak 84-inch telescope, 1970.

Vera Rubin measuring spectra, worked on Dark Matter(Emilio Segre Visual Archives AIP SPL).

Dark Matter Research

Super Cryogenic Dark Matter Search from DOE’s SLAC National Accelerator Laboratory at Stanford University at SNOLAB (Vale Inco Mine, Sudbury, Canada).

LBNL LZ Dark Matter Experiment xenon detector at Sanford Underground Research Facility Credit: Matt Kapust.

Lambda Cold Dark Matter Expansion ΛCDM of the Universe. Credit Alex Mittelmann Coldcreation.

DAMA at Gran Sasso uses sodium iodide housed in copper to hunt for dark matter LNGS-INFN.

Yale HAYSTAC axion dark matter experiment at Yale’s Wright Lab.

DEAP Dark Matter detector, The DEAP-3600, suspended in the SNOLAB (CA) deep in Sudbury’s Creighton Mine.

The LBNL LZ Dark Matter Experiment Dark Matter project at SURF, Lead, SD.

DAMA-LIBRA Dark Matter experiment at the Italian National Institute for Nuclear Physics’ (INFN’s) Gran Sasso National Laboratories (LNGS) located in the Abruzzo region of central Italy.

DARWIN Dark Matter experiment. A design study for a next-generation, multi-ton dark matter detector in Europe at The University of Zurich [Universität Zürich](CH).

PandaX II Dark Matter experiment at Jin-ping Underground Laboratory (CJPL) in Sichuan, China.

Inside the Axion Dark Matter eXperiment U Washington. Credit: Mark Stone U. of Washington. Axion Dark Matter Experiment.

XENONnT experiment at the Laboratori Nazionali del Gran Sasso (LNGS) underground laboratory in Italy.

The University of Western Australia ORGAN Experiment’s main detector. A small copper cylinder called a “resonant cavity” traps photons generated during dark matter conversion. The cylinder is bolted to a “dilution refrigerator” which cools the experiment to very low temperatures.
__________________________________

See the full article here .

Comments are invited and will be appreciated, especially if the reader finds any errors which I can correct. Use “Reply”.

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The The Johannes Gutenberg University Mainz [Johannes Gutenberg-Universität Mainz] (DE) is a public research university in Mainz, Rhineland Palatinate, Germany, named after the printer Johannes Gutenberg since 1946. With approximately 32,000 students (2018) in about 100 schools and clinics, it is among the largest universities in Germany. Starting on 1 January 2005 the university was reorganized into 11 faculties of study.

The university is a member of the German U15, a coalition of fifteen major research-intensive and leading medical universities in Germany. The Johannes Gutenberg University is considered one of the most prestigious universities in Germany.

The university is part of the IT-Cluster Rhine-Main-Neckar. The Johannes Gutenberg University Mainz, The Goethe University Frankfurt(DE) and The Technische Universität Darmstadt(DE) together form the Rhine-Main-Universities [Rhein-Main Universitäten](DE)(RMU).

The first University of Mainz goes back to the Archbishop of Mainz, Prince-elector and Reichserzkanzler Adolf II von Nassau. At the time, establishing a university required papal approval and Adolf II initiated the approval process during his time in office. The university, however, was first opened in 1477 by Adolf’s successor to the bishopric, Diether von Isenburg. In 1784 the University was opened up for Protestants and Jews (curator Anselm Franz von Betzel). It fastly became one of the largest Catholic universities in Europe with ten chairs in theology alone. In the confusion after the establishment of the Mainz Republic of 1792 and its subsequent recapture by the Prussians, academic activity came to a gradual standstill. In 1798 the university became active again under French governance, and lectures in the department of medicine took place until 1823. Only the faculty of theology continued teaching during the 19th century, albeit as a theological Seminary (since 1877 “College of Philosophy and Theology”).

The current Johannes Gutenberg University Mainz was founded in 1946 by the French occupying power. In a decree on 1 March the French military government implied that the University of Mainz would continue to exist: the University shall be “enabled to resume its function”. The remains of anti-aircraft warfare barracks erected in 1938 after the remilitarization of the Rhineland during the Third Reich served as the university’s first buildings and are still in use today.

The continuation of academic activity between the old university and Johannes Gutenberg University Mainz, in spite of an interruption spanning over 100 years, is contested. During the time up to its reopening only a seminary and midwifery college survived.

In 1972, the effect of the 1968 student protests began to take a toll on the University’s structure. The departments (Fakultäten) were dismantled and the University was organized into broad fields of study (Fachbereiche). Finally in 1974 Peter Schneider was elected as the first president of what was now a “constituted group-university” institute of higher education. In 1990 Jürgen Zöllner became University President yet spent only a year in the position after he was appointed Minister for “Science and Advanced Education” for the State of Rhineland-Palatinate. As the coordinator for the SPD’s higher education policy, this furloughed professor from the Institute for Physiological Chemistry played a decisive role in the SPD’s higher education policy and in the development of Study Accounts.

The University of Michigan is a public research university located in Ann Arbor, Michigan, United States. Originally, founded in 1817 in Detroit as the Catholepistemiad, or University of Michigania, 20 years before the Michigan Territory officially became a state, the University of Michigan is the state’s oldest university. The university moved to Ann Arbor in 1837 onto 40 acres (16 ha) of what is now known as Central Campus. Since its establishment in Ann Arbor, the university campus has expanded to include more than 584 major buildings with a combined area of more than 34 million gross square feet (781 acres or 3.16 km²), and has two satellite campuses located in Flint and Dearborn. The University was one of the founding members of the Association of American Universities.

Considered one of the foremost research universities in the United States, the university has very high research activity and its comprehensive graduate program offers doctoral degrees in the humanities, social sciences, and STEM fields (Science, Technology, Engineering and Mathematics) as well as professional degrees in business, medicine, law, pharmacy, nursing, social work and dentistry. Michigan’s body of living alumni (as of 2012) comprises more than 500,000. Besides academic life, Michigan’s athletic teams compete in Division I of the NCAA and are collectively known as the Wolverines. They are members of the Big Ten Conference.

At over $12.4 billion in 2019, Michigan’s endowment is among the largest of any university. As of October 2019, 53 MacArthur “genius award” winners (29 alumni winners and 24 faculty winners), 26 Nobel Prize winners, six Turing Award winners, one Fields Medalist and one Mitchell Scholar have been affiliated with the university. Its alumni include eight heads of state or government, including President of the United States Gerald Ford; 38 cabinet-level officials; and 26 living billionaires. It also has many alumni who are Fulbright Scholars and MacArthur Fellows.

Research

Michigan is one of the founding members (in the year 1900) of the Association of American Universities. With over 6,200 faculty members, 73 of whom are members of the National Academy and 471 of whom hold an endowed chair in their discipline, the university manages one of the largest annual collegiate research budgets of any university in the United States. According to the National Science Foundation, Michigan spent $1.6 billion on research and development in 2018, ranking it 2nd in the nation. This figure totaled over $1 billion in 2009. The Medical School spent the most at over $445 million, while the College of Engineering was second at more than $160 million. U-M also has a technology transfer office, which is the university conduit between laboratory research and corporate commercialization interests.

In 2009, the university signed an agreement to purchase a facility formerly owned by Pfizer. The acquisition includes over 170 acres (0.69 km^2) of property, and 30 major buildings comprising roughly 1,600,000 square feet (150,000 m^2) of wet laboratory space, and 400,000 square feet (37,000 m^2) of administrative space. At the time of the agreement, the university’s intentions for the space were not set, but the expectation was that the new space would allow the university to ramp up its research and ultimately employ in excess of 2,000 people.

The university is also a major contributor to the medical field with the EKG and the gastroscope. The university’s 13,000-acre (53 km^2) biological station in the Northern Lower Peninsula of Michigan is one of only 47 Biosphere Reserves in the United States.

In the mid-1960s U-M researchers worked with IBM to develop a new virtual memory architectural model that became part of IBM’s Model 360/67 mainframe computer (the 360/67 was initially dubbed the 360/65M where the “M” stood for Michigan). The Michigan Terminal System (MTS), an early time-sharing computer operating system developed at U-M, was the first system outside of IBM to use the 360/67’s virtual memory features.

U-M is home to the National Election Studies and the University of Michigan Consumer Sentiment Index. The Correlates of War project, also located at U-M, is an accumulation of scientific knowledge about war. The university is also home to major research centers in optics, reconfigurable manufacturing systems, wireless integrated microsystems, and social sciences. The University of Michigan Transportation Research Institute and the Life Sciences Institute are located at the university. The Institute for Social Research (ISR), the nation’s longest-standing laboratory for interdisciplinary research in the social sciences, is home to the Survey Research Center, Research Center for Group Dynamics, Center for Political Studies, Population Studies Center, and Inter-Consortium for Political and Social Research. Undergraduate students are able to participate in various research projects through the Undergraduate Research Opportunity Program (UROP) as well as the UROP/Creative-Programs.

The U-M library system comprises nineteen individual libraries with twenty-four separate collections—roughly 13.3 million volumes. U-M was the original home of the JSTOR database, which contains about 750,000 digitized pages from the entire pre-1990 backfile of ten journals of history and economics, and has initiated a book digitization program in collaboration with Google. The University of Michigan Press is also a part of the U-M library system.

In the late 1960s U-M, together with Michigan State University and Wayne State University, founded the Merit Network, one of the first university computer networks. The Merit Network was then and remains today administratively hosted by U-M. Another major contribution took place in 1987 when a proposal submitted by the Merit Network together with its partners IBM, MCI, and the State of Michigan won a national competition to upgrade and expand the National Science Foundation Network (NSFNET) backbone from 56,000 to 1.5 million, and later to 45 million bits per second. In 2006, U-M joined with Michigan State University and Wayne State University to create the the University Research Corridor. This effort was undertaken to highlight the capabilities of the state’s three leading research institutions and drive the transformation of Michigan’s economy. The three universities are electronically interconnected via the Michigan LambdaRail (MiLR, pronounced ‘MY-lar’), a high-speed data network providing 10 Gbit/s connections between the three university campuses and other national and international network connection points in Chicago.

From The National Institute of Standards and Technology: “Unveiling the Universe – In Four New Studies NIST Explores Novel Ways to Hunt Dark Matter”

From The National Institute of Standards and Technology

12.8.22

Media Contact
Rich Press
richard.press@nist.gov
(301) 975-0501

Technical Contact
Jacob Taylor
jacob.taylor@nist.gov
(301) 975-8586

Marianna Safronova
marianna.safronova@nist.gov

For decades, astronomers and physicists have been trying to solve one of the deepest mysteries about the cosmos: An estimated 85% of its mass is missing. Numerous astronomical observations indicate that the visible mass in the universe is not nearly enough to hold galaxies together and account for how matter clumps. Some kind of invisible, unknown type of subatomic particle, dubbed dark matter, must provide the extra gravitational glue.

In underground laboratories and at particle accelerators, scientists have been searching for this dark matter with no success for more than 30 years.
__________________________________
Dark Matter Background
Fritz Zwicky discovered Dark Matter in the 1930s when observing the movement of the Coma Cluster., and Vera Rubin a Woman in STEM, denied the Nobel, some 30 years later, did most of the work on Dark Matter.

Fritz Zwicky.

Coma cluster via NASA/ESA Hubble, the original example of Dark Matter discovered during observations by Fritz Zwicky and confirmed 30 years later by Vera Rubin.

In modern times, it was astronomer Fritz Zwicky, in the 1930s, who made the first observations of what we now call dark matter. His 1933 observations of the Coma Cluster of galaxies seemed to indicated it has a mass 500 times more than that previously calculated by Edwin Hubble. Furthermore, this extra mass seemed to be completely invisible. Although Zwicky’s observations were initially met with much skepticism, they were later confirmed by other groups of astronomers.

Thirty years later, astronomer Vera Rubin provided a huge piece of evidence for the existence of dark matter. She discovered that the centers of galaxies rotate at the same speed as their extremities, whereas, of course, they should rotate faster. Think of a vinyl LP on a record deck: its center rotates faster than its edge. That’s what logic dictates we should see in galaxies too. But we do not. The only way to explain this is if the whole galaxy is only the center of some much larger structure, as if it is only the label on the LP so to speak, causing the galaxy to have a consistent rotation speed from center to edge.

Vera Rubin, following Zwicky, postulated that the missing structure in galaxies is dark matter. Her ideas were met with much resistance from the astronomical community, but her observations have been confirmed and are seen today as pivotal proof of the existence of dark matter.

Astronomer Vera Rubin at the Lowell Observatory in 1965, worked on Dark Matter (The Carnegie Institution for Science).

Vera Rubin, with Department of Terrestrial Magnetism (DTM) image tube spectrograph attached to the Kitt Peak 84-inch telescope, 1970.

Vera Rubin measuring spectra, worked on Dark Matter(Emilio Segre Visual Archives AIP SPL).

Dark Matter Research

Super Cryogenic Dark Matter Search from DOE’s SLAC National Accelerator Laboratory at Stanford University at SNOLAB (Vale Inco Mine, Sudbury, Canada).

LBNL LZ Dark Matter Experiment xenon detector at Sanford Underground Research Facility Credit: Matt Kapust.

Lambda Cold Dark Matter Expansion ΛCDM of the Universe. Credit Alex Mittelmann Coldcreation.

DAMA at Gran Sasso uses sodium iodide housed in copper to hunt for dark matter LNGS-INFN.

Yale HAYSTAC axion dark matter experiment at Yale’s Wright Lab.

DEAP Dark Matter detector, The DEAP-3600, suspended in the SNOLAB (CA) deep in Sudbury’s Creighton Mine.

The LBNL LZ Dark Matter Experiment Dark Matter project at SURF, Lead, SD.

DAMA-LIBRA Dark Matter experiment at the Italian National Institute for Nuclear Physics’ (INFN’s) Gran Sasso National Laboratories (LNGS) located in the Abruzzo region of central Italy.

DARWIN Dark Matter experiment. A design study for a next-generation, multi-ton dark matter detector in Europe at The University of Zurich [Universität Zürich](CH).

PandaX II Dark Matter experiment at Jin-ping Underground Laboratory (CJPL) in Sichuan, China.

Inside the Axion Dark Matter eXperiment U Washington. Credit: Mark Stone U. of Washington. Axion Dark Matter Experiment.

