Tagged: Dark Energy Toggle Comment Threads | Keyboard Shortcuts

  • richardmitnick 4:25 pm on May 3, 2021 Permalink | Reply
    Tags: "Search for 'dark energy' could illuminate origin and evolution and fate of universe", , , , , Dark Energy, HETDEX-the Hobby-Eberly Telescope Dark Energy Experiment., Hobby-Eberly 9.1 meter Telescope,   

    From Pennsylvania State University: “Search for ‘dark energy’ could illuminate origin and evolution and fate of universe” 

    Penn State Bloc

    From Pennsylvania State University

    May 03, 2021
    Seth Palmer

    The universe we see is only the very tip of the vast cosmic iceberg.

    The hundreds of billions of galaxies it contains, each of them home to billions of stars, planets and moons as well as massive star-and-planet-forming clouds of gas and dust, and all of the visible light and other energy we can detect in the form of electromagnetic radiation, such as radio waves, gamma rays and X-rays — in short, everything we’ve ever seen with our telescopes — only amounts to about 5% of all the mass and energy in the universe.

    Along with this so-called normal matter there is also dark matter, which can’t be seen, but can be observed by its gravitational effect on normal, visible matter, and makes up another 27% of the universe. Add them together, and they only total 32% of the mass of the universe — so where’s the other 68%?

    Dark Energy.

    Dark Energy Survey

    The Dark Energy Survey (DES) 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. DES began searching the Southern skies on August 31, 2013.

    According to 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. 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.

    DES 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 DES 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.

    1
    This pie chart shows rounded values for the three known components of the universe: normal matter, dark matter, and dark energy. IMAGE: NASA’s Goddard Space Flight Center (US)

    So what exactly is dark energy? Put simply, it’s a mysterious force that’s pushing the universe outward and causing it to expand faster as it ages, engaged in a cosmic tug-of-war with dark matter, which is trying to pull the universe together. Beyond that, we don’t yet understand what dark energy is, but Penn State astronomers are at the core of a group that’s aiming to find out through a unique and ambitious project 16 years in the making: HETDEX, the Hobby-Eberly Telescope Dark Energy Experiment.

    HETDEX is a collaboration of The University of Texas at Austin (US), Pennsylvania State University (US), Texas A&M University (US), Universities-Sternwärte Munich [Universitäts-Sternwarte München] (DE), Leibniz Institute for Astrophysics [Leibniz-Institut für Astrophysik] (DE) (AIP), Max-Planck-Institut für Extraterrestrische Physik, Institut für Astrophysik Göttingen, and University of Oxford (UK). Financial support is provided by the State of Texas, the United States Air Force, the National Science Foundation and the generous contributions of many private foundations and individuals.

    “HETDEX has the potential to change the game,” said Associate Professor of Astronomy and Astrophysics Donghui Jeong.

    Dark energy and the expanding universe

    Today there is consensus among astronomers that the universe we inhabit is expanding, and that its expansion is accelerating, but the idea of an expanding universe is less than a century old, and the notion of dark energy (or anything else) accelerating that expansion has only been around for a little more than 20 years.

    In 1917 when Albert Einstein applied his general theory of relativity to describe the universe as a whole, laying the foundations for the big bang theory, he and other leading scientists at that time conceived of the cosmos as static and nonexpanding. But in order to keep that universe from collapsing under the attractive force of gravity, he needed to introduce a repulsive force to counteract it: the cosmological constant.

    It wasn’t until 1929 when Edwin Hubble discovered that the universe is in fact expanding, and that galaxies farther from Earth are moving away faster than those that are closer, that the model of a static universe was finally abandoned.

    Even Einstein was quick to modify his theories, by the early 1930s publishing two new and distinct models of the expanding universe, both of them without the cosmological constant.

    But although astronomers had finally come to understand that the universe was expanding, and had more or less abandoned the concept of the cosmological constant, they also presumed that the universe was dominated by matter and that gravity would eventually cause its expansion to slow; the universe would either continue to expand forever, but ever-increasingly slowly, or it would at some point cease its expansion and then collapse, ending in a “big crunch.”

    “That’s the way we thought the universe worked, up until 1998,” said Professor of Astronomy and Astrophysics Robin Ciardullo, a founding member of HETDEX.

    That year, two independent teams — one led by Saul Perlmutter at DOE’s Lawrence Berkeley National Laboratory (US), and the other led by Brian Schmidt of the Australian National University (AU) and Adam Riess of the NASA Space Telescope Science Institute (US) — would nearly simultaneously publish astounding results showing that the expansion of the universe was in fact accelerating, driven by some mysterious antigravity force.

    Later that year, cosmologist Michael Turner of the University of Chicago (US) and DOE’s Fermi National Accelerator Laboratory (US) coined the term “dark energy” to describe this mysterious force.

    The discovery would be named Science magazine’s “Breakthrough of the Year” for 1998, and in 2011 Perlmutter, Schmidt and Reiss would be awarded the Nobel Prize in physics.

    Saul Perlmutter [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 and Adam Riess [The High-z Supernova Search Team] for providing evidence that the expansion of the universe is accelerating.

    Competing theories

    More than 20 years after the discovery of dark energy, astronomers still don’t know what, exactly, it is.

    “Whenever astronomers say ‘dark,’ that means we don’t have any clue about it,” Jeong said with a wry grin. “Dark energy is just another way of saying that we don’t know what’s causing this accelerating expansion.”

    There are, however, a number of theories that attempt to explain dark energy, and a few major contenders.

    Perhaps the most favored explanation is the previously abandoned cosmological constant, which modern-day physicists describe as vacuum energy. “The vacuum in physics is not a state of nothing,” Jeong explained. “It is a place where particles and antiparticles are continuously created and destroyed.” The energy produced in this perpetual cycle could exert an outward-pushing force on space itself, causing its expansion, initiated in the big bang, to accelerate.

    Unfortunately, the theoretical calculations of vacuum energy don’t match the observations — by a factor of as much as 10120, or a one followed by 120 zeroes. “That’s very, very unusual,” Jeong said, “but that’s where we’ll be if dark energy turns out to be constant.” Clearly this discrepancy is a major issue, and it could necessitate a reworking of current theory, but the cosmological constant in the form of vacuum energy is nonetheless the leading candidate so far.

    Another possible explanation is a new, yet-undiscovered particle or field that would permeate all of space; but so far, there’s no evidence to support this.

    A third possibility is that Einstein’s theory of gravity is incorrect. “If you start from the wrong equation,” Jeong said, “then you get the wrong answer.” There are alternatives to general relativity, but each has its own issues and none has yet displaced it as the reigning theory. For now, it’s still the best description of gravity we’ve got.

    Ultimately, what’s needed is more and better observational data — precisely what HETDEX was designed to collect like no other survey has done before.

    A map of stars and sound

    “HETDEX is very ambitious,” Ciardullo said. “It’s going to observe a million galaxies to map out the structure of the universe going over two-thirds of the way back to the beginning of time. We’re the only ones going out that far to see the dark energy component of the universe and how it’s evolving.”

    Ciardullo, an observational astronomer who studies everything from nearby stars to faraway galaxies and dark matter, is HETDEX’s observations manager. He’s quick to note, though, that he’s got help in that role (from Jeong and others) and that he and everyone else on the project wears more than one hat. “This is a very big project,” he said. “It’s over $40 million. But if you count heads, it’s not very many people. And so we all do more than one thing.”

    Jeong, a theoretical astrophysicist and cosmologist who also studies gravitational waves, was instrumental in laying the groundwork for the study and is heavily involved in the project’s data analysis — and he’s also helping Ciardullo determine where to point the 10-meter Hobby-Eberly Telescope, the world’s third largest. “It’s kind of interesting,” he noted with a chuckle, “a theorist telling observers where to look.”

    While other studies measure the universe’s expansion using distant supernovae or a phenomenon known as gravitational lensing, where light is bent by the gravity of massive objects such as galaxies and black holes, HETDEX is focused on sound waves from the big bang, called baryonic acoustic oscillations. Although we can’t actually hear sounds in the vacuum of space, astronomers can see the effect of these primordial sound waves in the distribution of matter throughout the universe.

    During the first 400,000-or-so years following the big bang, the universe existed as dense, hot plasma — a particle soup of matter and energy. Tiny disturbances called quantum fluctuations in that plasma set off sound waves, like ripples from a pebble tossed into a pond, which helped matter begin to clump together and form the universe’s initial structure. The result of this clumping is evident in the cosmic microwave background (also called the “afterglow” of the big bang), which is the first light, and the farthest back, that we can see in the universe. And it’s also imprinted in the distribution of galaxies throughout the universe’s history — like the ripples on our pond, frozen into space.

    “The physics of sound waves is pretty well known,” Ciardullo said. “You see how far these things have gone, you know how fast the sound waves have traveled, so you know the distance. You have a standard ruler on the universe, throughout cosmic history.”

    As the universe has expanded so has the ruler, and those variances in the ruler will show how the universe’s rate of expansion, driven by dark energy, has changed over time.

    “Basically,” Jeong said, “we make a three-dimensional map of galaxies and then measure it.”

    New discovery space

    To make their million-galaxy map, the HETDEX team needed a powerful new instrument.

    A set of more than 150 spectrographs called VIRUS (Visible Integral-Field Replicable Unit Spectrographs), mounted on the Hobby-Eberly Telescope, gathers the light from those galaxies into an array of some 35,000 optical fibers and then splits it into its component wavelengths in an ordered continuum known as a spectrum.

    Galaxies’ spectra reveal, among other things, the speed at which they are moving away from us — a measurement known as “redshift.” Due to the Doppler effect, the wavelength of an object moving away from its observer is stretched (think of a siren that gets lower in pitch as it speeds away), and an object moving toward its observer has its wavelength compressed, like that same siren increasing in pitch as it gets nearer. In the case of receding galaxies, their light is stretched and thus shifted toward the red end of the spectrum.

    Measuring this redshift allows the HETDEX team to calculate the distance to those galaxies and produce a precise three-dimensional map of their positions.

    Among the galaxies HETDEX is observing are what are known as Lyman-alpha galaxies — young star-forming galaxies that emit strong spectral lines at specific ultraviolet wavelengths.

    “We’re using Lyman-alpha-emitting galaxies as a ‘tracer particle,’” explained Research Professor of Astronomy and Astrophysics Caryl Gronwall, who is also a founding member of HETDEX. “They’re easy to find because they have a very strong emission line, which is easy to find spectroscopically with the VIRUS instrument. So we have this method that efficiently picks out galaxies at a fairly high redshift, and then we can measure where they are, measure their properties.”

    4
    The universe is expanding, and that expansion stretches light traveling through space in a phenomenon known as cosmological redshift. The greater the redshift, the greater the distance the light has traveled. As a result, telescopes with infrared detectors are needed to see light from the first, most distant galaxies.
    IMAGE: National Aeronautics Space Agency (US), European Space Agency [Agence spatiale européenne][Europäische Weltraumorganisation](EU), and L. Hustak (NASA Space Telescope Science Institute (US))

    See the full article here .

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Penn State Campus

    The Pennsylvania State University is a public state-related land-grant research university with campuses and facilities throughout Pennsylvania. Founded in 1855 as the Farmers’ High School of Pennsylvania, Penn State became the state’s only land-grant university in 1863. Today, Penn State is a major research university which conducts teaching, research, and public service. Its instructional mission includes undergraduate, graduate, professional and continuing education offered through resident instruction and online delivery. In addition to its land-grant designation, it also participates in the sea-grant, space-grant, and sun-grant research consortia; it is one of only four such universities (along with Cornell University(US), Oregon State University(US), and University of Hawaiʻi at Mānoa(US)). Its University Park campus, which is the largest and serves as the administrative hub, lies within the Borough of State College and College Township. It has two law schools: Penn State Law, on the school’s University Park campus, and Dickinson Law, in Carlisle. The College of Medicine is in Hershey. Penn State is one university that is geographically distributed throughout Pennsylvania. There are 19 commonwealth campuses and 5 special mission campuses located across the state. The University Park campus has been labeled one of the “Public Ivies,” a publicly funded university considered as providing a quality of education comparable to those of the Ivy League.
    Annual enrollment at the University Park campus totals more than 46,800 graduate and undergraduate students, making it one of the largest universities in the United States. It has the world’s largest dues-paying alumni association. The university offers more than 160 majors among all its campuses.

    Annually, the university hosts the Penn State IFC/Panhellenic Dance Marathon (THON), which is the world’s largest student-run philanthropy. This event is held at the Bryce Jordan Center on the University Park campus. The university’s athletics teams compete in Division I of the NCAA and are collectively known as the Penn State Nittany Lions, competing in the Big Ten Conference for most sports. Penn State students, alumni, faculty and coaches have received a total of 54 Olympic medals.