XENONnT experiment at the Laboratori Nazionali del Gran Sasso (LNGS) underground laboratory in Italy.

The University of Western Australia ORGAN Experiment’s main detector. A small copper cylinder called a “resonant cavity” traps photons generated during dark matter conversion. The cylinder is bolted to a “dilution refrigerator” which cools the experiment to very low temperatures.
__________________________________

Researchers at NIST are now exploring new ways to search for the invisible particles. In one study, a prototype for a much larger experiment, researchers have used state-of-the-art superconducting detectors to hunt for dark matter. The study has already placed new limits on the possible mass of one type of hypothesized dark matter. Another NIST team has proposed that trapped electrons, commonly used to measure properties of ordinary particles, could also serve as highly sensitive detectors of hypothetical dark matter particles if they carry charge.

In the superconducting detector study, NIST scientists Jeff Chiles and Sae Woo Nam and their collaborators used tungsten silicide superconducting nanowires only one-thousandth the width of a human hair as dark-matter detectors.

NIST scientists Jeff Chiles and Sae Woo Nam and their collaborators used tungsten silicide superconducting nanowires only one-thousandth the width of a human hair as dark-matter detectors.

“Superconducting” refers to a property that some materials, such as tungsten silicide, have at ultralow temperatures: zero resistance to the flow of electrical current. Systems of such wires, formally known as superconducting nanowire single-photon detectors (SNSPDs), are exquisitely sensitive to extremely small amounts of energy imparted by photons (particles of light) and perhaps dark matter particles when they collide with the detectors.

Although the experiment would have to be performed on a larger scale with many more detectors to provide an expanded dataset, it is still the most sensitive search for dark photons performed to date in this mass range, Nam said. The researchers, including collaborators from the Massachusetts Institute of Technology, Stanford University, University of Washington, New York University and the Flatiron Institute, reported their results in an article in Physical Review Letters [below] posted on June 10.

In a second report, some of the same NIST researchers and their collaborators analyzed data from the first study in a different way. The scientists ignored potential effects of the stack of insulating material and focused only on whether any kind of dark matter particles would be capable of interacting with individual electrons in the nanowire detector itself — either by scattering off an electron or being absorbed by it. Although small, this study has placed the strongest limits of any experiment to date — excluding astrophysical searches and studies of the sun — on the strength of interactions between electrons and dark matter in the sub-million-eV mass range. That makes it likely that a scaled-up version of the SNSPD setup could make a significant contribution to the search for dark matter, said Chiles. He and his colleagues from the Hebrew University of Jerusalem, the University of California-Santa Cruz, the University of California’s Santa Cruz Institute for Particle Physics; and MIT reported this analysis in an article in the Dec. 8 edition of Physical Review D [below].

In a third study, a NIST physicist and his colleagues proposed that single electrons, electromagnetically confined to a small region of space, could be sensitive detectors of charged dark matter particles. For more than three decades, scientists have used a much heavier population of positively charged beryllium ions to probe the electric and magnetic properties of ordinary (non-dark) charged particles. Electrons, however, would make ideal detectors for sensing dark matter particles if those particles have even the slightest electric charge. That’s because electrons have the lowest mass of any charged particle known and therefore are easily pushed or pulled by the merest electrical disturbance, such as a particle with a small electric charge passing nearby. Only a few single trapped electrons would be needed to detect charged dark matter particles with only one-hundredth the charge of an electron, said NIST physicist Jake Taylor, a fellow of the Joint Quantum Institute and the Joint Center for Quantum Information and Computer Science, research partnerships between NIST and the University of Maryland. The electromagnetically trapped electrons would be cooled to a fraction of a degree above absolute zero in order to limit the particle’s inherent jitter. Taylor, along with Daniel Carney of The DOE’s Lawrence Berkeley National Laboratory in California, Hartmut Haffner of the University of California- Berkeley, and David C. Moore of Yale University, described their proposed experiment in a Physical Review Letters [below] article posted online last August. By configuring the trap so that the strength of the electron’s confinement is different along each dimension — length, width and height — the trap could potentially also provide information about the direction from which the dark matter particle arrived. However, scientists must grapple with a technological challenge before they can employ electron trapping to search for dark matter. Photons are used to cool, manipulate and sense the motion of trapped ions and electrons. For beryllium ions, those photons — generated by a laser — fall in the range of visible light. The technology that enables visible-light photons to manipulate trapped beryllium ions is well established. In contrast, the photons required to sense the motion of single electrons have microwave energies, and the necessary detection technology has yet to be perfected. However, if interest in the project is strong enough, scientists might develop an electron trap capable of detecting dark matter in less than five years, Carney estimated.

In the fourth study, a NIST researcher and an international group of colleagues are looking beyond Earth to hunt for dark matter. A team that includes Marianna Safronova of the University of Delaware and the Joint Quantum Institute has proposed that a new generation of atomic clocks, installed on a spacecraft that would fly closer to the Sun than Mercury’s orbit, could search for signs of ultralight dark matter. This hypothetical type of dark matter, bound to a halo surrounding the Sun, would cause tiny variations in the fundamental constants of nature, including the mass of the electron and the fine structure constant. Changes in these constants would alter the frequency at which atomic clocks vibrate — the rate at which they “tick.” Among the large variety of atomic clocks, researchers would carefully choose two that have different sensitivities to changes in the fundamental constants driven by ultralight dark matter. By measuring the ratio of the two varying frequencies, scientists could reveal the presence of the dark matter, the researchers calculated. They describe their analysis in an article posted online Dec. 5 in Nature Astronomy [below].

Science papers:
Physical Review Letters
Physical Review D
Physical Review Letters 2021
Nature Astronomy

See the full article here.

Comments are invited and will be appreciated, especially if the reader finds any errors which I can correct. Use “Reply”.

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Please help promote STEM in your local schools.

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NIST Campus, Gaitherberg, MD.

The National Institute of Standards and Technology‘s Mission, Vision, Core Competencies, and Core Values

Mission

To promote U.S. innovation and industrial competitiveness by advancing measurement science, standards, and technology in ways that enhance economic security and improve our quality of life.

NIST’s vision

NIST will be the world’s leader in creating critical measurement solutions and promoting equitable standards. Our efforts stimulate innovation, foster industrial competitiveness, and improve the quality of life.

NIST’s core competencies

Measurement science
Rigorous traceability
Development and use of standards

NIST’s core values

NIST is an organization with strong values, reflected both in our history and our current work. NIST leadership and staff will uphold these values to ensure a high performing environment that is safe and respectful of all.

Perseverance: We take the long view, planning the future with scientific knowledge and imagination to ensure continued impact and relevance for our stakeholders.
Integrity: We are ethical, honest, independent, and provide an objective perspective.
Inclusivity: We work collaboratively to harness the diversity of people and ideas, both inside and outside of NIST, to attain the best solutions to multidisciplinary challenges.
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Background

The Articles of Confederation, ratified by the colonies in 1781, contained the clause, “The United States in Congress assembled shall also have the sole and exclusive right and power of regulating the alloy and value of coin struck by their own authority, or by that of the respective states—fixing the standards of weights and measures throughout the United States”. Article 1, section 8, of the Constitution of the United States (1789), transferred this power to Congress; “The Congress shall have power…To coin money, regulate the value thereof, and of foreign coin, and fix the standard of weights and measures”.

In January 1790, President George Washington, in his first annual message to Congress stated that, “Uniformity in the currency, weights, and measures of the United States is an object of great importance, and will, I am persuaded, be duly attended to”, and ordered Secretary of State Thomas Jefferson to prepare a plan for Establishing Uniformity in the Coinage, Weights, and Measures of the United States, afterwards referred to as the Jefferson report. On October 25, 1791, Washington appealed a third time to Congress, “A uniformity of the weights and measures of the country is among the important objects submitted to you by the Constitution and if it can be derived from a standard at once invariable and universal, must be no less honorable to the public council than conducive to the public convenience”, but it was not until 1838, that a uniform set of standards was worked out. In 1821, John Quincy Adams had declared “Weights and measures may be ranked among the necessities of life to every individual of human society”.

From 1830 until 1901, the role of overseeing weights and measures was carried out by the Office of Standard Weights and Measures, which was part of the U.S. Coast and Geodetic Survey in the Department of the Treasury.

Bureau of Standards

In 1901 in response to a bill proposed by Congressman James H. Southard (R- Ohio) the National Bureau of Standards was founded with the mandate to provide standard weights and measures and to serve as the national physical laboratory for the United States. (Southard had previously sponsored a bill for metric conversion of the United States.)

President Theodore Roosevelt appointed Samuel W. Stratton as the first director. The budget for the first year of operation was $40,000. The Bureau took custody of the copies of the kilogram and meter bars that were the standards for US measures, and set up a program to provide metrology services for United States scientific and commercial users. A laboratory site was constructed in Washington DC (US) and instruments were acquired from the national physical laboratories of Europe. In addition to weights and measures the Bureau developed instruments for electrical units and for measurement of light. In 1905 a meeting was called that would be the first National Conference on Weights and Measures.

Initially conceived as purely a metrology agency the Bureau of Standards was directed by Herbert Hoover to set up divisions to develop commercial standards for materials and products. Some of these standards were for products intended for government use; but product standards also affected private-sector consumption. Quality standards were developed for products including some types of clothing; automobile brake systems and headlamps; antifreeze; and electrical safety. During World War I, the Bureau worked on multiple problems related to war production even operating its own facility to produce optical glass when European supplies were cut off. Between the wars Harry Diamond of the Bureau developed a blind approach radio aircraft landing system. During World War II military research and development was carried out including development of radio propagation forecast methods; the proximity fuze and the standardized airframe used originally for Project Pigeon; and shortly afterwards the autonomously radar-guided Bat anti-ship guided bomb and the Kingfisher family of torpedo-carrying missiles.

In 1948, financed by the United States Air Force the Bureau began design and construction of SEAC: the Standards Eastern Automatic Computer. The computer went into operation in May 1950 using a combination of vacuum tubes and solid-state diode logic. About the same time the Standards Western Automatic Computer, was built at the Los Angeles office of the NBS by Harry Huskey and used for research there. A mobile version- DYSEAC- was built for the Signal Corps in 1954.

Due to a changing mission, the “National Bureau of Standards” became the “ The National Institute of Standards and Technology” in 1988.

Following September 11, 2001, NIST conducted the official investigation into the collapse of the World Trade Center buildings.

Organization

NIST is headquartered in Gaithersburg, Maryland, and operates a facility in Boulder, Colorado, which was dedicated by President Eisenhower in 1954. NIST’s activities are organized into laboratory programs and extramural programs. Effective October 1, 2010, NIST was realigned by reducing the number of NIST laboratory units from ten to six. NIST Laboratories include:

Communications Technology Laboratory (CTL)
Engineering Laboratory (EL)
Information Technology Laboratory (ITL)
Center for Neutron Research (NCNR)
Material Measurement Laboratory (MML)
Physical Measurement Laboratory (PML)

Extramural programs include:

Hollings Manufacturing Extension Partnership (MEP), a nationwide network of centers to assist small and mid-sized manufacturers to create and retain jobs, improve efficiencies, and minimize waste through process improvements and to increase market penetration with innovation and growth strategies;
Technology Innovation Program (TIP), a grant program where NIST and industry partners cost share the early-stage development of innovative but high-risk technologies;
Baldrige Performance Excellence Program, which administers the Malcolm Baldrige National Quality Award, the nation’s highest award for performance and business excellence.

NIST’s Boulder laboratories are best known for NIST‑F1 which houses an atomic clock.

NIST-F1 Atomic Clock

NIST‑F1 serves as the source of the nation’s official time. From its measurement of the natural resonance frequency of cesium—which defines the second—NIST broadcasts time signals via longwave radio station WWVB near Fort Collins in Colorado, and shortwave radio stations WWV and WWVH, located near Fort Collins and Kekaha in Hawai’i, respectively.

NIST also operates a neutron science user facility: the NIST Center for Neutron Research (NCNR).

NIST Center for Neutron Research

The NCNR provides scientists access to a variety of neutron scattering instruments which they use in many research fields (materials science; fuel cells; biotechnology etc.).

The SURF III Synchrotron Ultraviolet Radiation Facility is a source of synchrotron radiation in continuous operation since 1961.

NIST SURF III Synchrotron Ultraviolet Radiation Facility

SURF III now serves as the US national standard for source-based radiometry throughout the generalized optical spectrum. All NASA-borne extreme-ultraviolet observation instruments have been calibrated at SURF since the 1970s, and SURF is used for measurement and characterization of systems for extreme ultraviolet lithography.

The Center for Nanoscale Science and Technology performs research in nanotechnology, both through internal research efforts and by running a user-accessible cleanroom nanomanufacturing facility.

NIST Center for Nanoscale Science and Technology

This “NanoFab” is equipped with tools for lithographic patterning and imaging (e.g., electron microscopes and atomic force microscopes).
Committees

NIST has seven standing committees:

Technical Guidelines Development Committee (TGDC)
Advisory Committee on Earthquake Hazards Reduction (ACEHR)
National Construction Safety Team Advisory Committee (NCST Advisory Committee)
Information Security and Privacy Advisory Board (ISPAB)
Visiting Committee on Advanced Technology (VCAT)
Board of Overseers for the Malcolm Baldrige National Quality Award (MBNQA Board of Overseers)
Manufacturing Extension Partnership National Advisory Board (MEPNAB)

Measurements and standards

As part of its mission, NIST supplies industry, academia, government, and other users with over 1,300 Standard Reference Materials (SRMs). These artifacts are certified as having specific characteristics or component content, used as calibration standards for measuring equipment and procedures, quality control benchmarks for industrial processes, and experimental control samples.

Handbook 44

NIST publishes the Handbook 44 each year after the annual meeting of the National Conference on Weights and Measures (NCWM). Each edition is developed through cooperation of the Committee on Specifications and Tolerances of the NCWM and the Weights and Measures Division (WMD) of the NIST. The purpose of the book is a partial fulfillment of the statutory responsibility for “cooperation with the states in securing uniformity of weights and measures laws and methods of inspection”.

NIST has been publishing various forms of what is now the Handbook 44 since 1918 and began publication under the current name in 1949. The 2010 edition conforms to the concept of the primary use of the SI (metric) measurements recommended by the Omnibus Foreign Trade and Competitiveness Act of 1988.

From “The Harvard Gazette” : “Mystery of dark matter — and search for WIMP”

From “The Harvard Gazette”

At

Harvard University

10.26.22
Clea Simon

MIT physicist on mystery of dark matter

Peter Fisher. © Justin Knight.

MIT physicist Peter Fisher showed a slide of the Andromeda galaxy, with its lush swirl of stars emanating out in a flat disc, containing roughly a trillion stars. Photo by Jon Chase/Harvard Staff Photographer.

Scientists know that dark matter exists because although we can’t see it, we can see the effects of what it does in the world, sort of like a ghost bumping around a haunted house. And we’re not sure what it is, but some think it may just be a WIMP (weakly interacting massive particle).

Those are some of the insights that emerged from a Harvard Science Book Talk on Monday that featured an online conversation between Peter Fisher, the Thomas A. Frank Professor of Physics at MIT, who just wrote a book titled What Is Dark Matter?, and Melissa Franklin, Mallinckrodt Professor of Physics at Harvard.

Fisher opened the event, sponsored by the Harvard Division of Science, Harvard Library, and Harvard Book Store, with a short response to the question the title poses: “The answer is we don’t know.” He offered several possibilities, explaining that his subject could be a particle, a heavy particle, “tiny black holes from the beginning of the universe, or it could be something we haven’t even thought of.”

To shed some light on the topic, Fisher recounted the history of particle physics, from the invention of quantum mechanics in the 1930s to the development of the standard model theory in the 1990s, which explains three out of four known fundamental forces (electromagnetic, weak and strong interactions, but not gravity).

Standard Model of Particle Physics, Quantum Diaries.

Parallel to the development of this science, astronomers studying the universe were making discoveries about the movement of the stars away from the Earth — proof the universe is expanding. That movement, astronomers realized, was happening faster than forces such as the gravity of the component stars could explain. “They studied the way galaxies moved with respect to each other, and the way stars moved within galaxies. And the only way they could come up with explaining how everything was moving in the biggest scales of the universe was the introduction of matter that we couldn’t see,” he said.

The answer, requiring all these disciplines, was that there “were actually two kinds of matter that we couldn’t see.” These were dark energy and dark matter. “Dark matter makes particles or stars within galaxies move more quickly than you’d expect from the mass in those galaxies,” he said.

To illustrate, Fisher shared a slide of the Andromeda galaxy, with its lush swirl of stars emanating out in a flat disc. “It looks very similar to the Milky Way in the middle,” he said, pointing out the “glowing region in the very middle of that: a big black hole about a million times the mass of our sun. There’s a lot of matter being pulled into the dense central region, and you can see there’s this beautiful pancake shape with spiral arms,” containing roughly a trillion stars.

“What’s particularly interesting is you can see that there’s a sharp end to the disc part. And that edge is really only explainable if you hypothesize that there is some substance called dark matter that is making a gravitational pull that makes that shape.”

Andromeda is not unique. In fact, Fisher explained, images of deep space provided by the Hubble Space Telescope reveal a striking consistency. “There have been very detailed measurements of literally thousands of galaxies, and they all share the same features,” he said. “A careful study of all these different kinds of galaxies always comes up with the same conclusion, which is the stars are moving too fast to be explainable by the amount of light coming from that galaxy,” he said. “This must denote the presence of dark matter around the galaxy.”

Franklin, paraphrasing Fisher’s book, likened the search to a ghost hunt. “If you have ghosts in your house moving things around, you can’t see them or hear them or feel them. So what you want to do is figure out from the movements what exactly is going on.”

What dark matter is, however, is much less clear. One theory is that it is a new kind of particle, a weakly interacting massive particle (or WIMP). If that theory is correct, said Fisher, dark matter is likely all around — but “here on Earth, it’s hard to find dark matter because there’s so much normal matter around. You have to look and think about galaxies as a whole” in order to get a large enough scale to study dark matter.

Another theory is that dark matter is primordial black holes, dating back to the origins of the universe. If that’s the case, Fisher noted, these “tiny” bits of matter “could just go straight through the Earth. They don’t pick up much matter. They can go straight through pretty much anything and nobody really notices it.”

The ongoing search, Fisher cautioned, will require continuing advancements in technology but also caution and a careful understanding of how our tools work. To illustrate what can go wrong, he described the nation’s Distant Early Warning Line, a system of radar stations along the Arctic Circle created as a defense against a possible Soviet missile attack during the Cold War. “These radar operators saw all kinds of stuff that it took years to explain,” he said, resulting in theories about UFOs that are still around. “Anytime you build a new device, you see things you don’t expect.”

As the search for dark matter continues, such meticulous discipline is vital. However, despite the many questions that remain, we can be confident that dark matter exists because “all of the measurements are made repeatedly using very different kinds of telescopes,” he said. The movement of stars, for example, has been observed with large optical telescopes and also radio telescopes. “It’s not a guarantee, but it gives one confidence that the same overall effect is observed in two very different ways.”

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Dark Matter Background
Fritz Zwicky discovered Dark Matter in the 1930s when observing the movement of the Coma Cluster., and Vera Rubin a Woman in STEM, denied the Nobel, some 30 years later, did most of the work on Dark Matter.

Fritz Zwicky.
Coma cluster via NASA/ESA Hubble, the original example of Dark Matter discovered during observations by Fritz Zwicky and confirmed 30 years later by Vera Rubin.

In modern times, it was astronomer Fritz Zwicky, in the 1930s, who made the first observations of what we now call dark matter. His 1933 observations of the Coma Cluster of galaxies seemed to indicated it has a mass 500 times more than that previously calculated by Edwin Hubble. Furthermore, this extra mass seemed to be completely invisible. Although Zwicky’s observations were initially met with much skepticism, they were later confirmed by other groups of astronomers.

Thirty years later, astronomer Vera Rubin provided a huge piece of evidence for the existence of dark matter. She discovered that the centers of galaxies rotate at the same speed as their extremities, whereas, of course, they should rotate faster. Think of a vinyl LP on a record deck: its center rotates faster than its edge. That’s what logic dictates we should see in galaxies too. But we do not. The only way to explain this is if the whole galaxy is only the center of some much larger structure, as if it is only the label on the LP so to speak, causing the galaxy to have a consistent rotation speed from center to edge.

Vera Rubin, following Zwicky, postulated that the missing structure in galaxies is dark matter. Her ideas were met with much resistance from the astronomical community, but her observations have been confirmed and are seen today as pivotal proof of the existence of dark matter.
Astronomer Vera Rubin at the Lowell Observatory in 1965, worked on Dark Matter (The Carnegie Institution for Science).

Vera Rubin, with Department of Terrestrial Magnetism (DTM) image tube spectrograph attached to the Kitt Peak 84-inch telescope, 1970.

Vera Rubin measuring spectra, worked on Dark Matter(Emilio Segre Visual Archives AIP SPL).

Dark Matter Research

Super Cryogenic Dark Matter Search from DOE’s SLAC National Accelerator Laboratory at Stanford University at SNOLAB (Vale Inco Mine, Sudbury, Canada).

LBNL LZ Dark Matter Experiment xenon detector at Sanford Underground Research Facility Credit: Matt Kapust.

Lambda Cold Dark Matter Expansion ΛCDM of the Universe. Credit Alex Mittelmann Coldcreation.

DAMA at Gran Sasso uses sodium iodide housed in copper to hunt for dark matter LNGS-INFN.

Yale HAYSTAC axion dark matter experiment at Yale’s Wright Lab.

DEAP Dark Matter detector, The DEAP-3600, suspended in the SNOLAB (CA) deep in Sudbury’s Creighton Mine.

The LBNL LZ Dark Matter Experiment Dark Matter project at SURF, Lead, SD.

DAMA-LIBRA Dark Matter experiment at the Italian National Institute for Nuclear Physics’ (INFN’s) Gran Sasso National Laboratories (LNGS) located in the Abruzzo region of central Italy.

DARWIN Dark Matter experiment. A design study for a next-generation, multi-ton dark matter detector in Europe at The University of Zurich [Universität Zürich](CH).

PandaX II Dark Matter experiment at Jin-ping Underground Laboratory (CJPL) in Sichuan, China.

Inside the Axion Dark Matter eXperiment U Washington (US) Credit : Mark Stone U. of Washington. Axion Dark Matter Experiment.

XENONnT experiment at the Laboratori Nazionali del Gran Sasso (LNGS) underground laboratory in Italy.

The University of Western Australia ORGAN Experiment’s main detector. A small copper cylinder called a “resonant cavity” traps photons generated during dark matter conversion. The cylinder is bolted to a “dilution refrigerator” which cools the experiment to very low temperatures.
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See the full article here .

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Please help promote STEM in your local schools.

Stem Education Coalition

Harvard University is the oldest institution of higher education in the United States, established in 1636 by vote of the Great and General Court of the Massachusetts Bay Colony. It was named after the College’s first benefactor, the young minister John Harvard of Charlestown, who upon his death in 1638 left his library and half his estate to the institution. A statue of John Harvard stands today in front of University Hall in Harvard Yard, and is perhaps the University’s best-known landmark.

Harvard University has 12 degree-granting Schools in addition to the Radcliffe Institute for Advanced Study. The University has grown from nine students with a single master to an enrollment of more than 20,000 degree candidates including undergraduate, graduate, and professional students. There are more than 360,000 living alumni in the U.S. and over 190 other countries.

The Massachusetts colonial legislature, the General Court, authorized Harvard University’s founding. In its early years, Harvard College primarily trained Congregational and Unitarian clergy, although it has never been formally affiliated with any denomination. Its curriculum and student body were gradually secularized during the 18th century, and by the 19th century, Harvard University (US) had emerged as the central cultural establishment among the Boston elite. Following the American Civil War, President Charles William Eliot’s long tenure (1869–1909) transformed the college and affiliated professional schools into a modern research university; Harvard became a founding member of the Association of American Universities in 1900. James B. Conant led the university through the Great Depression and World War II; he liberalized admissions after the war.

The university is composed of ten academic faculties plus the Radcliffe Institute for Advanced Study. Arts and Sciences offers study in a wide range of academic disciplines for undergraduates and for graduates, while the other faculties offer only graduate degrees, mostly professional. Harvard has three main campuses: the 209-acre (85 ha) Cambridge campus centered on Harvard Yard; an adjoining campus immediately across the Charles River in the Allston neighborhood of Boston; and the medical campus in Boston’s Longwood Medical Area. Harvard University’s endowment is valued at $41.9 billion, making it the largest of any academic institution. Endowment income helps enable the undergraduate college to admit students regardless of financial need and provide generous financial aid with no loans The Harvard Library is the world’s largest academic library system, comprising 79 individual libraries holding about 20.4 million items.

Harvard University has more alumni, faculty, and researchers who have won Nobel Prizes (161) and Fields Medals (18) than any other university in the world and more alumni who have been members of the U.S. Congress, MacArthur Fellows, Rhodes Scholars (375), and Marshall Scholars (255) than any other university in the United States. Its alumni also include eight U.S. presidents and 188 living billionaires, the most of any university. Fourteen Turing Award laureates have been Harvard affiliates. Students and alumni have also won 10 Academy Awards, 48 Pulitzer Prizes, and 108 Olympic medals (46 gold), and they have founded many notable companies.

Colonial

Harvard University was established in 1636 by vote of the Great and General Court of the Massachusetts Bay Colony. In 1638, it acquired British North America’s first known printing press. In 1639, it was named Harvard College after deceased clergyman John Harvard, an alumnus of the University of Cambridge(UK) who had left the school £779 and his library of some 400 volumes. The charter creating the Harvard Corporation was granted in 1650.

A 1643 publication gave the school’s purpose as “to advance learning and perpetuate it to posterity, dreading to leave an illiterate ministry to the churches when our present ministers shall lie in the dust.” It trained many Puritan ministers in its early years and offered a classic curriculum based on the English university model—many leaders in the colony had attended the University of Cambridge—but conformed to the tenets of Puritanism. Harvard University has never affiliated with any particular denomination, though many of its earliest graduates went on to become clergymen in Congregational and Unitarian churches.

Increase Mather served as president from 1681 to 1701. In 1708, John Leverett became the first president who was not also a clergyman, marking a turning of the college away from Puritanism and toward intellectual independence.

19th century

In the 19th century, Enlightenment ideas of reason and free will were widespread among Congregational ministers, putting those ministers and their congregations in tension with more traditionalist, Calvinist parties. When Hollis Professor of Divinity David Tappan died in 1803 and President Joseph Willard died a year later, a struggle broke out over their replacements. Henry Ware was elected to the Hollis chair in 1805, and the liberal Samuel Webber was appointed to the presidency two years later, signaling the shift from the dominance of traditional ideas at Harvard to the dominance of liberal, Arminian ideas.

Charles William Eliot, president 1869–1909, eliminated the favored position of Christianity from the curriculum while opening it to student self-direction. Though Eliot was the crucial figure in the secularization of American higher education, he was motivated not by a desire to secularize education but by Transcendentalist Unitarian convictions influenced by William Ellery Channing and Ralph Waldo Emerson.

20th century

In the 20th century, Harvard University’s reputation grew as a burgeoning endowment and prominent professors expanded the university’s scope. Rapid enrollment growth continued as new graduate schools were begun and the undergraduate college expanded. Radcliffe College, established in 1879 as the female counterpart of Harvard College, became one of the most prominent schools for women in the United States. Harvard University became a founding member of the Association of American Universities in 1900.

The student body in the early decades of the century was predominantly “old-stock, high-status Protestants, especially Episcopalians, Congregationalists, and Presbyterians.” A 1923 proposal by President A. Lawrence Lowell that Jews be limited to 15% of undergraduates was rejected, but Lowell did ban blacks from freshman dormitories.

President James B. Conant reinvigorated creative scholarship to guarantee Harvard University’s preeminence among research institutions. He saw higher education as a vehicle of opportunity for the talented rather than an entitlement for the wealthy, so Conant devised programs to identify, recruit, and support talented youth. In 1943, he asked the faculty to make a definitive statement about what general education ought to be, at the secondary as well as at the college level. The resulting Report, published in 1945, was one of the most influential manifestos in 20th century American education.

Between 1945 and 1960, admissions were opened up to bring in a more diverse group of students. No longer drawing mostly from select New England prep schools, the undergraduate college became accessible to striving middle class students from public schools; many more Jews and Catholics were admitted, but few blacks, Hispanics, or Asians. Throughout the rest of the 20th century, Harvard became more diverse.