    Early years

    The school was sponsored by the Pennsylvania State Agricultural Society and founded as a degree-granting institution on February 22, 1855, by Pennsylvania’s state legislature as the Farmers’ High School of Pennsylvania. The use of “college” or “university” was avoided because of local prejudice against such institutions as being impractical in their courses of study. Centre County, Pennsylvania, became the home of the new school when James Irvin of Bellefonte, Pennsylvania, donated 200 acres (0.8 km2) of land – the first of 10,101 acres (41 km^2) the school would eventually acquire. In 1862, the school’s name was changed to the Agricultural College of Pennsylvania, and with the passage of the Morrill Land-Grant Acts, Pennsylvania selected the school in 1863 to be the state’s sole land-grant college. The school’s name changed to the Pennsylvania State College in 1874; enrollment fell to 64 undergraduates the following year as the school tried to balance purely agricultural studies with a more classic education.

    George W. Atherton became president of the school in 1882, and broadened the curriculum. Shortly after he introduced engineering studies, Penn State became one of the ten largest engineering schools in the nation. Atherton also expanded the liberal arts and agriculture programs, for which the school began receiving regular appropriations from the state in 1887. A major road in State College has been named in Atherton’s honor. Additionally, Penn State’s Atherton Hall, a well-furnished and centrally located residence hall, is named not after George Atherton himself, but after his wife, Frances Washburn Atherton. His grave is in front of Schwab Auditorium near Old Main, marked by an engraved marble block in front of his statue.

    Early 20th century

    In the years that followed, Penn State grew significantly, becoming the state’s largest grantor of baccalaureate degrees and reaching an enrollment of 5,000 in 1936. Around that time, a system of commonwealth campuses was started by President Ralph Dorn Hetzel to provide an alternative for Depression-era students who were economically unable to leave home to attend college.

    In 1953, President Milton S. Eisenhower, brother of then-U.S. President Dwight D. Eisenhower, sought and won permission to elevate the school to university status as The Pennsylvania State University. Under his successor Eric A. Walker (1956–1970), the university acquired hundreds of acres of surrounding land, and enrollment nearly tripled. In addition, in 1967, the Penn State Milton S. Hershey Medical Center, a college of medicine and hospital, was established in Hershey with a $50 million gift from the Hershey Trust Company.

    Modern era

    In the 1970s, the university became a state-related institution. As such, it now belongs to the Commonwealth System of Higher Education. In 1975, the lyrics in Penn State’s alma mater song were revised to be gender-neutral in honor of International Women’s Year; the revised lyrics were taken from the posthumously-published autobiography of the writer of the original lyrics, Fred Lewis Pattee, and Professor Patricia Farrell acted as a spokesperson for those who wanted the change.

    In 1989, the Pennsylvania College of Technology in Williamsport joined ranks with the university, and in 2000, so did the Dickinson School of Law. The university is now the largest in Pennsylvania. To offset the lack of funding due to the limited growth in state appropriations to Penn State, the university has concentrated its efforts on philanthropy.

     
  • richardmitnick 11:49 pm on March 3, 2021 Permalink | Reply
    Tags: "Will this solve the mystery of the expansion of the universe?", , , , , Dark Energy, , From the science paper: "We find the mean value of the present Hubble parameter in the NEDE model to be H0=71.4±1.0  km s−1 Mpc−1 (68% C.L.).", , Proposed "New early dark energy (NEDE)", South Danish University [Syddansk Universitet](DK)   

    From South Danish University [Syddansk Universitet](DK): “Will this solve the mystery of the expansion of the universe?” 

    From South Danish University [Syddansk Universitet](DK)

    Physicists’ new proposal that a new type of extra dark energy is involved is highlighted in scientific journal.

    3/2/2021
    Birgitte Svennevig

    1
    Credit: CC0 Public Domain.

    The universe was created by a giant bang; the Big Bang 13.8 billion years ago, and then it started to expand. The expansion is ongoing: it is still being stretched out in all directions like a balloon being inflated.

    Physicists agree on this much, but something is wrong. Measuring the expansion rate of the universe in different ways leads to different results.

    So, is something wrong with the methods of measurement? Or is something going on in the universe that physicists have not yet discovered and therefore have not taken into account?

    It could very well be the latter, according to several physicists, i.a. Martin S. Sloth, Professor of Cosmology at SDU.

    In a new scientific article, he and his SDU colleague, postdoc Florian Niedermannn, propose the existence of a new type of dark energy in the universe. If you include it in the various calculations of the expansion of the universe, the results will be more alike.

    – “A new type of dark energy can solve the problem of the conflicting calculations” says Martin S. Sloth.

    Conflicting measurements

    When physicists calculate the expansion rate of the universe, they base the calculation on the assumption that the universe is made up of dark energy, dark matter and ordinary matter. Until recently, all types of observations fitted in with such a model of the universe’s composition of matter and energy, but this is no longer the case.

    Conflicting results arise when looking at the latest data from measurements of supernovae and the cosmic microwave background radiation; the two methods quite simply lead to different results for the expansion rate.

    – “In our model, we find that if there was a new type of extra dark energy in the early universe, it would explain both the background radiation and the supernova measurements simultaneously and without contradiction” says Martin S. Sloth.

    From one phase to another

    – “We believe that in the early universe, dark energy existed in a different phase. You can compare it to when water is cooled and it undergoes a phase transition to ice with a lower density, he explains and continues:

    – “In the same way, dark energy in our model undergoes a transition to a new phase with a lower energy density, thereby changing the effect of the dark energy on the expansion of the universe”.

    According to Sloth and Niedermann’s calculations, the results add up if you imagine that dark energy thus underwent a phase transition triggered by the expansion of the universe.

    A very violent process

    – “It is a phase transition where many bubbles of the new phase suddenly appear, and when these bubbles expand and collide, the phase transition is complete. On a cosmic scale, it is a very violent quantum mechanical process” explains Martin S. Sloth.

    Today we know approx. 20 per cent of the matter that the universe is made of. It is the matter that you and I, planets and galaxies are made of. The universe also consists of Dark Matter, which no one knows what is.

    In addition, there is dark energy in the universe; it is the energy that causes the universe to expand, and it makes up approx. 70 pct. of the energy density of the universe.

    Science paper:
    New early dark energy
    Physical Review D

    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 South Danish University [Syddansk Universitet] is a university in Denmark that has campuses located in Southern Denmark and on Zealand.

    The university offers a number of joint programmes in co-operation with the Europe University of Flensburg [Universität Flensburg](DE) and the Christian-Albrecht University of Kiel [Christian-Albrechts-Universität zu Kiel](DE). Contacts with regional industries and the international scientific community are strong.

    With its 29,674 enrolled students (as of 2016), the university is both the third-largest and, given its roots in Odense University, the third-oldest Danish university (fourth if one includes the Technical University of Denmark). Since the introduction of the ranking systems in 2012, the South Danish University has consistently been ranked as one of the top 50 young universities in the world by both the Times Higher Education World University Rankings of the Top 100 Universities Under 50 and the QS World University Rankings of the Top 50 Universities Under 50.