Harvard University’s graduate schools began admitting women in small numbers in the late 19th century. During World War II, students at Radcliffe College (which since 1879 had been paying Harvard University professors to repeat their lectures for women) began attending Harvard University classes alongside men. Women were first admitted to the medical school in 1945. Since 1971, Harvard University has controlled essentially all aspects of undergraduate admission, instruction, and housing for Radcliffe women. In 1999, Radcliffe was formally merged into Harvard University.

21st century

Drew Gilpin Faust, previously the dean of the Radcliffe Institute for Advanced Study, became Harvard University’s first woman president on July 1, 2007. She was succeeded by Lawrence Bacow on July 1, 2018.

From The University of Melbourne (AU) Via “COSMOS (AU)” : “Underground ‘genius lab’ one step closer to finding dark matter”

From The University of Melbourne (AU)

Via

“COSMOS (AU)”

8.19.22
Jacinta Bowler

A black (mine) hole in central Victoria ready to swallow up the equipment…

The Stawell Underground Physics Laboratory 1km underground. Credit Olivia Gumienny/University of Melbourne.

An experiment to search for dark matter, which will take place in a gold mine under the Victorian town of Stawell, has just completed the first stage of its plans.

Stage one of the Stawell Underground Physics Laboratory (SUPL) was officially opened today. Although there’s no detector or other equipment yet in the new space, the once cave like structure now looks like a shiny new laboratory, equipped with working showers and air-conditioning.

The lab, located in the active Stawell Gold Mine, is 1-kilometre underground and includes a research hall 33 metres long, 10 metres wide and 12.3 metres high.

“We know there is much more matter in the universe than we can see,” says Professor Elisabetta Barberio from the University of Melbourne.

“With the Stawell Underground Physics Laboratory, we have the tools and location to detect this dark matter. Proving the existence of dark matter will help us understand its nature and forever change how we see the universe.”

The lab has now been handed over to the Stawell Underground Physics Laboratory team who will start bringing in equipment in the next month.

This may take a while, as the detector is housed in tonnes of steel that need to be brought down the long, winding tunnel in the mine itself.

The experiment has been marred by delays. The original project was set to be finished in the mid-2010s, and even last year there were hopes of getting it finished by the end of 2021.

However, with the lab finally complete, it hopefully won’t be too long until they start trying to detect the mysterious particles which seem to make up our Universe.

Also from “COSMOS (AU)”

“Genius lair: Australia’s dark matter experiment underfoot”

8.20.21
Jacinta Bowler

Photo credit: The ARC Centre of Excellence for Dark Matter Particle

Deep in a gold mine on the outskirts of the small Victorian country town of Stawell, several hours’ drive to the north-west of Melbourne, a lab is being built to find one of the universe’s most elusive substances: dark matter.

The lab, located a kilometre underground, currently looks more like a tennis-court sized cave than a multi-million-dollar operation. That’s because the lab – a partnership between the University of Melbourne, ANSTO, Swinburne and more – is still very much a work in progress. But if successful in its quest it could help solve one of the greatest mysteries of astrophysics.

“It’s crunch time for us,” says University of Melbourne Associate Professor Phillip Urquijo, a particle physicist and a technical coordinator of the dark matter experiment, called SABRE – the Sodium Iodide with Active Background Rejection Experiment.

“The lab itself should be completed by December. We’re hoping by November we can start bringing in some of our experimental equipment.”

For something that is thought to make up 85% of the matter in the universe, dark matter hasn’t been easy to find. It can’t be seen in any of the wavelengths that would normally be used to detect space stuff like gas and dust. In fact, it doesn’t seem to interact with electromagnetic force at all – meaning it doesn’t absorb, reflect or emit any type of light.

Scientists only know it exists because stars, galaxies and galaxy clusters have way too much gravitational pull without some further explanation, such as a bunch of dark matter hiding somewhere.

“If we manage to find it, that’s a guaranteed Nobel Prize,” says ANSTO strategic projects senior advisor Dr Richard Garrett. “It’s like [gravitational] waves. That’s another thing they were looking for for 30 to 40 years until, finally, these enormous experiments (namely, the Laser Interferometer Gravitational-Wave Observatory) found it.”

But the search to detect dark matter has so far been lacklustre. Until now.

Underneath our noses

There’s a couple of different ways researchers have been trying to detect dark matter on Earth.

The first attempts to catch dark matter decaying into something we can detect, like gamma rays or particle-antiparticle pairs. Unfortunately, dark matter isn’t the only astronomical process that produces these, adding another layer of difficulty to the process.

Then there are detectors like SABRE, which try to detect the recoil of a type of hypothetical dark matter particle – called weakly interacting massive particles, or WIMPS – off targets deep underground.

Cutaway view of a 3D rendering of SABRE. Credit: Michael Mews (The University of Melbourne, SABRE member)

But every single detector built has so far only been able to find signals that could be attributed to another cause. Dark matter has stayed obscured.

With one exception. For the last 25 years, a detector called DAMA/LIBRA under the Laboratori Nazionali del Gran Sasso, near L’Aquila central-eastern Italy, has been noting a yearly pattern in the number of signals they capture. Called an “annual modulation effect”, the team believe it could be due to Earth moving closer to and further away from our galaxy’s dark matter halo.

DAMA LIBRA Dark Matter Experiment 1.5 km beneath Italy’s Gran Sasso mountain located in the Abruzzo region of central Italy.

Caterpillar Project A Milky Way size Dark Matter halo and its subhalos circled, an enormous suite of simulations. Griffen et al. 2016.

“Over those 25 years, the data [at DAMA/LIBRA] showed that it has this annual modulation effect with extremely, extremely high levels of significance,” says Urquijo. “Through their studies, and through independent reviews of their studies, they couldn’t rule out a dark matter hypothesis to explain it.”

The Italian lab has been something of a black sheep of the detector world, as no other detector has been able to replicate their results. One reason for this is due to the particular sodium iodide crystals the DAMA/LIBRA team has used. They were the most radio pure – meaning very low levels of radioactivity – ever made, a record that the team still holds to this day.

The crystals are made by starting with “astrograde” sodium iodide powder – a compound that’s low in radioactivity but not yet a crystal. When researchers grow the crystal from the powder, normally radioactive contaminants from the environment end up tangled in the crystals, and so very specific machinery is needed to grow and refine it while keeping radioactivity low.

“It’s actually a very difficult and time-consuming R&D process that is very, very niche,” says Urquijo about the crystals.

But sceptics of DAMA/LIBRA don’t think it’s to do with the radio purity of the crystals. Because the pattern is detected annually, they propose that the detector is only measuring this variation in signal due to the changing seasons.

That’s where being on the other side of the world with opposite seasons comes in handy.

“If we see the same effect as theirs, we know it’s not a seasonal effect, it’s something external,” says Urquijo. “We’ll both be seeing dark matter, essentially.”

Trying different rocks

Even if it’s not dark matter, it would still be something external to the Earth that scientists don’t know about yet, which would be almost as fascinating as finding dark matter.

But first they have to finish the detector.

So far, they’ve made sodium iodide crystals even more radio pure than the ones in the DAMA/LIBRA experiment – a feat that took a long research and development process between institutions around the world.

The Australian Nuclear Science and Technology Organisation, (ANSTO)(AU) already had facilities set up to test minute levels of radiation and the team are testing all their materials for radioactivity, making sure everything is as low as possible. Small levels of radiation exist all around us – even bananas and human beings, for example, are both a little radioactive. So the team must limit this “normal” radioactivity so that it doesn’t interfere with the detector.

“We’ve been measuring all kinds of sands and gravels and cement powders from all over Australia, trying to find the best concrete mix for the construction,” says Garrett.

“We’re [deep underground] looking for very, very weak signals, but there’s no point doing that if the concrete we use is radioactive.”

Then there’s the location. Working in an active gold mine has many positives. The mining company takes care of all the ventilation and safety management. Plus, the mine workers can transport the scientists in specially designed mine cars through the long winding tunnels all the way down to the lab.

But it has its drawbacks and challenges. The construction of the lab was delayed for almost three years when the mine changed owners and shut down for a while. Plus, the cave has to be vacated every eight hours so the miners can blast for gold.

Diagrams show the SABRE instrument looking a bit like a chandelier inside a vat, encased in a metal vault. The detector itself is the chandelier, hanging down from the top of the vat and filled with 50kg of the radio-pure sodium iodide crystals to detect any tiny hints of radiation.

The vat, which the team call the Veto, is lined with photomultiplier detectors (incredibly sensitive light detectors) dotted throughout, and will be containing linear alkylbenzene – a liquid normally used to make detergent, but in this case used as a “liquid scintillator” that will flash with light when hit with radiation. And then there’s the four-metre-tall vault, which even Urquijo might tell you is a little over the top: SABRE will have something in the region of 100 tonnes of steel shielding the experiment from stray particle radiation that would pollute any potential measurements.

“We were really paranoid about background radiation,” Urquijo explains. “The region of lowest radioactivity you’ll find anywhere in the Southern Hemisphere is right in the middle of those crystals.

“We have to be better because we’re coming second.”

But right now, the detector parts have not yet been moved into the mine – instead, some of this dark matter-finding machinery is sitting in a car park.

“Melbourne Uni doesn’t have a lot of space to store equipment so we’re using our link through ANSTO to just sit [the liquid scintillator] at the car park there,” says Urquijo.

Once the detector is finally set up, there won’t be much to do but sit up on the surface and wait for results. But until then, there’s plenty to keep the team busy.

“Every material comes in and we measure it for radioactivity to see if it’s good enough,” says Garrett.

“It’s a race against time.”

__________________________________
Dark Matter Background
Fritz Zwicky discovered Dark Matter in the 1930s when observing the movement of the Coma Cluster., Vera Rubin a Woman in STEM, denied the Nobel, some 30 years later, did most of the work on Dark Matter.

Fritz Zwicky.
Coma cluster via NASA/ESA Hubble, the original example of Dark Matter discovered during observations by Fritz Zwicky and confirmed 30 years later by Vera Rubin.
In modern times, it was astronomer Fritz Zwicky, in the 1930s, who made the first observations of what we now call dark matter. His 1933 observations of the Coma Cluster of galaxies seemed to indicated it has a mass 500 times more than that previously calculated by Edwin Hubble. Furthermore, this extra mass seemed to be completely invisible. Although Zwicky’s observations were initially met with much skepticism, they were later confirmed by other groups of astronomers.

Thirty years later, astronomer Vera Rubin provided a huge piece of evidence for the existence of dark matter. She discovered that the centers of galaxies rotate at the same speed as their extremities, whereas, of course, they should rotate faster. Think of a vinyl LP on a record deck: its center rotates faster than its edge. That’s what logic dictates we should see in galaxies too. But we do not. The only way to explain this is if the whole galaxy is only the center of some much larger structure, as if it is only the label on the LP so to speak, causing the galaxy to have a consistent rotation speed from center to edge.

Vera Rubin, following Zwicky, postulated that the missing structure in galaxies is dark matter. Her ideas were met with much resistance from the astronomical community, but her observations have been confirmed and are seen today as pivotal proof of the existence of dark matter.
Astronomer Vera Rubin at the Lowell Observatory in 1965, worked on Dark Matter (The Carnegie Institution for Science).

Vera Rubin, with Department of Terrestrial Magnetism (DTM) image tube spectrograph attached to the Kitt Peak 84-inch telescope, 1970.

Vera Rubin measuring spectra, worked on Dark Matter(Emilio Segre Visual Archives AIP SPL).
Dark Matter Research

Super Cryogenic Dark Matter Search from DOE’s SLAC National Accelerator Laboratory at Stanford University at SNOLAB (Vale Inco Mine, Sudbury, Canada).

LBNL LZ Dark Matter Experiment xenon detector at Sanford Underground Research Facility Credit: Matt Kapust.

Lamda Cold Dark Matter Accerated Expansion of The universe http scinotions.com the-cosmic-inflation-suggests-the-existence-of-parallel-universes. Credit: Alex Mittelmann.

DAMA at Gran Sasso uses sodium iodide housed in copper to hunt for dark matter LNGS-INFN.

Yale HAYSTAC axion dark matter experiment at Yale’s Wright Lab.

DEAP Dark Matter detector, The DEAP-3600, suspended in the SNOLAB (CA) deep in Sudbury’s Creighton Mine.

The LBNL LZ Dark Matter Experiment Dark Matter project at SURF, Lead, SD.

DAMA-LIBRA Dark Matter experiment at the Italian National Institute for Nuclear Physics’ (INFN’s) Gran Sasso National Laboratories (LNGS) located in the Abruzzo region of central Italy.

DARWIN Dark Matter experiment. A design study for a next-generation, multi-ton dark matter detector in Europe at The University of Zurich [Universität Zürich](CH).

PandaX II Dark Matter experiment at Jin-ping Underground Laboratory (CJPL) in Sichuan, China.

Inside the Axion Dark Matter eXperiment U Washington (US) Credit : Mark Stone U. of Washington. Axion Dark Matter Experiment.

XENONnT experiment at the Laboratori Nazionali del Gran Sasso (LNGS) underground laboratory in Italy.

The University of Western Australia ORGAN Experiment’s main detector. A small copper cylinder called a “resonant cavity” traps photons generated during dark matter conversion. The cylinder is bolted to a “dilution refrigerator” which cools the experiment to very low temperatures.
__________________________________

See the full article here .

five-ways-keep-your-child-safe-school-shootings
Please help promote STEM in your local schools.

Stem Education Coalition

The University of Melbourne (AU) is an Australian public research university located in Melbourne, Victoria. Founded in 1853, it is Australia’s second oldest university and the oldest in Victoria. Times Higher Education ranks Melbourne as 33rd in the world, while the Academic Ranking of World Universities places Melbourne 44th in the world (both first in Australia).

Melbourne’s main campus is located in Parkville, an inner suburb north of the Melbourne central business district, with several other campuses located across Victoria. Melbourne is a sandstone university and a member of the Group of Eight, Universitas 21 and the Association of Pacific Rim Universities. Since 1872 various residential colleges have become affiliated with the university. There are 12 colleges located on the main campus and in nearby suburbs offering academic, sporting and cultural programs alongside accommodation for Melbourne students and faculty.

Melbourne comprises 11 separate academic units and is associated with numerous institutes and research centres, including the Walter and Eliza Hall Institute of Medical Research, Florey Institute of Neuroscience and Mental Health, the Melbourne Institute of Applied Economic and Social Research and the Grattan Institute. Amongst Melbourne’s 15 graduate schools the Melbourne Business School, the Melbourne Law School and the Melbourne Medical School are particularly well regarded.

Four Australian prime ministers and five governors-general have graduated from Melbourne. Nine Nobel laureates have been students or faculty, the most of any Australian university.

From Nagoya University [名古屋大学] (JP) Via “phys.org” : “Scientists reveal distribution of dark matter around galaxies 12 billion years ago”

From Nagoya University [名古屋大学] (JP)

Via

“phys.org”

August 1, 2022

The radiation residue from the Big Bang, distorted by Dark Matter 12 billion years ago. Credit: Reiko Matsushita.

A collaboration led by scientists at Nagoya University in Japan has investigated the nature of dark matter surrounding galaxies seen as they were 12 billion years ago, billions of years further back in time than ever before. Their findings, published in Physical Review Letters [below], offer the tantalizing possibility that the fundamental rules of cosmology may differ when examining the early history of our universe.

Seeing something that happened such a long time ago is difficult. Because of the finite speed of light, distant galaxies appear not as they are today, but as they were billions of years ago. But even more challenging is observing Dark Matter, which does not emit light.

Consider a distant source galaxy, even further away than the galaxy whose Dark Matter one wants to investigate. The gravitational pull of the foreground galaxy, including its Dark Matter, distorts the surrounding space and time, as predicted by Albert Einstein’s Theory of General Relativity. As the light from the source galaxy travels through this distortion, it bends, changing the apparent shape of the galaxy. The greater the amount of Dark Matter, the greater the distortion. Thus, scientists can measure the amount of Dark Matter around the foreground galaxy (the “lens” galaxy) from the distortion.

However, beyond a certain point scientists encounter a problem. The galaxies in the deepest reaches of the universe are incredibly faint. As a result, the further away from Earth we look, the less effective this technique becomes. The lensing distortion is subtle and difficult to detect in most cases, so many background galaxies are necessary to detect the signal.

Most previous studies have remained stuck at the same limits. Unable to detect enough distant source galaxies to measure the distortion, they could only analyze Dark Matter from no more than 8–10 billion years ago. These limitations left open the question of the distribution of Dark Matter between this time and 13.7 billion years ago, around the beginning of our universe.

To overcome these challenges and observe Dark Matter from the furthest reaches of the universe, a research team led by Hironao Miyatake from Nagoya University, in collaboration with the University of Tokyo, the National Astronomical Observatory of Japan, and Princeton University, used a different source of background light, the microwaves released from the Big Bang itself.

First, using data from the observations of the Subaru Hyper Suprime-Cam Survey (HSC), the team identified 1.5 million lens galaxies using visible light, selected to be seen 12 billion years ago.

NAOJ Subaru Hyper Suprime-Cam

NAOJ Subaru Hyper Suprime-Cam at ATC, annotated

NAOJ/Subaru Telescope at Mauna Kea Hawai’i, altitude 4207 m (13802 ft) above sea level.

Next, to overcome the lack of galaxy light even further away, they employed microwaves from the cosmic microwave background (CMB), the radiation residue from the Big Bang.

CMB per European Space Agency(EU) Planck.

Using microwaves observed by the European Space Agency’s Planck satellite, the team measured how the Dark Matter around the lens galaxies distorted the microwaves.

“Look at Dark Matter around distant galaxies?” asked Professor Masami Ouchi of the University of Tokyo, who made many of the observations. “It was a crazy idea. No one realized we could do this. But after I gave a talk about a large distant galaxy sample, Hironao came to me and said it may be possible to look at Dark Matter around these galaxies with the CMB.”

“Most researchers use source galaxies to measure Dark Matter distribution from the present to eight billion years ago,” added Assistant Professor Yuichi Harikane of the Institute for Cosmic Ray Research, University of Tokyo. “However, we could look further back into the past because we used the more distant CMB to measure Dark Matter. For the first time, we were measuring Dark Matter from almost the earliest moments of the universe.”

After a preliminary analysis, the researchers soon realized that they had a large enough sample to detect the distribution of Dark Matter. Combining the large distant galaxy sample and the lensing distortions in CMB, they detected Dark Matter even further back in time, from 12 billion years ago. This is only 1.7 billion years after the beginning of the universe, and thus these galaxies are seen soon after they first formed.

“I was happy that we opened a new window into that era,” Miyatake said. “12 billion years ago, things were very different. You see more galaxies that are in the process of formation than at the present; the first galaxy clusters are starting to form as well.” Galaxy clusters comprise 100–1000 galaxies bound by gravity with large amounts of Dark Matter.

Nature: The Laniakea supercluster of galaxies. Milky Way is the red dot. Credit: R. Brent Tully, Hélène Courtois, Yehuda Hoffman & Daniel Pomarède.

“This result gives a very consistent picture of galaxies and their evolution, as well as the Dark Matter in and around galaxies, and how this picture evolves with time,” said Neta Bahcall, Eugene Higgins Professor of Astronomy, professor of astrophysical sciences, and director of undergraduate studies at Princeton University.

One of the most exciting findings of the researchers was related to the clumpiness of Dark Matter. According to the standard theory of cosmology, the ΛCDM model [below], subtle fluctuations in the CMB form pools of densely packed matter by attracting surrounding matter through gravity. This creates inhomogeneous clumps that form stars and galaxies in these dense regions. The group’s findings suggest that their clumpiness measurement was lower than predicted by the ΛCDM model.

Miyatake is enthusiastic about the possibilities. “Our finding is still uncertain,” he said. “But if it is true, it would suggest that the entire model is flawed as you go further back in time. This is exciting because if the result holds after the uncertainties are reduced, it could suggest an improvement of the model that may provide insight into the nature of Dark Matter itself.”

“At this point, we will try to get better data to see if the ΛCDM model is actually able to explain the observations that we have in the universe,” said Andrés Plazas Malagón, associate research scholar at Princeton University. “And the consequence may be that we need to revisit the assumptions that went into this model.”

“One of the strengths of looking at the universe using large-scale surveys, such as the ones used in this research, is that you can study everything that you see in the resulting images, from nearby asteroids in our solar system to the most distant galaxies from the early universe. You can use the same data to explore a lot of new questions,” said Michael Strauss, professor and chair of the Department of Astrophysical Sciences at Princeton University.

This study used data available from existing telescopes, including Planck and Subaru [above].

The European Space Agency [La Agencia Espacial Europea] [Agence spatiale européenne][Europäische Weltraumorganisation](EU) Planck microwave telescope 2009 to 2013.

The group has only reviewed a third of the Subaru Hyper Suprime-Cam Survey data. The next step will be to analyze the entire data set, which should allow for a more precise measurement of the dark matter distribution. In the future, the team expects to use an advanced data set like the Vera C. Rubin Observatory’s Legacy Survey of Space and Time (LSST) to explore more of the earliest parts of space.

The National Science Foundation NOIRLab National Optical Astronomy Observatory Vera C. Rubin Observatory [LSST] Telescope currently under construction on the El Peñón peak at Cerro Pachón Chile, a 2,682-meter-high mountain in Coquimbo Region, in northern Chile, alongside the Gemini South Telescope and Southern Astrophysical Research Telescope.

“LSST will allow us to observe half the sky,” Harikane said. “I don’t see any reason we couldn’t see the Dark Matter distribution 13 billion years ago next.”

__________________________________
Dark Matter Background
Fritz Zwicky discovered Dark Matter in the 1930s when observing the movement of the Coma Cluster., Vera Rubin a Woman in STEM, denied the Nobel, some 30 years later, did most of the work on Dark Matter.

Fritz Zwicky.
Coma cluster via NASA/ESA Hubble, the original example of Dark Matter discovered during observations by Fritz Zwicky and confirmed 30 years later by Vera Rubin.
In modern times, it was astronomer Fritz Zwicky, in the 1930s, who made the first observations of what we now call dark matter. His 1933 observations of the Coma Cluster of galaxies seemed to indicated it has a mass 500 times more than that previously calculated by Edwin Hubble. Furthermore, this extra mass seemed to be completely invisible. Although Zwicky’s observations were initially met with much skepticism, they were later confirmed by other groups of astronomers.

Thirty years later, astronomer Vera Rubin provided a huge piece of evidence for the existence of dark matter. She discovered that the centers of galaxies rotate at the same speed as their extremities, whereas, of course, they should rotate faster. Think of a vinyl LP on a record deck: its center rotates faster than its edge. That’s what logic dictates we should see in galaxies too. But we do not. The only way to explain this is if the whole galaxy is only the center of some much larger structure, as if it is only the label on the LP so to speak, causing the galaxy to have a consistent rotation speed from center to edge.

Vera Rubin, following Zwicky, postulated that the missing structure in galaxies is dark matter. Her ideas were met with much resistance from the astronomical community, but her observations have been confirmed and are seen today as pivotal proof of the existence of dark matter.
Astronomer Vera Rubin at the Lowell Observatory in 1965, worked on Dark Matter (The Carnegie Institution for Science).

Vera Rubin, with Department of Terrestrial Magnetism (DTM) image tube spectrograph attached to the Kitt Peak 84-inch telescope, 1970.

Vera Rubin measuring spectra, worked on Dark Matter(Emilio Segre Visual Archives AIP SPL).
Dark Matter Research

Super Cryogenic Dark Matter Search from DOE’s SLAC National Accelerator Laboratory at Stanford University at SNOLAB (Vale Inco Mine, Sudbury, Canada).

LBNL LZ Dark Matter Experiment xenon detector at Sanford Underground Research Facility Credit: Matt Kapust.

Lamda Cold Dark Matter Accerated Expansion of The universe http scinotions.com the-cosmic-inflation-suggests-the-existence-of-parallel-universes. Credit: Alex Mittelmann.

DAMA at Gran Sasso uses sodium iodide housed in copper to hunt for dark matter LNGS-INFN.

Yale HAYSTAC axion dark matter experiment at Yale’s Wright Lab.

DEAP Dark Matter detector, The DEAP-3600, suspended in the SNOLAB (CA) deep in Sudbury’s Creighton Mine.

The LBNL LZ Dark Matter Experiment Dark Matter project at SURF, Lead, SD.

DAMA-LIBRA Dark Matter experiment at the Italian National Institute for Nuclear Physics’ (INFN’s) Gran Sasso National Laboratories (LNGS) located in the Abruzzo region of central Italy.

DARWIN Dark Matter experiment. A design study for a next-generation, multi-ton dark matter detector in Europe at The University of Zurich [Universität Zürich](CH).

PandaX II Dark Matter experiment at Jin-ping Underground Laboratory (CJPL) in Sichuan, China.

Inside the Axion Dark Matter eXperiment U Washington (US) Credit : Mark Stone U. of Washington. Axion Dark Matter Experiment.

XENONnT experiment at the Laboratori Nazionali del Gran Sasso (LNGS) underground laboratory in Italy.

The University of Western Australia ORGAN Experiment’s main detector. A small copper cylinder called a “resonant cavity” traps photons generated during dark matter conversion. The cylinder is bolted to a “dilution refrigerator” which cools the experiment to very low temperatures.
__________________________________

Science paper:
Physical Review Letters

See the full article here.

five-ways-keep-your-child-safe-school-shootings

Please help promote STEM in your local schools.

Stem Education Coalition

Nagoya University [名古屋大学] (JP), is a Japanese national university located in Chikusa-ku, Nagoya. It is the last Imperial University in Japan, one of the Designated National University and selected as a Top Type university of Top Global University Project by the Japanese government. It is the 3rd highest ranked higher education institution in Japan (72nd worldwide).

The University is the birthplace of the Sakata School of physics and the Hirata School of chemistry. As of 2014, six Nobel Prize winners have been associated with Nagoya University, the third most in Japan and Asia behind Kyoto University [京都大学](JP) and The University of Tokyo [(東京大学](JP).

Nagoya University traces its roots back to 1871 when it was a temporary medical school. In 1939 it became Nagoya Imperial University [名古屋帝国大学]. In 1947 it was renamed Nagoya University [名古屋大学], and became a Japanese national university. In 2014, according to the reform measures of the Ministry of Education, Culture, Sports, Science and Technology, all Japanese national universities became National University Corporation [国立大学法人](JP). The university has a profound tradition of physics and chemistry. Many world-class scientific research achievements include Sakata model, PMNS matrix, Okazaki fragment, Noyori asymmetric hydrogenation, and Blue LED were born in Nagoya University.

In the 20th century, NU’s Kuno Yasu and Katsunuma Seizō were nominated for the Nobel Prize in Physiology or Medicine, Yoshio Ohnuki was nominated for the Nobel Prize in Physics. In the 21st century, NU peoples account for half of the total number of Japanese Nobel Prize winners (up to 2014). Among the six winners of the Nobel Prize in Chemistry and the Physics, there are three professors and five alumni. The number of winners is the third among Japanese universities. In addition, the team under Professor Morishima Kunihiro participated in the Scanpyramids project by using special nuclear emulsion plates. This led to the discovery in 2017 of new chambers in the great pyramid.

In March 2012, Nagoya University played host to the International Symposium on Innovative Nanobiodevices. Three years later, NU was selected as one of the five champion universities for gender equality by the United Nations Entity for Gender Equality and the Empowerment of Women.

In March 2018, Nagoya University was selected as one of top five Designated National University Corporation [指定国立大学法人]. In order to become the largest national higher education corporation in Japan, the Tokai National Higher Education and Research System [国立大学法人東海国立大学機構](JP) established by integrating with Gifu University [岐阜大学](JP) in April 2020, both are major universities in Central Japan.

From “The Conversation (AU)” : “We found some strange radio sources in a distant galaxy cluster. They’re making us rethink what we thought we knew.”

From “The Conversation (AU)”

July 31, 2022

Christopher Riseley
Research Fellow
Università di Bologna (IT)

Tessa Vernstrom
Senior research fellow
The University of Western Australia (AU)

The colliding cluster Abell 3266 as seen across the electromagnetic spectrum, using data from ASKAP and the ATCA (red/orange/yellow colours), XMM-Newton (blue) and the Dark Energy Survey (background map). Christopher Riseley (Università di Bologna), Author provided.