    The South Danish University was established in 1998 when Odense University, the Southern Denmark School of Business and Engineering and the South Jutland University Centre were merged. The University Library of Southern Denmark was also merged with the university in 1998. As the original Odense University was established in 1966, the South Danish University celebrated their 50-year anniversary on September 15, 2016.

    In 2006, the Odense University College of Engineering was merged into the university and renamed as the Faculty of Engineering. After being located in different parts of Odense for several years, a brand new Faculty of Engineering building physically connected to the main Odense Campus was established and opened in 2015. In 2007, the Business School Centre in Slagelse (Handelshøjskolecentret Slagelse) and the National Institute of Public Health (Statens Institut for Folkesundhed) were also merged into the South Danish University.

     
  • richardmitnick 10:09 am on January 2, 2021 Permalink | Reply
    Tags: "Science of Matter; Energy; Space and Time", , Dark Energy, , , , , Strandard Model,   

    From DOE’s Fermi National Accelerator Laboratory: “Science of Matter, Energy, Space and Time” 

    FNAL Art Image
    FNAL Art Image by Angela Gonzales

    From DOE’s Fermi National Accelerator Laboratory , an enduring source of strength for the US contribution to scientific research world wide.

    05/01/2014 [Brought forward today-always useful]

    What is the world made of?

    1

    The building blocks

    Physicists have identified 13 building blocks that are the fundamental constituents of matter. Our everyday world is made of just three of these building blocks: the up quark, the down quark and the electron. This set of particles is all that’s needed to make protons and neutrons and to form atoms and molecules. The electron neutrino, observed in the decay of other particles, completes the first set of four building blocks.

    For some reason nature has elected to replicate this first generation of quarks and leptons to produce a total of six quarks and six leptons, with increasing mass. Like all quarks, the sixth quark, named top, is much smaller than a proton (in fact, no one knows how small quarks are), but the top is as heavy as a gold atom!

    Although there are reasons to believe that there are no more sets of quarks and leptons, theorists speculate that there may be other types of building blocks, which may partly account for the dark matter implied by astrophysical observations. This poorly understood matter exerts gravitational forces and manipulates galaxies. It will take Earth-based accelerator experiments to identify its fabric.

    The forces

    Scientists distinguish four elementary types of forces acting among particles: strong, weak, electromagnetic and gravitational force.

    The strong force is responsible for quarks “sticking” together to form protons, neutrons and related particles.
    The electromagnetic force binds electrons to atomic nuclei (clusters of protons and neutrons) to form atoms.
    The weak force facilitates the decay of heavy particles into smaller siblings.
    The gravitational force acts between massive objects. Although it plays no role at the microscopic level, it is the dominant force in our everyday life and throughout the universe.

    Particles transmit forces among each other by exchanging force-carrying particles called bosons. These force mediators carry discrete amounts of energy, called quanta, from one particle to another. You could think of the energy transfer due to boson exchange as something like the passing of a basketball between two players.

    Each force has its own characteristic bosons:

    The gluon mediates the strong force; it “glues” quarks together.
    The photon carries the electromagnetic force; it also transmits light.
    The W and Z bosons represent the weak force; they introduce different types of decays.

    Physicists expect that the gravitational force may also be associated with a boson particle. Named the graviton, this hypothetical boson is extremely hard to observe since, at the subatomic level, the gravitational force is many orders of magnitude weaker than the other three elementary forces.

    Table of particle discoveries: who, when, where?

    The Higgs boson

    The Higgs boson is a particle associated with the Higgs field, the mechanism through which elementary particles gain mass. Without the Higgs field, or something similar, atoms would not form, and there would be no chemistry, no biology and no life.

    The Higgs field is like a giant vat of molasses spread throughout the universe. Most of the known types of particles that travel through it stick to the molasses, which slows them down and makes them heavier. The Higgs boson is a particle that helps transmit the mass-giving Higgs force field, similar to the way a particle of light, the photon, transmits the electromagnetic field.

    The ATLAS and CMS experiments at CERN’s Large Hadron Collider in Geneva, Switzerland, announced the discovery of the Higgs particle in July 2012.

    CERN CMS Higgs Event May 27, 2012.


    CERN ATLAS Higgs Event
    June 12, 2012.

    Antimatter

    Although it is a staple of science fiction, antimatter is as real as matter. For every particle, physicists have discovered a corresponding antiparticle, which looks and behaves in almost the same way. Antiparticles, though, have the opposite properties of their corresponding particles. An antiproton, for example, has a negative electric charge while a proton is positively charged.

    In the mid-1990s, physicists at CERN (1995) and Fermilab (1996) created the first anti-atoms. To learn more about the properties of the antimatter world, they carefully added a positron (the antiparticle of an electron) to an antiproton. The result: antihydrogen.

    CERN map

    FNAL/Tevatron map

    Storing antimatter is a difficult task. As soon as an antiparticle and a particle meet, they annihilate, disappearing in a flash of energy. Using electromagnetic force fields, physicists are able to store antimatter inside vacuum vessels for a limited amount of time.

    WIMPS and Dark Matter

    No one has ever directly observed dark matter, but two clues led astronomers to suspect its existence. First, when researchers measured the masses of all the stars and planets that make up galaxies, they discovered that the gravity of those objects alone would not be great enough to hold them together. Something they could not see must have been contributing mass and therefore gravitational pull. Second, they observed in space the kind of distortions of light usually caused by large masses in areas that seemed empty.

    The composition of dark matter is unknown, and its existence shows that the Standard Model of particle physics is incomplete.

    Several theories of particle physics, such as supersymmetry, predict that weakly interacting massive particles, WIMPs, exist with properties suitable for explaining dark matter.

    Standard Model of Supersymmetry via DESY (DE).

    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, did most of the work on Dark Matter.

    Fritz Zwicky from http:// palomarskies.blogspot.com.

    Coma cluster via NASA/ESA Hubble.

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


    Vera Rubin, with Department of Terrestrial Magnetism (DTM) image tube spectrograph attached to the Kitt Peak 84-inch telescope, 1970. https://home.dtm.ciw.edu.

    Dark Energy

    In the 20th century, astronomers first discovered that the universe was getting bigger. They found this by observing something similar to the Doppler effect in the light coming from distant galaxies. The Doppler effect is what causes a car horn to change in pitch from high to low as it approaches and passes. This happens because the sound waves are compressed as the car moves toward you, resulting in a higher pitch, and are stretched as it recedes, resulting in a lower pitch. As an object approaches you, the light waves coming from it compress. Astronomers call this blueshift. When light waves stretch as an object moves farther away, astronomers call it redshift.

    By measuring the spectrum of an astronomical object, astronomers can tell how much the space between the object and observer has stretched as the light traveled through it. When astronomer Vesto Slipher measured light coming from other galaxies, he found that almost all were redshifted, or moving away. He found that those that seemed dimmer and farther away had even higher redshifts. The universe was expanding. This led astronomers to the idea of the big bang.

    Astronomers assumed, however, that the force of gravity from all of the matter in the universe would slow the expansion. They were in for a surprise in 1998 when they discovered that the expansion was actually speeding up. Astronomers discovered this when they measured the brightness of the light coming from a certain type of supernova that always explodes with roughly the same energy. The dimmer the light from the supernova, the farther the distance it had traveled to Earth. They discovered that the supernovae were farther away than their redshift measurements predicted. The universe was expanding at an accelerating rate.

    Some particle astrophysicists think this is happening because a force with a repulsive gravity is pushing the universe apart. They call this force Dark Energy.

    Dark Energy Survey


    Dark Energy Camera [DECam], built at FNAL


    NOAO/CTIO Victor M Blanco 4m Telescope which houses the DECam at Cerro Tololo, Chile, housing DECam at an altitude of 7200 feet

    Timeline of the Inflationary Universe WMAP

    The Dark Energy Survey (DES) 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. DES began searching the Southern skies on August 31, 2013.

    According to 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. 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.

    DES 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 DES 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.

    The Standard Model

    Standard Model of Particle Physics via http://www.plus.maths.org .

    Standard Model of Particle Fever via “Particle Fever” movie.

    Physicists call the theoretical framework that describes the interactions between elementary building blocks (quarks and leptons) and the force carriers (bosons) the Standard Model. Gravity is not yet part of this framework, and a central question of 21st-century particle physics is the search for a quantum formulation of gravity that could be included in the Standard Model.

    Though still called a model, the Standard Model is a fundamental and well-tested physics theory. Physicists use it to explain and calculate a vast variety of particle interactions and quantum phenomena. High-precision experiments have repeatedly verified subtle effects predicted by the Standard Model.

    So far, the biggest success of the Standard Model is the unification of the electromagnetic and the weak forces into the so-called electroweak force. The consolidation is a milestone comparable to the unification of the electric and the magnetic forces into a single electromagnetic theory by J.C. Maxwell in the 19th century. Physicists think it is possible to describe all forces with a Grand Unified Theory.

    See the full here.


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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    FNAL Icon

    Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics. Fermilab is America’s premier laboratory for particle physics and accelerator research, funded by the U.S. Department of Energy. Thousands of scientists from universities and laboratories around the world
    collaborate at Fermilab on experiments at the frontiers of discovery.

     
  • richardmitnick 9:40 am on December 22, 2020 Permalink | Reply
    Tags: "SURF formally creates research user association", , , , , Dark Energy, , , , , , ,   

    From Sanford Underground Research Facility-SURF: “SURF formally creates research user association” 

    SURF-Sanford Underground Research Facility, Lead, South Dakota, USA.


    From Sanford Underground Research Facility-SURF

    Homestake Mining, Lead, South Dakota, USA.


    Homestake Mining Company

    December 21, 2020
    Erin Lorraine Broberg

    1
    Researchers explore the fields particle physics, earth and life sciences at Sanford Lab.
    Photo credits: by Nick Hubbard and Matthew Kapust.

    User association fosters communication between users and SURF, promotes the case for underground science on the world stage.

    As the nation’s deepest underground laboratory, Sanford Underground Research Facility (SURF) serves as a touchstone for the scientific community. Under nearly a mile of rock, physicists shield their sensitive experiments from the cacophony of cosmic rays from the Sun. Biologists hike through miles of drifts to far-off collection sites, gathering samples of water swimming with microscopic life forms called extremophiles. And geologists get the coveted experience of scrutinizing deep rock layers face-to-face.

    This year, SURF formally created the SURF User Association (Association) to bring these researchers together. The Association, which currently has 288 active members, aims to promote open discussion between users and SURF management and foster community between users of diverse disciplines.

    “As a research institution, it’s important that we have a vehicle to connect with researchers on a consistent basis,” said Jaret Heise, science director at SURF. Heise noted that communication channels existed previously, but the creation of a formal user association invites even greater participation from users.

    The Association also encourages users to act as ambassadors for underground science at SURF on the world stage.

    “As science communities define their priorities for the next decade, SURF and the scientists that perform research at our facility have a voice in that strategic planning,” Heise said. “Our users can advocate for the importance of underground science, and in particular they can advocate for the SURF facility as a location for future underground science.”

    In December, the Association selected nine members to serve on the Executive Committee, which will conduct day-to-day business. The Executive Committee includes early career researchers, as well as representatives from physics, earth and life sciences, and six experiments operating at SURF.

    Megan Smith, an earth scientist at Lawrence Livermore National Laboratory, is a member of the Association’s inaugural Executive Committee. Smith studies the Earth’s deep subsurface to better understand the potential of geothermal energy. In her field, direct access to deep underground rock is extremely valuable.

    “As geologists, we only get a tiny, tiny sampling of what’s under the surface of the earth. We have to use small data points to make inferences about processes that occur at different depths and pressures,” Smith said. “The ability to examine the subsurface is invaluable. It hugely expands our capabilities to test our models of the Earth.”

    As a member of EGS Collab/SIGMA-V, Smith has traveled to SURF multiple times since 2017. On Smith’s first trip, the team found a promising location for their experiment. On subsequent expeditions underground, they lined the drift with sensitive instruments to track how water travels through small pathways in the rock. Over the years, these tests have been instrumental in analyzing and refining the group’s models of the subsurface, informing future geothermal energy projects.

    Smith recognized the importance of acting as an ambassador for underground science facilities.

    “Working at SURF is an incredible opportunity. There are so many cool science questions that can only be answered in this type of space,” Smith said.

    Ralph Massarczyk, a physicist at Los Alamos National Laboratory (LANL), is also a member of the SURF User Association’s Executive Committee. He began traveling to SURF six years ago, when he was a postdoc helping with the early construction of the Majorana Demonstrator [below].

    Now a staff scientist at LANL, Massarczyk describes the growth he has seen at SURF: “From a researcher’s standpoint, things have become more user-friendly through the years. This Association will help users, especially the younger researchers, to have a point of contact to ask questions about how things work at SURF.”