SKA ASKAP Pathfinder Radio Telescope at the Murchison Radio-astronomy Observatory (MRO), on the traditional lands of the Wajarri peoples

ATCA CSIRO Australia Telescope Compact Array (AU), six radio telescopes at the Paul Wild Observatory, is an array of six 22-m antennas located about twenty five kilometres (16 mi) west of the town of Narrabri in Australia.

The European Space Agency [La Agencia Espacial Europea] [Agencia Espacial Europea][Agence spatiale européenne][Europäische Weltraumorganisation](EU) XMM Newton X-ray Telescope.

Dark Energy Camera [DECam] built at DOE’s Fermi National Accelerator Laboratory.

The universe is littered with galaxy clusters – huge structures piled up at the intersections of the cosmic web.

Cosmic web Millenium Simulation MPG Institut für Astrophysik, Garching (DE).

A single cluster can span millions of light-years across and be made up of hundreds, or even thousands, of galaxies.

Nature: The Laniakea supercluster of galaxies. Milky Way is the red dot. Credit: R. Brent Tully, Hélène Courtois, Yehuda Hoffman & Daniel Pomarède.

However, these galaxies represent only a few percent of a cluster’s total mass. About 80% of it is Dark Matter, and the rest is a hot plasma “soup”: gas heated to above 10,000,000℃ and interwoven with weak magnetic fields.

We and our international team of colleagues have identified a series of rarely observed radio objects – a radio relic, a radio halo and fossil radio emission – within a particularly dynamic galaxy cluster called Abell 3266. They defy existing theories about both the origins of such objects and their characteristics.

Relics, haloes and fossils

Galaxy clusters allow us to study a broad range of rich processes – including magnetism and plasma physics – in environments we can’t recreate in our labs.

When clusters collide with each other, huge amounts of energy are put into the particles of the hot plasma, generating radio emission. And this emission comes in a variety of shapes and sizes.

“Radio relics” are one example. They are arc-shaped and sit towards a cluster’s outskirts, powered by shockwaves travelling through the plasma, which cause a jump in density or pressure, and energise the particles. An example of a shockwave on Earth is the sonic boom that happens when an aircraft breaks the sound barrier.

“Radio haloes” are irregular sources that lie towards the cluster’s centre. They’re powered by turbulence in the hot plasma, which gives energy to the particles. We know both haloes and relics are generated by collisions between galaxy clusters – yet many of their gritty details remain elusive.

Then there are “fossil” radio sources. These are the radio leftovers from the death of a supermassive black hole at the centre of a radio galaxy.

When they’re in action, black holes shoot huge jets of plasma far out beyond the galaxy itself. As they run out of fuel and shut off, the jets begin to dissipate. The remnants are what we detect as radio fossils.

Abell 3266

Our new paper, published in the MNRAS [below], presents a highly detailed study of a galaxy cluster called Abell 3266.

This is a particularly dynamic and messy colliding system around 800 million light-years away. It has all the hallmarks of a system that should be host to relics and haloes – yet none had been detected until recently.

Following up on work conducted using the Murchison Widefield Array earlier this year, we used new data from the ASKAP radio telescope and the Australia Telescope Compact Array (ATCA) to see Abell 3266 in more detail.

Our data paint a complex picture. You can see this in the lead image: yellow colours show features where energy input is active. The blue haze represents the hot plasma, captured at X-ray wavelengths.

Redder colours show features that are only visible at lower frequencies. This means these objects are older and have less energy. Either they have lost a lot of energy over time, or they never had much to begin with.

The radio relic is visible in red near the bottom of the image. And our data here reveal particular features that have never been seen before in a relic.

The ‘wrong-way’ relic in Abell 3266 is shown here with yellow/orange/red colours representing the radio brightness. Credit: Christopher Riseley, using data from ASKAP, ATCA, XMM-Newton and the Dark Energy Survey.

Its concave shape is also unusual, earning it the catchy moniker of a “wrong-way” relic. Overall, our data break our understanding of how relics are generated, and we’re still working to decipher the complex physics behind these radio objects.

Ancient remnants of a supermassive black hole

The radio fossil, seen towards the upper right of the lead image (and also below), is very faint and red, indicating it is ancient. We believe this radio emission originally came from the galaxy at the lower left, with a central black hole that has long been switched off.

The radio fossil in Abell 3266 is shown here with red colours and contours depicting the radio brightness measured by ASKAP, and blue colours showing the hot plasma. The cyan arrow points to the galaxy we think once powered the fossil. Credit: Christopher Riseley, using data from ASKAP, XMM-Newton and the Dark Energy Survey.

Our best physical models simply can’t fit the data. This reveals gaps in our understanding of how these sources evolve – gaps that we’re working to fill.

Finally, using a clever algorithm, we de-focused the lead image to look for very faint emission that’s invisible at high resolution, unearthing the first detection of a radio halo in Abell 3266 (see below).

The radio halo in Abell 3266 is shown here with red colours and contours depicting the radio brightness measured by ASKAP, and blue colours showing the hot plasma. The dashed cyan curve marks the outer limits of the radio halo. Credit: Christopher Riseley, using data from ASKAP, XMM-Newton and the Dark Energy Survey.

Towards the future

This is the beginning of the road towards understanding Abell 3266. We have uncovered a wealth of new and detailed information, but our study has raised yet more questions.

The telescopes we used are laying the foundations for revolutionary science from the Square Kilometre Array project.

______________________________________________
The Square Kilometre Array (SKA)– a next-generation telescope due to be completed by the end of the decade – will likely be able to make images of the earliest light in the Universe, but for current telescopes the challenge is to detect the cosmological signal of the stars through the thick hydrogen clouds.

SKA-Square Kilometer Array

SKA Murchison Widefield Array (AU), Boolardy station in outback Western Australia, at the Murchison Radio-astronomy Observatory (MRO), on the traditional lands of the Wajarri peoples.

SKA ASKAP Pathfinder Radio Telescope at the Murchison Radio-astronomy Observatory (MRO), on the traditional lands of the Wajarri peoples

SKA Square Kilometre Array low frequency at Murchison Widefield Array, Boolardy station in outback Western Australia on the traditional lands of the Wajarri peoples

Massachusettes Institute of Technology-Haystack Observatory Westford, Massachusetts. Altitude 131 m (430 ft).

The Massachusetts Institute of Technology Haystack Observatory EDGES telescope in a radio quiet zone at the Murchison Radio-astronomy Observatory in Western Australia, on the traditional lands of the Wajarri peoples.

SKA SARAO Meerkat Telescope (SA), 90 km outside the small Northern Cape town of Carnarvon, SA.

______________________________________________

Studies like ours allow astronomers to figure out what we don’t know – but you can be sure we’re going to find out.

___________________________________________________________________
The Dark Energy Survey

Dark Energy Camera [DECam] built at The DOE’s Fermi National Accelerator Laboratory.

NOIRLab National Optical Astronomy Observatory Cerro Tololo Inter-American Observatory(CL) Victor M Blanco 4m Telescope which houses the Dark-Energy-Camera – DECam at Cerro Tololo, Chile at an altitude of 7200 feet.

NOIRLabNSF NOIRLab NOAO Cerro Tololo Inter-American Observatory(CL) approximately 80 km to the East of La Serena, Chile, at an altitude of 2200 meters.

Timeline of the Inflationary Universe WMAP.

The Dark Energy Survey is an international, collaborative effort to map hundreds of millions of galaxies, detect thousands of supernovae, and find patterns of cosmic structure that will reveal the nature of the mysterious dark energy that is accelerating the expansion of our Universe. The Dark Energy Survey began searching the Southern skies on August 31, 2013.

According to Albert Einstein’s Theory of General Relativity, gravity should lead to a slowing of the cosmic expansion. Yet, in 1998, two teams of astronomers studying distant supernovae made the remarkable discovery that the expansion of the universe is speeding up.
Saul Perlmutter (center) [The Supernova Cosmology Project] shared the 2006 Shaw Prize in Astronomy, the 2011 Nobel Prize in Physics, and the 2015 Breakthrough Prize in Fundamental Physics with Brian P. Schmidt (right) and Adam Riess (left) [The High-z Supernova Search Team] for providing evidence that the expansion of the universe is accelerating.

To explain cosmic acceleration, cosmologists are faced with two possibilities: either 70% of the universe exists in an exotic form, now called Dark Energy, that exhibits a gravitational force opposite to the attractive gravity of ordinary matter, or General Relativity must be replaced by a new theory of gravity on cosmic scales.

The Dark Energy Survey is designed to probe the origin of the accelerating universe and help uncover the nature of Dark Energy by measuring the 14-billion-year history of cosmic expansion with high precision. More than 400 scientists from over 25 institutions in the United States, Spain, the United Kingdom, Brazil, Germany, Switzerland, and Australia are working on the project. The collaboration built and is using an extremely sensitive 570-Megapixel digital camera, DECam, mounted on the Blanco 4-meter telescope at Cerro Tololo Inter-American Observatory, high in the Chilean Andes, to carry out the project.

Over six years (2013-2019), the Dark Energy Survey collaboration used 758 nights of observation to carry out a deep, wide-area survey to record information from 300 million galaxies that are billions of light-years from Earth. The survey imaged 5000 square degrees of the southern sky in five optical filters to obtain detailed information about each galaxy. A fraction of the survey time is used to observe smaller patches of sky roughly once a week to discover and study thousands of supernovae and other astrophysical transients.
___________________________________________________________________

Dark Matter Background
Fritz Zwicky discovered Dark Matter in the 1930s when observing the movement of the Coma Cluster., Vera Rubin a Woman in STEM, denied the Nobel, some 30 years later, did most of the work on Dark Matter.

Fritz Zwicky.
Coma cluster via NASA/ESA Hubble, the original example of Dark Matter discovered during observations by Fritz Zwicky and confirmed 30 years later by Vera Rubin.
In modern times, it was astronomer Fritz Zwicky, in the 1930s, who made the first observations of what we now call dark matter. His 1933 observations of the Coma Cluster of galaxies seemed to indicated it has a mass 500 times more than that previously calculated by Edwin Hubble. Furthermore, this extra mass seemed to be completely invisible. Although Zwicky’s observations were initially met with much skepticism, they were later confirmed by other groups of astronomers.

Thirty years later, astronomer Vera Rubin provided a huge piece of evidence for the existence of dark matter. She discovered that the centers of galaxies rotate at the same speed as their extremities, whereas, of course, they should rotate faster. Think of a vinyl LP on a record deck: its center rotates faster than its edge. That’s what logic dictates we should see in galaxies too. But we do not. The only way to explain this is if the whole galaxy is only the center of some much larger structure, as if it is only the label on the LP so to speak, causing the galaxy to have a consistent rotation speed from center to edge.

Vera Rubin, following Zwicky, postulated that the missing structure in galaxies is dark matter. Her ideas were met with much resistance from the astronomical community, but her observations have been confirmed and are seen today as pivotal proof of the existence of dark matter.
Astronomer Vera Rubin at the Lowell Observatory in 1965, worked on Dark Matter (The Carnegie Institution for Science).

Vera Rubin, with Department of Terrestrial Magnetism (DTM) image tube spectrograph attached to the Kitt Peak 84-inch telescope, 1970.

Vera Rubin measuring spectra, worked on Dark Matter(Emilio Segre Visual Archives AIP SPL).
Dark Matter Research

Super Cryogenic Dark Matter Search from DOE’s SLAC National Accelerator Laboratory at Stanford University at SNOLAB (Vale Inco Mine, Sudbury, Canada).

LBNL LZ Dark Matter Experiment xenon detector at Sanford Underground Research Facility Credit: Matt Kapust.

Lamda Cold Dark Matter Accerated Expansion of The universe http scinotions.com the-cosmic-inflation-suggests-the-existence-of-parallel-universes. Credit: Alex Mittelmann.

DAMA at Gran Sasso uses sodium iodide housed in copper to hunt for dark matter LNGS-INFN.

Yale HAYSTAC axion dark matter experiment at Yale’s Wright Lab.

DEAP Dark Matter detector, The DEAP-3600, suspended in the SNOLAB (CA) deep in Sudbury’s Creighton Mine.

The LBNL LZ Dark Matter Experiment Dark Matter project at SURF, Lead, SD.

DAMA-LIBRA Dark Matter experiment at the Italian National Institute for Nuclear Physics’ (INFN’s) Gran Sasso National Laboratories (LNGS) located in the Abruzzo region of central Italy.

DARWIN Dark Matter experiment. A design study for a next-generation, multi-ton dark matter detector in Europe at The University of Zurich [Universität Zürich](CH).

PandaX II Dark Matter experiment at Jin-ping Underground Laboratory (CJPL) in Sichuan, China.

Inside the Axion Dark Matter eXperiment U Washington (US) Credit : Mark Stone U. of Washington. Axion Dark Matter Experiment.

XENONnT experiment at the Laboratori Nazionali del Gran Sasso (LNGS) underground laboratory in Italy.

The University of Western Australia ORGAN Experiment’s main detector. A small copper cylinder called a “resonant cavity” traps photons generated during dark matter conversion. The cylinder is bolted to a “dilution refrigerator” which cools the experiment to very low temperatures.
__________________________________

Science paper:
MNRAS

See the full article here .

five-ways-keep-your-child-safe-school-shootings

Please help promote STEM in your local schools.

Stem Education Coalition

The Conversation (AU) launched as a pilot project in October 2014. It is an independent source of news and views from the academic and research community, delivered direct to the public.
Our team of professional editors work with university and research institute experts to unlock their knowledge for use by the wider public.

Access to independent, high quality, authenticated, explanatory journalism underpins a functioning democracy. Our aim is to promote better understanding of current affairs and complex issues. And hopefully allow for a better quality of public discourse and conversation.

From INFN -National Laboratory of Frascati [Laboratori Nazionali di Frascati] (IT) : “First results from a Search for New Physics in Electronic Recoils from XENONnT”

From INFN -National Laboratory of Frascati [Laboratori Nazionali di Frascati] (IT)

XENONnT, the latest detector of the XENON Dark Matter program, shows an unprecedentedly low background which facilitates searches for new, very rare phenomena with high sensitivity. First results clarify an exciting excess observed in the predecessor XENON1T and set strong limits on new physics scenarios.

The XENONnT experiment was designed to look for elusive Dark Matter particles. The detector holds almost 6000 kg of ultrapure liquid xenon as a target for particle interactions; it is installed inside a water Čerenkov active muon and neutron veto, deep underground at the INFN Laboratori Nazionali del Gran Sasso in Italy. Despite the challenging pandemic situation, XENONnT was constructed and subsequently commissioned between spring 2020 and spring 2021. XENONnT took the first science data over 97.1 days, from July 6 to November 10, 2021.