    Massarczyk said he looks forward to sharing research opportunities at SURF with colleagues in Europe, who may not know much about the facility. “SURF is getting more and more international, and this association is a nice podium for me to help spread out the word,” Massarczyk said.

    Massarczyk noted that SURF is garnering local attention, too.

    “The first time I came to Lead, I remember going to a restaurant and talking with locals. When they heard I worked at the lab, they would tell me which level they used to work on when it was a mine,” Massarczyk recalls. “Now, when I talk with people, they ask which experiment I’m with, and when I say ‘Majorana,’ they know the name. They’re familiar with the experiments. I would say the lab has helped shaped the town. It went from a mining town to people being excited about the science.”

    Moving forward, the SURF User Association aims to connect and support our research communities, whether they are studying subatomic particles, microscopic extremophiles, vibrations in the rock and other questions for which the underground environment is a unique window.

    For more information about the SURF User Association, visit our website: https://www.sanfordlab.org/researchers

    See the full article here .


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

    Stem Education Coalition

    About us: The Sanford Underground Research Facility-SURF in Lead, South Dakota, advances our understanding of the universe by providing laboratory space deep underground, where sensitive physics experiments can be shielded from cosmic radiation. Researchers at the Sanford Lab explore some of the most challenging questions facing 21st century physics, such as the origin of matter, the nature of dark matter and the properties of neutrinos. The facility also hosts experiments in other disciplines—including geology, biology and engineering.

    The Sanford Lab is located at the former Homestake gold mine, which was a physics landmark long before being converted into a dedicated science facility. Nuclear chemist Ray Davis earned a share of the Nobel Prize for Physics in 2002 for a solar neutrino experiment he installed 4,850 feet underground in the mine.

    Homestake closed in 2003, but the company donated the property to South Dakota in 2006 for use as an underground laboratory. That same year, philanthropist T. Denny Sanford donated $70 million to the project. The South Dakota Legislature also created the South Dakota Science and Technology Authority to operate the lab. The state Legislature has committed more than $40 million in state funds to the project, and South Dakota also obtained a $10 million Community Development Block Grant to help rehabilitate the facility.

    In 2007, after the National Science Foundation named Homestake as the preferred site for a proposed national Deep Underground Science and Engineering Laboratory (DUSEL), the South Dakota Science and Technology Authority (SDSTA) began reopening the former gold mine.

    In December 2010, the National Science Board decided not to fund further design of DUSEL. However, in 2011 the Department of Energy, through the Lawrence Berkeley National Laboratory, agreed to support ongoing science operations at Sanford Lab, while investigating how to use the underground research facility for other longer-term experiments. The SDSTA, which owns Sanford Lab, continues to operate the facility under that agreement with Berkeley Lab.

    The first two major physics experiments at the Sanford Lab are 4,850 feet underground in an area called the Davis Campus, named for the late Ray Davis. The Large Underground Xenon (LUX) experiment is housed in the same cavern excavated for Ray Davis’s experiment in the 1960s.

    LBNL LZ project at SURF, Lead, SD, USA, will replace LUX at SURF

    In October 2013, after an initial run of 80 days, LUX was determined to be the most sensitive detector yet to search for dark matter—a mysterious, yet-to-be-detected substance thought to be the most prevalent matter in the universe. The Majorana Demonstrator experiment, also on the 4850 Level, is searching for a rare phenomenon called “neutrinoless double-beta decay” that could reveal whether subatomic particles called neutrinos can be their own antiparticle. Detection of neutrinoless double-beta decay could help determine why matter prevailed over antimatter. The Majorana Demonstrator experiment is adjacent to the original Davis cavern.

    LUX’s mission was to scour the universe for WIMPs, vetoing all other signatures. It would continue to do just that for another three years before it was decommissioned in 2016.

    In the midst of the excitement over first results, the LUX collaboration was already casting its gaze forward. Planning for a next-generation dark matter experiment at Sanford Lab was already under way. Named LUX-ZEPLIN (LZ), the next-generation experiment would increase the sensitivity of LUX 100 times.

    SLAC physicist Tom Shutt, a previous co-spokesperson for LUX, said one goal of the experiment was to figure out how to build an even larger detector.
    “LZ will be a thousand times more sensitive than the LUX detector,” Shutt said. “It will just begin to see an irreducible background of neutrinos that may ultimately set the limit to our ability to measure dark matter.”
    We celebrate five years of LUX, and look into the steps being taken toward the much larger and far more sensitive experiment.

    Another major experiment, the Long Baseline Neutrino Experiment (LBNE)—a collaboration with Fermi National Accelerator Laboratory (Fermilab) and Sanford Lab, is in the preliminary design stages. The project got a major boost last year when Congress approved and the president signed an Omnibus Appropriations bill that will fund LBNE operations through FY 2014. Called the “next frontier of particle physics,” LBNE will follow neutrinos as they travel 800 miles through the earth, from FermiLab in Batavia, Ill., to Sanford Lab.

    FNAL LBNE/DUNE from FNAL to SURF, Lead, South Dakota, USA


    LBNE

    U Washington Majorana Demonstrator Experiment at SURF

    The MAJORANA DEMONSTRATOR will contain 40 kg of germanium; up to 30 kg will be enriched to 86% in 76Ge. The DEMONSTRATOR will be deployed deep underground in an ultra-low-background shielded environment in the Sanford Underground Research Facility (SURF) in Lead, SD. The goal of the DEMONSTRATOR is to determine whether a future 1-tonne experiment can achieve a background goal of one count per tonne-year in a 4-keV region of interest around the 76Ge 0νββ Q-value at 2039 keV. MAJORANA plans to collaborate with GERDA for a future tonne-scale 76Ge 0νββ search.

    CASPAR at SURF.

    CASPAR experiment target at SURF.

    CASPAR is a low-energy particle accelerator that allows researchers to study processes that take place inside collapsing stars.

    The scientists are using space in the Sanford Underground Research Facility (SURF) in Lead, South Dakota, to work on a project called the Compact Accelerator System for Performing Astrophysical Research (CASPAR). CASPAR uses a low-energy particle accelerator that will allow researchers to mimic nuclear fusion reactions in stars. If successful, their findings could help complete our picture of how the elements in our universe are built. “Nuclear astrophysics is about what goes on inside the star, not outside of it,” said Dan Robertson, a Notre Dame assistant research professor of astrophysics working on CASPAR. “It is not observational, but experimental. The idea is to reproduce the stellar environment, to reproduce the reactions within a star.”

     
  • richardmitnick 6:21 pm on December 1, 2020 Permalink | Reply
    Tags: "Hobby-Eberly Telescope Dark Energy Experiment survey begins full operations", , , , , Dark Energy, ,   

    From Pennsylvania State University and University of Texas at Austin: “Hobby-Eberly Telescope Dark Energy Experiment survey begins full operations” 

    Penn State Bloc

    From Pennsylvania State University

    and

    U Texas Austin bloc

    From University of Texas at Austin

    December 01, 2020
    Rebecca Johnson and Sam Sholtis

    Media Contacts
    Donald Schneider
    dps@astro.psu.edu
    Work Phone: 814-863-9554

    Robin Ciardullo
    rbc3@psu.edu
    Work Phone: (814) 404-8626

    Caryl Gronwall
    caryl.gronwall@psu.edu
    Work Phone: (814) 404-1950

    Donghui Jeong
    djeong@psu.edu
    Work Phone: (512) 879-7806

    Sam Sholtis
    sjs144@psu.edu
    Work Phone: 814-865-1390

    U Texas McDonald Observatory Hobby-Eberly 9.1 meter Telescope, Altitude 2,070 m (6,790 ft)

    U Texas at Austin McDonald Observatory, Altitude 2,070 m (6,790 ft).

    Three years after its initial test observations, the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX) is now training its full suite of instrumentation to reveal the nature and evolution of dark energy, the mysterious entity that is the primary constituent of the universe.

    HETDEX, which is a large international consortium led by the University of Texas at Austin and involves approximately 100 scientists including Penn State researchers, plans to construct one of the largest maps of the cosmos ever made. The three-dimensional map of 2.5 million galaxies will help astronomers to better understand why the expansion of the universe is currently accelerating.

    “Penn State is delighted to be a participant in this fundamental scientific investigation,” said Donald Schneider, a member of the Hobby-Eberly Telescope (HET) Board of Directors and distinguished professor and head of Penn State’s Department of Astronomy and Astrophysics. “The telescope’s innovative design was by two Penn State astronomers, Lawrence Ramsey and Daniel Weedman, and a number of Penn State astronomers are playing important roles in the observations and data analysis in HETDEX.”

    2
    The two black structures to the left and right of the Hobby-Eberly Telescope’s main mirror are nicknamed ‘saddlebags.’ They hold the dozens of spectrographs that make up the VIRUS instrument designed to undertake HETDEX, the Hobby-Eberly Telescope Dark Energy Experiment. Credit: Ethan Tweedie Photography.

    HETDEX is using the 10-meter HET, located at McDonald Observatory in western Texas, to obtain data from two large regions of the sky; one field is in the direction of the Big Dipper, the other is slightly southwest of the constellation of Orion. Each time the telescope is pointed at these regions, which typically last 20 minutes, HETDEX’s instrumentation records approximately 32,000 spectra, capturing the cosmic fingerprint of the light from every object within the 10-meter telescope’s field of view.

    “HETDEX has arrived,” said University of Texas astronomer Karl Gebhardt, who is the survey’s project scientist. “We’re over a third of the way through our program now, and we have this fantastic dataset that we’re going to use to measure the dark energy evolution.”

    HETDEX is a “blind” survey; rather than pointing at specific targets, it records light from all sources over a specific patch of sky. These spectra are recorded via 32,000 optical fibers that feed into more than 100 instruments working together as a single spectrograph. This assembly, the Visible Integral-field Replicable Unit Spectrograph (VIRUS), is a complex system consisting of dozens of copies of an instrument working together for efficiency. VIRUS was designed and built especially for HETDEX.

    Building VIRUS “was quite a task to orchestrate,” said Gary Hill, a University of Texas astronomer and the designer of the instrument. “It’s the largest on many measures,” he said, noting that it has the most optical fibers, as well as having as much detector area as the largest astronomical cameras. VIRUS is also an extremely imposing instrument, claiming much of the volume inside the telescope dome.

    3
    This image shows the ‘focal surface’ of the Hobby-Eberly Telescope, where the optical fibers of VIRUS are arrayed. The circles each contain a square grid of 448 fibers. When the telescope is pointed and VIRUS takes an observation, each of the 32,000 fibers takes a spectrum simultaneously, recording a vast array of information on the speed, direction, and chemical makeup of every point inside the field of view, which is about the size of the full Moon.
    Credit: J. Pautzke/E. Mrozinski/G. Hill/HETDEX Collaboration.

    The HETDEX team expects to complete their observations by December 2023. In total, the completed survey will include one billion spectra, “the largest ever spectral survey by far,” Gebhardt said.

    “To investigate the properties of dark matter and its evolution, we must identify a few million galaxies of a specific type in the roughly one billion HETDEX spectra and create a map of their three-dimensional distribution,” explained Donghui Jeong, associate professor of astronomy and astrophysics at Penn State and leader of the HETDEX science group investigating large scale structures in the universe. “By examining the locations of these galaxies, we can compare the observations to models of dark energy and determine the influence of ordinary matter, dark matter, and dark energy at various points in the history of the universe.”

    Other Penn State HETDEX participants include Professor of Astronomy and Astrophysics Robin Ciardullo, who is the observations manager for HETDEX; Research Professor Caryl Gronwall; and Associate Professor Derek Fox.

    “The galaxies that will be studied in HETDEX are from the universe’s distant past,” said Gronwall. “The light we detect left these objects approximately ten billion years ago, when the universe was but a few billion years of age.”

    4
    This false-color image of the Pinwheel Galaxy (Messier 101) shows the power of the VIRUS instrument built for the HETDEX survey. The image is a mosaic made up of the central portion of 21 VIRUS pointings across a region of sky about half the size of the full Moon, with some small gaps in coverage. The colors show the contrast between young stars (blue/white) and older stars (red/orange). The breakout boxes show just four examples of the ‘cosmic fingerprint’ of objects in this view. Clockwise from top left: a white dwarf in our galaxy, an active galaxy 11 billion light-years away, a star-forming region in the Pinwheel Galaxy 20 million light-years away, and a star-forming galaxy 3 billion light-years away.
    Credit: G. Zeimann/HETDEX Collaboration.

    Taft Armandroff, director of The University of Texas at Austin’s McDonald Observatory and Chair of the HET Board of Directors, noted, “HETDEX represents the coming together of many astronomers and institutions to conduct the first major study of how dark energy changes over time.”

    HETDEX is led by The University of Texas at Austin McDonald Observatory and Department of Astronomy with participation from Penn State; Ludwig Maximilians University, Munich (DE); the Max Planck Institute for Extraterrestrial Physics (DE); the Institute for Astrophysics, Gottingen (DE); the Leibniz Institute for Astrophysics, Potsdam (DE); Texas A&M University; The University of Oxford (UK); the Max Planck Institute for Astrophysics (DE); The University of Tokyo (JP); and the Missouri University of Science and Technology.