Experiments of this type require the lowest possible levels of natural radioactivity of any kind, both from sources intrinsically present in the liquid xenon target and from construction materials and the environment. The former, dominated by radon, is the most difficult to reduce and its elimination represents the holy grail of current searches at the sensitivity level of XENONnT. However, the XENON collaboration has been instrumental in reducing radon to an unprecedentedly low-level, thanks to extensive material screening and the successful operation of an online cryogenic distillation column that actively removes radon from the xenon.

Two years ago, the XENON collaboration announced the observation of an excess of electronic recoil events in the XENON1T experiment. The result triggered a lot of interest and many publications since this could be interpreted as a signal of new physics beyond known phenomena. Interactions with electrons in the atomic shell within the liquid xenon from solar axions, neutrinos with an anomalous magnetic moment, axion-like particles, or hypothetical dark sector particles might induce so-called “electronic recoil” signals. Today the XENON collaboration has released the first results from its new and more sensitive experiment, XENONnT, with one-fifth of the electronic recoil background of its predecessor, XENON1T. The absence of an excess in the new data indicates that the origin of the XENON1T signal was trace amounts of tritium in the liquid xenon, one of the hypotheses considered at the time. In consequence, this leads now to very strong limits on new physics scenarios originally invoked to explain an excess.

With this new result, obtained through a blind analysis, XENONnT makes its debut, with an initial exposure slightly larger than 1 tonne x year. The existing data are being further analyzed to search for weakly interacting massive particles (WIMPs), one of the most promising candidates of Dark Matter in the Universe. XENONnT is meanwhile collecting more data, aiming for even better sensitivity as part of its science program for the next years.

XENONnT experiment at the Laboratori Nazionali del Gran Sasso (LNGS) underground laboratory in Italy.

__________________________________
Dark Matter Background
Fritz Zwicky discovered Dark Matter in the 1930s when observing the movement of the Coma Cluster., Vera Rubin a Woman in STEM, denied the Nobel, some 30 years later, did most of the work on Dark Matter.

Fritz Zwicky.
Coma cluster via NASA/ESA Hubble, the original example of Dark Matter discovered during observations by Fritz Zwicky and confirmed 30 years later by Vera Rubin.
In modern times, it was astronomer Fritz Zwicky, in the 1930s, who made the first observations of what we now call dark matter. His 1933 observations of the Coma Cluster of galaxies seemed to indicated it has a mass 500 times more than that previously calculated by Edwin Hubble. Furthermore, this extra mass seemed to be completely invisible. Although Zwicky’s observations were initially met with much skepticism, they were later confirmed by other groups of astronomers.

Thirty years later, astronomer Vera Rubin provided a huge piece of evidence for the existence of dark matter. She discovered that the centers of galaxies rotate at the same speed as their extremities, whereas, of course, they should rotate faster. Think of a vinyl LP on a record deck: its center rotates faster than its edge. That’s what logic dictates we should see in galaxies too. But we do not. The only way to explain this is if the whole galaxy is only the center of some much larger structure, as if it is only the label on the LP so to speak, causing the galaxy to have a consistent rotation speed from center to edge.

Vera Rubin, following Zwicky, postulated that the missing structure in galaxies is dark matter. Her ideas were met with much resistance from the astronomical community, but her observations have been confirmed and are seen today as pivotal proof of the existence of dark matter.
Astronomer Vera Rubin at the Lowell Observatory in 1965, worked on Dark Matter (The Carnegie Institution for Science).

Vera Rubin, with Department of Terrestrial Magnetism (DTM) image tube spectrograph attached to the Kitt Peak 84-inch telescope, 1970.

Vera Rubin measuring spectra, worked on Dark Matter(Emilio Segre Visual Archives AIP SPL).
Dark Matter Research

Super Cryogenic Dark Matter Search from DOE’s SLAC National Accelerator Laboratory at Stanford University at SNOLAB (Vale Inco Mine, Sudbury, Canada).

LBNL LZ Dark Matter Experiment xenon detector at Sanford Underground Research Facility Credit: Matt Kapust.

Lamda Cold Dark Matter Accerated Expansion of The universe http scinotions.com the-cosmic-inflation-suggests-the-existence-of-parallel-universes. Credit: Alex Mittelmann.

DAMA at Gran Sasso uses sodium iodide housed in copper to hunt for dark matter LNGS-INFN.

Yale HAYSTAC axion dark matter experiment at Yale’s Wright Lab.

DEAP Dark Matter detector, The DEAP-3600, suspended in the SNOLAB (CA) deep in Sudbury’s Creighton Mine.

The LBNL LZ Dark Matter Experiment Dark Matter project at SURF, Lead, SD.

DAMA-LIBRA Dark Matter experiment at the Italian National Institute for Nuclear Physics’ (INFN’s) Gran Sasso National Laboratories (LNGS) located in the Abruzzo region of central Italy.

DARWIN Dark Matter experiment. A design study for a next-generation, multi-ton dark matter detector in Europe at The University of Zurich [Universität Zürich](CH).

PandaX II Dark Matter experiment at Jin-ping Underground Laboratory (CJPL) in Sichuan, China.

Inside the Axion Dark Matter eXperiment U Washington (US) Credit : Mark Stone U. of Washington. Axion Dark Matter Experiment.

__________________________________

See the full article here .

five-ways-keep-your-child-safe-school-shootings

Please help promote STEM in your local schools.

Stem Education Coalition

Gran Sasso LABORATORI NAZIONALI del GRAN SASSO, located in the Abruzzo region of central Italy

INFN Gran Sasso (IT) is the largest underground laboratory in the world devoted to neutrino and astroparticle physics, a worldwide research facility for scientists working in this field of research, where particle physics, cosmology and astrophysics meet. It is unequalled anywhere else, as it offers the most advanced underground infrastructures in terms of dimensions, complexity and completeness.

LNGS is funded by the National Institute for Nuclear Physics (INFN), the Italian Institution in charge to coordinate and support research in elementary particles physics, nuclear and sub nuclear physics

Located between L’Aquila and Teramo, at about 120 kilometres from Rome, the underground structures are on one side of the 10-kilometre long highway tunnel which crosses the Gran Sasso massif (towards Rome); the underground complex consists of three huge experimental halls (each 100-metre long, 20-metre large and 18-metre high) and bypass tunnels, for a total volume of about 180.000 m^3.

Access to experimental halls is horizontal and it is made easier by the highway tunnel. Halls are equipped with all technical and safety equipment and plants necessary for the experimental activities and to ensure proper working conditions for people involved.

The 1400 metre-rock thickness above the Laboratory represents a natural coverage that provides a cosmic ray flux reduction by one million times; moreover, the flux of neutrons in the underground halls is about thousand times less than on the surface due to the very small amount of uranium and thorium of the Dolomite calcareous rock of the mountain.

The permeability of cosmic radiation provided by the rock coverage together with the huge dimensions and the impressive basic infrastructure, make the Laboratory unmatched in the detection of weak or rare signals, which are relevant for astroparticle, sub nuclear and nuclear physics.

Outside, immersed in a National Park of exceptional environmental and naturalistic interest on the slopes of the Gran Sasso mountain chain, an area of more than 23 acres hosts laboratories and workshops, the Computing Centre, the Directorate and several other Offices.

Currently 1100 scientists from 29 different Countries are taking part in the experimental activities of LNGS.
LNGS research activities range from neutrino physics to dark matter search, to nuclear astrophysics, and also to earth physics, biology and fundamental physics.

From “Science Magazine” : “A quantum sense for dark matter”

From “Science Magazine”

28 Apr 2022
Adrian Cho

Bullet Cluster NASA Chandra NASA ESA Hubble, evidence of shock.

A collision of galaxy clusters separated gas (pink) from dark matter (blue), mapped from subtle gravitational distortions in the images of background galaxies. Credits:(X-ray) NASA/CXC/CFA/M. Markevitch et al.; (Optical) D. Clowe et al. NASA/STSCI; Magellan/U. Arizona/; (Lensing Map) D. Clowe et al./NASA/STSCI; ESO WFI; Magellan/U. Arizona/

The National Aeronautics and Space Administration Chandra X-ray telescope.

National Aeronautics and Space Administration/The European Space Agency [La Agencia Espacial Europea] [Agence spatiale européenne][Europäische Weltraumorganisation](EU) Hubble Space Telescope.

Wide Field Imager on the 2.2 meter MPG/ESO telescope at Cerro LaSilla (CL)

MPG Institute for Astronomy [Max-Planck-Institut für Astronomie](DE)European Southern Observatory(EU)2.2 meter telescope at Cerro La Silla, Chile, 600 km north of Santiago de Chile at an altitude of 2400 metres.

Carnegie 6.5 meter Magellan Baade and Clay Telescopes located at Carnegie’s Las Campanas Observatory, Chile. over 2,500 m (8,200 ft) high.

Carnegie Institution for Science’s Las Campanas Observatory on Cerro Pachón in the southern Atacama Desert of Chile in the Atacama Region approximately 100 kilometres (62 mi) northeast of the city of La Serena,near the southern end and over 2,500 m (8,200 ft) high.

Kent Irwin has a vision: He aims to build a glorified radio that will reveal the nature of Dark Matter, the invisible stuff that makes up 85% of all matter. For decades, physicists have struggled to figure out what the stuff is, stalking one hypothetical particle after another, only to come up empty. However, if Dark Matter consists of certain nearly massless particles, then in the right setting it might generate faint, unquenchable radio waves. Irwin, a quantum physicist at Stanford University, plans to tune in to that signal in an experiment called Dark Matter Radio (DM Radio).

No ordinary radio will do. To make the experiment practical, Irwin’s team plans to transform it into a quantum sensor—one that exploits the strange rules of quantum mechanics. Quantum sensors are a hot topic, having received $1.275 billion in funding in the 2018 U.S. National Quantum Initiative. Some scientists are employing them as microscopes and gravimeters. But because of the devices’ unparalleled sensitivity, Irwin says, “dark matter is a killer app for quantum sensing.”

DM Radio is just one of many new efforts to use quantum sensors to hunt the stuff. Some approaches detect the granularity of the subatomic realm, in which matter and energy come in tiny packets called quanta. Others exploit the trade-offs implicit in the famous Heisenberg uncertainty principle. Still others borrow technologies being developed for quantum computing. Physicists don’t agree on the definition of a quantum sensor, and none of the concepts is entirely new. “I would argue that quantum sensing has been happening in one form or another for a century,” says Peter Abbamonte, a condensed matter physicist and leader of the Center on Quantum Sensing and Quantum Materials at the University of Illinois – Urbana-Champaign (UIUC).

Still, Yonatan Kahn, a theoretical physicist at UIUC, says quantum sensors open the way to testing new ideas for what Dark Matter might be. “You shouldn’t just go blindly looking” for Dark Matter, Kahn says. “But even if your model is made of bubblegum and paperclips, if it satisfies all cosmological constraints, it’s fair game.” Quantum sensing is essential for testing many of those models, Irwin says. “It can make it possible to do an experiment in 3 years that would otherwise take thousands of years.”

Astrophysical evidence for Dark Matter has accreted for decades. For example, the stars in spiral galaxies appear to whirl so fast that their own gravity shouldn’t keep them from flying into space. The observation implies that the stars circulate within a vast cloud of Dark Matter that provides the additional gravity needed to rein them in. Physicists assume it consists of swarms of some as-yet-unknown fundamental particle.

In the 1980s theorists hypothesized what soon became the leading contender: weakly interacting massive particles (WIMPs). Emerging in the hot soup of particles after the big bang, WIMPs would interact with ordinary matter only through gravity and the weak nuclear force, which produces a kind of radioactive decay. Like the particles that convey the weak force, the W and Z bosons, WIMPs would weigh roughly 100 times as much as a proton. And just enough WIMPs would naturally linger—a few thousand per cubic meter near Earth—to account for Dark Matter.

Occasionally a WIMP should crash into an atomic nucleus and blast it out of its atom. So, to spot WIMPs, experimenters need only look for recoiling nuclei in detectors built deep underground to protect them from extraneous radiation. But no signs of WIMPs have appeared, even as detectors have grown bigger and more sensitive. Fifteen years ago, WIMP detectors weighed kilograms; now, the biggest contain several tons of frigid liquid xenon.

The second most popular candidate—and one DM Radio targets—is the axion. Far lighter than WIMPs, axions are predicted by a theory that explains a certain symmetry of the strong nuclear force, which binds quarks into trios to make protons and neutrons. Axions would also emerge in the early universe, and theorists originally estimated they could account for Dark Matter if the axion has a mass between one-quadrillionth and 100-quadrillionths of a proton.

In a strong magnetic field an axion should sometimes turn into a radio photon whose frequency depends on the axion’s mass. To amplify the faint signal, physicists place in the field an ultracold cylindrical metal cavity designed to resonate with radio waves just as an organ pipe rings with sound. The Axion Dark Matter Experiment (ADMX) at the University of Washington, Seattle, scans the low end of the mass range, and an experiment called the Haloscope at Yale Sensitive to Axion CDM (HAYSTAC) at Yale University probes the high end. But no axions have shown up yet.

Inside the Axion Dark Matter eXperiment U Washington Credit : Mark Stone U. of Washington. Axion Dark Matter Experiment.

Yale HAYSTAC axion dark matter experiment at Yale’s Wright Lab.

The Massachusetts Institute of Technology Haystack Observatory EDGES telescope in a radio quiet zone at the Murchison Radio-astronomy Observatory in Western Australia, on the traditional lands of the Wajarri peoples.

In recent years physicists have begun to consider other possibilities. Maybe axions are either more or less massive than previously estimated. Instead of one type of particle Dark Matter might even consist of a hidden “dark sector” of multiple new particles that would interact through gravity but not the three other forces, electromagnetism and the weak and strong nuclear forces. Rather, they would have their own forces, says Kathryn Zurek, a theorist at the California Institute of Technology. So, just as photons convey the electromagnetic force dark photons might convey a dark electromagnetic force. Dark and ordinary electromagnetism might intertwine so that rarely, a dark photon could morph into an ordinary one.

To spot such quarry Dark Matter hunters have turned to quantum sensors—a shift partly inspired by another hot field: quantum computing. A quantum computer flips quantum bits, or qubits, that can be set to 0, 1, or, thanks to the odd rules of quantum mechanics, 0 and 1 at the same time. That may seem irrelevant to hunting dark matter, but such qubits must be carefully controlled and shielded from external interference, exactly what Dark Matter hunters already do with their detectors, says Aaron Chou, a physicist at Fermi National Accelerator Laboratory (Fermilab) who works on ADMX. “We have to keep these devices very, very well isolated from the environment so that when we see the very, very rare event, we’re more confident that it might be due to the Dark Matter.”

The interest in quantum sensors also reflects the tinkerer culture of Dark Matter hunters, says Reina Maruyama, a nuclear and particle physicist at Yale and co-leader of HAYSTAC. The field has long attracted people interested in developing new detectors and in quick, small-scale experiments, she says. “This kind of footloose approach has always been possible in the Dark Matter field.”

For some novel searches, the simplest definition of a quantum sensor may do: It’s any device capable of detecting a single quantum particle, such as a photon or an energetic electron. “I call a quantum sensor something that can detect single quanta in whatever form that takes,” Zurek says. That’s what is needed for hunting particles slightly lighter than WIMPs and plumbing the dark sector, she says.

Such runty particles wouldn’t produce detectable nuclear recoils. A wispy dark sector particle could interact with ordinary matter by emitting a dark photon that morphs into an ordinary photon. But that low-energy photon would barely nudge a nucleus.

In the right semiconductor, however, the same photon could excite an electron and enable it to flow through the material. Kahn and Abbamonte are working on an extremely sensitive photodiode, a device that produces an electrical signal when it absorbs light. Were such a device shielded from light and other forms of radiation and cooled to near absolute zero to reduce noise, a Dark Matter signal would stand out as a steady pitter-pat of tiny electrical pulses.

A chip that could sense dark photons (first image) and an axion detector, HAYSTAC, could fit on a tabletop despite their high sensitivity. (First image) Roger Romani/University of California, Berkeley; (Second image) Karl Van Bibber.

The trick is to find a semiconductor sensitive to very low-energy photons, Kahn says. The industrial standard, silicon, releases an electron when it absorbs a photon with an energy of at least 1.1 electron volts (eV). To detect dark sector particles with masses as low as 1/100,000th that of a proton, the material would need to unleash an electron when pinged by a photon of just 0.03 eV. So Kahn, Abbamonte, and colleagues at The DOE’s Los Alamos National Laboratory are exploring “narrow bandgap” semiconductors such as a compound of europium, indium, and antimony.

Even lighter dark-sector particles would create photons with too little energy to liberate an electron in the most sensitive semiconductor. To hunt for them, Zurek and Matt Pyle, a detector physicist at the University of California, Berkeley, are developing a detector that would sense the infinitesimal quantized vibrations set off when a dark photon creates an ordinary photon that pings a nucleus. It would “only rattle that nucleus and produce a bunch of vibrations,” Pyle says. “So the detectors must be fundamentally different.”

Their detector consists of a single crystal of material composed of two types of ions with opposite charges, such as gallium arsenide. The feeble photon spawned by a dark photon would nudge the different ions in opposite directions, setting off quantized vibrations called optical phonons. To detect these vibrations, Zurek and Pyle dot the crystal with small patches of tungsten and chill it to temperatures near absolute zero, where tungsten becomes a superconductor that carries electricity without resistance. Any phonons would slightly warm the tungsten, reducing its superconductivity and leading to a noticeable spike in its resistance.

Within 5 years, the researchers hope to improve their detector’s sensitivity by a factor of 10 so that they can sense a single phonon and hunt dark-sector particles weighing one-millionth as much as a proton. To provide the Dark Matter, such particles would have to be so numerous that a detector weighing just a few kilograms should be able to spot them or rule them out. And because so few experiments have probed this mass range, even little prototype detectors unshielded from background radiation can yield interesting data, Pyle says. “We run just in our lab above ground, and we can get world-leading results.”

Some physicists argue that true quantum sensors should do something more subtle. The Heisenberg uncertainty principle states that if you simultaneously measure the position and momentum of an electron, the product of the uncertainties in those measurements must exceed a “standard quantum limit.” That means no measurement can yield a perfectly precise result, no matter how it’s done. However, the principle also implies you can swap greater uncertainty in one measurement for greater precision in the other. To some physicists, a quantum sensor is one that exploits that trade-off.

Physicists are using such schemes to enhance axion searches. To make up Dark Matter, those lightweight particles would be so numerous that en masse they’d act like a wave, just as sunlight acts more like a light wave than a hail of photons. So with their metal cavities, ADMX and HAYSTAC researchers are searching for the conversion of an invisible axion wave into a detectable radio wave.

Like any wave, the radio wave will have an amplitude that reveals how strong it is and a phase that marks its exact synchronization relative to whatever ultraprecise clock you might choose. Conventional radio circuits measure both and run into a limit set by the uncertainty principle. But axion hunters care only about the signal’s amplitude—is a wave there or not?—and quantum mechanics lets them measure it with greater precision in exchange for more uncertainty in the phase.

HAYSTAC experimenters exploit that trade-off to tamp down noise in their experiment. The vacuum—the backdrop for the measurement—can itself be considered a wave. Although that vacuum wave has on average zero amplitude, its amplitude is still uncertain and fluctuates to create noise. In HAYSTAC a special amplifier reduces the vacuum’s amplitude fluctuations while allowing those in the irrelevant phase to grow bigger, causing any axion signal to stand out more readily. Last year, HAYSTAC researchers reported in Nature that they had searched for and ruled out axions in a narrow range around 19-quadrillionths of a proton mass. By squeezing the noise, they increased the speed of the search by a factor of 2, Maruyama says, and validated the principle.

Such “squeezing” has been demonstrated for decades in laboratory experiments with lasers and optics. Now, Irwin says, “These techniques for beating the standard quantum limit [have] been used to actually do something better, as opposed to do something in a demonstration.” In the DM Radio experiment, he hopes to use a related technique to probe for even lighter axions as well as dark photons.

Instead of a resonating cavity, DM Radio consists of a radio circuit containing a charge-storing capacitor and a current-storing inductor—a carefully designed coil of wire—both placed in a magnetic field. Axions could convert to radio waves within the inductor coil to create a resonating signal in the circuit at a certain frequency. Researchers can also look for dark photons by reconfiguring the coil and turning off the magnetic field.

To read out the signal, Irwin’s scheme plays on another implication of quantum mechanics, that by measuring a system’s state you may change it. The researchers couple their resonating circuit to a second, higher frequency circuit, so that, much as in AM radio, any Dark Matter signal would make the amplitude of the higher frequency carrier wave warble. The stronger the coupling, the bigger the warbling, and the more prominent the signal. But stronger coupling also injects noise that could stymie efforts to measure Dark Matter with greater precision.

Again, a quantum trade-off comes to the rescue. The researchers modify their carrier wave by injecting a tiny warble at the frequency they hope to probe. Just by random chance, that input warble and any Dark Matter signal will likely be somewhat out of sync, or phase. But the Dark Matter wave can be thought of as the sum of two components: one that’s exactly in sync with the added signal and one that’s exactly out of sync with it—much as any direction on a map is a combination of north-south and east-west. The experiment is designed to measure the in-sync component with greater precision while injecting all the disturbance into the out-of-sync component, making the measurement more sensitive and accelerating the rate at which the experiment can scan different frequencies.

Irwin and colleagues have already run a small prototype of the experiment. They are now building a larger version, and ultimately they plan one with a coil that has a volume of 1 cubic meter. Implementing the quantum sensing is essential, Irwin says, as without it, scanning the entire frequency range would take thousands of years.

Some Dark Matter hunters are explicitly borrowing hardware from quantum computing. For example, Fermilab’s Chou and colleagues have used a superconducting qubit—the same kind Google and IBM use in their quantum computers—to perform a proof-of-principle search for dark photons in a very narrow energy range. Like a smaller version of ADMX or HAYSTAC, their experiment centers on a resonating cavity, this one drilled into the edge of an aluminum plate. There a dark photon could convert into radio waves, although at a higher frequency than in ADMX or HAYSTAC. Ordinarily, experimenters would bleed the radio waves out through a hole in the cavity and measure them with a low-noise amplifier. However, the tiny cavity would generate a signal so faint it would drown in noise from the amplifier itself.

The qubit sidesteps that problem. Like any other qubit, the tiny superconducting circuit can act like a clock, cycling between different combinations of 0 and 1 at a rate that depends on the difference in energy between the circuit’s 0 and 1 states. That difference in turn depends on whether there are any radio photons in the cavity. Even one is enough to speed up the clock, Chou says. “We’re going to stick this artificial atomic clock in the cavity and see if it still keeps good time.”

The measurement probes only the amplitude of the radio waves and not their phase, obtaining greater precision in the former in exchange for greater uncertainty in the latter, the team reported last year in Physical Review Letters. It might speed up dark photon searches by as much as a factor of 1300, Chou says, and it could be extended to search for axions, if researchers could apply a magnetic field to the cavity while shielding the sensitive qubit.

One group has invented a scheme to search for WIMPs using another candidate qubit: a so-called nitrogen vacancy (NV) center within a diamond crystal. In an NV, a nitrogen atom replaces a carbon atom in the crystal lattice and creates an adjacent, empty site that collects a pair of electrons that can serve as qubit. A WIMP passing through a diamond can bump carbon atoms out of the way, leaving a trail of NVs roughly 100 nanometers long, says Ronald Walsworth, an experimental physicist at the University of Maryland, College Park. The NVs will absorb and emit light of specific wavelengths, so the track can be spotted clearly with fluorescence microscopy.

That scheme has little to do with quantum computing, but it would address a looming problem for WIMP searches. If current liquid xenon detectors get much bigger, they should start to see well-known particles called neutrinos, which stream from the Sun. To tell a WIMP from a neutrino, physicists would need to know where a particle came from, as WIMPs should come from the plane of the Galaxy rather than the Sun. A liquid xenon detector can’t determine the direction of a particle that caused a signal. A detector made of diamonds could.

Walsworth envisions a detector formed of millions of millimeter-size synthetic diamonds. A diamond would flash when pierced by a neutrino or WIMP, and an automated system would remove it and scan it for an NV track, using the time of the flash to determine the track’s orientation relative to the Sun and the Galaxy, the team explained last year in Quantum Science and Technology. Walsworth hopes to build a prototype detector in a few years. “I absolutely do not want to claim that our idea would work or that it’s better than other approaches,” he says. “But I think it’s promising enough to go forward.”

Physicists have proposed many other ideas for using quantum sensors to search for Dark Matter, and the influx of money should help transform them into new technologies, Zurek says. “Things can move faster when you’re funded,” she says. As tool builders, Dark Matter hunters embrace that push. “They have a great hammer, so they started looking for nails,” Walsworth says. Perhaps they’ll bang out a discovery of cosmic proportions.

__________________________________
Dark Matter Background
Fritz Zwicky discovered Dark Matter in the 1930s when observing the movement of the Coma Cluster., Vera Rubin a Woman in STEM, denied the Nobel, some 30 years later, did most of the work on Dark Matter.

Fritz Zwicky.
Coma cluster via NASA/ESA Hubble, the original example of Dark Matter discovered during observations by Fritz Zwicky and confirmed 30 years later by Vera Rubin.
In modern times, it was astronomer Fritz Zwicky, in the 1930s, who made the first observations of what we now call dark matter. His 1933 observations of the Coma Cluster of galaxies seemed to indicated it has a mass 500 times more than that previously calculated by Edwin Hubble. Furthermore, this extra mass seemed to be completely invisible. Although Zwicky’s observations were initially met with much skepticism, they were later confirmed by other groups of astronomers.

Thirty years later, astronomer Vera Rubin provided a huge piece of evidence for the existence of dark matter. She discovered that the centers of galaxies rotate at the same speed as their extremities, whereas, of course, they should rotate faster. Think of a vinyl LP on a record deck: its center rotates faster than its edge. That’s what logic dictates we should see in galaxies too. But we do not. The only way to explain this is if the whole galaxy is only the center of some much larger structure, as if it is only the label on the LP so to speak, causing the galaxy to have a consistent rotation speed from center to edge.

Vera Rubin, following Zwicky, postulated that the missing structure in galaxies is dark matter. Her ideas were met with much resistance from the astronomical community, but her observations have been confirmed and are seen today as pivotal proof of the existence of dark matter.
Astronomer Vera Rubin at the Lowell Observatory in 1965, worked on Dark Matter (The Carnegie Institution for Science).

Vera Rubin, with Department of Terrestrial Magnetism (DTM) image tube spectrograph attached to the Kitt Peak 84-inch telescope, 1970.

Vera Rubin measuring spectra, worked on Dark Matter(Emilio Segre Visual Archives AIP SPL).
Dark Matter Research

Super Cryogenic Dark Matter Search from DOE’s SLAC National Accelerator Laboratory at Stanford University at SNOLAB (Vale Inco Mine, Sudbury, Canada).

LBNL LZ Dark Matter Experiment xenon detector at Sanford Underground Research Facility Credit: Matt Kapust.

Lamda Cold Dark Matter Accerated Expansion of The universe http scinotions.com the-cosmic-inflation-suggests-the-existence-of-parallel-universes. Credit: Alex Mittelmann.

DAMA at Gran Sasso uses sodium iodide housed in copper to hunt for dark matter LNGS-INFN.

Yale HAYSTAC axion dark matter experiment at Yale’s Wright Lab.

DEAP Dark Matter detector, The DEAP-3600, suspended in the SNOLAB (CA) deep in Sudbury’s Creighton Mine.

The LBNL LZ Dark Matter Experiment Dark Matter project at SURF, Lead, SD.

DAMA-LIBRA Dark Matter experiment at the Italian National Institute for Nuclear Physics’ (INFN’s) Gran Sasso National Laboratories (LNGS) located in the Abruzzo region of central Italy.

DARWIN Dark Matter experiment. A design study for a next-generation, multi-ton dark matter detector in Europe at The University of Zurich [Universität Zürich](CH).

PandaX II Dark Matter experiment at Jin-ping Underground Laboratory (CJPL) in Sichuan, China.

Inside the Axion Dark Matter eXperiment U Washington (US) Credit : Mark Stone U. of Washington. Axion Dark Matter Experiment.
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