    See the full article here .

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    U Texas at Austin

    U Texas Austin campus

    In 1839, the Congress of the Republic of Texas ordered that a site be set aside to meet the state’s higher education needs. After a series of delays over the next several decades, the state legislature reinvigorated the project in 1876, calling for the establishment of a “university of the first class.” Austin was selected as the site for the new university in 1881, and construction began on the original Main Building in November 1882. Less than one year later, on Sept. 15, 1883, University of Texas at Austin opened with one building, eight professors, one proctor, and 221 students — and a mission to change the world. Today, UT Austin is a world-renowned higher education, research, and public service institution serving more than 51,000 students annually through 18 top-ranked colleges and schools.

    Penn State Campus

    About Penn State

    WHAT WE DO BEST

    We teach students that the real measure of success is what you do to improve the lives of others, and they learn to be hard-working leaders with a global perspective. We conduct research to improve lives. We add millions to the economy through projects in our state and beyond. We help communities by sharing our faculty expertise and research.

    Penn State lives close by no matter where you are. Our campuses are located from one side of Pennsylvania to the other. Through Penn State World Campus, students can take courses and work toward degrees online from anywhere on the globe that has Internet service.

    We support students in many ways, including advising and counseling services for school and life; diversity and inclusion services; social media sites; safety services; and emergency assistance.

    Our network of more than a half-million alumni is accessible to students when they want advice and to learn about job networking and mentor opportunities as well as what to expect in the future. Through our alumni, Penn State lives all over the world.

    The best part of Penn State is our people. Our students, faculty, staff, alumni, and friends in communities near our campuses and across the globe are dedicated to education and fostering a diverse and inclusive environment.

     
  • richardmitnick 11:02 am on September 18, 2020 Permalink | Reply
    Tags: "The Big Freeze: How the universe will die", , , , , , Dark Energy,   

    From Astronomy Magazine: “The Big Freeze: How the universe will die” 

    From Astronomy Magazine

    September 10, 2020
    Eric Betz

    The cosmos will come to a close through a cold and lonely death called the Big Freeze.

    1
    The region surrounding Sagittarius A*, the Milky Way’s own supermassive black hole. Eventually, black holes will be the last remaining matter in the universe. Credit: NASA/JPL-Caltech/Judy Schmidt.

    The cosmos may never end. But if you were immortal, you’d probably wish it would. Our cosmos’ final fate is a long and frigid affair that astronomers call the Big Freeze, or Big Chill.

    It’s a fitting description for the day when all heat and energy is evenly spread over incomprehensibly vast distances. At this point, the universe’s final temperature will hover just above absolute zero.

    The Big Bang’s accelerating expansion

    Some 13.8 billion years ago, our universe was born in the Big Bang, and it’s been expanding ever since.

    Until a few decades ago, it looked like that expansion would eventually end. Astronomers’ measurements suggested there was enough matter in the universe to overcome expansion and reverse the process, triggering a so-called Big Crunch. In this scenario, the cosmos would collapse back into an infinitely dense singularity like the one it emerged from. Perhaps this process could even spark another Big Bang, the thinking went.

    We’d be gone, but the Big Bang/Big Crunch cycle could infinitely repeat.

    In the years since then, the discovery of dark energy has robbed us of a shot at this eternal rebirth. In 1998, two separate teams of astronomers announced that they’d measured special exploding stars in the distant universe, called a type Ia supernova, which serves as “standard candles” for calculating distances. They found that the distant explosions — which should all have the same intrinsic brightness — were dimmer, and therefore farther away, than expected. Some mysterious force was pushing the cosmos apart from within.

    This dark energy is now thought to make up some 69 percent of the universe’s mass, while dark matter accounts for another roughly 26 percent. Normal matter — people, planets, stars, and anything else you can see — comprises just about 5 percent of the cosmos.

    The most important impact of dark energy is that the universe’s expansion will never slow down. It will only accelerate.

    Heat death of the universe

    Decades of observations have only confirmed researchers’ findings. All signs now point to a long and lonely death that peters out toward infinity. The scientific term for this fate is “heat death.”

    But things will be rather desolate long before that happens.

    “Just” a couple trillion years from now, the universe will have expanded so much that no distant galaxies will be visible from our own Milky Way, which will have long since merged with its neighbors. Eventually, 100 trillion years from now, all star formation will cease, ending the Stelliferous Era that’s be running since not long after our universe first formed.

    Much later, in the so-called Degenerate Era, galaxies will be gone, too. Stellar remnants will fall apart. And all remaining matter will be locked up inside black holes.

    In fact, black holes will be the last surviving sentinels of the universe as we know it. In the Black Hole Era, they’ll be the only “normal” matter left. But eventually, even these titans will disappear, too.

    Stephen Hawking predicted that black holes slowly evaporate by releasing their particles into the universe. First, the smaller, solar-mass black holes will vanish. And by a googol years into the future (a 1 followed by 100 zeroes), Hawking radiation will have killed off even the supermassive black holes.

    No normal matter will remain in this final “Dark Era” of the universe, which will last far longer than everything that came before it. And the second law of thermodynamics tells us that in this time frame, all energy will ultimately be evenly distributed. The cosmos will settle at its final resting temperature, just above absolute zero, the coldest temperature possible.

    If this future seems dark and depressing, take comfort in knowing that every earthling will have died long before we have to worry about it. In fact, on this timescale of trillions of years, even the existence of our entire species registers as but a brief ray of sunlight before an infinite winter of darkness.

    See the full article here .


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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Astronomy is a magazine about the science and hobby of astronomy. Based near Milwaukee in Waukesha, Wisconsin, it is produced by Kalmbach Publishing. Astronomy’s readers include those interested in astronomy and those who want to know about sky events, observing techniques, astrophotography, and amateur astronomy in general.

    Astronomy was founded in 1973 by Stephen A. Walther, a graduate of the University of Wisconsin–Stevens Point and amateur astronomer. The first issue, August 1973, consisted of 48 pages with five feature articles and information about what to see in the sky that month. Issues contained astrophotos and illustrations created by astronomical artists. Walther had worked part time as a planetarium lecturer at the University of Wisconsin–Milwaukee and developed an interest in photographing constellations at an early age. Although even in childhood he was interested to obsession in Astronomy, he did so poorly in mathematics that his mother despaired that he would ever be able to earn a living. However he graduated in Journalism from the University of Wisconsin Stevens Point, and as a senior class project he created a business plan for a magazine for amateur astronomers. With the help of his brother David, he was able to bring the magazine to fruition. He died in 1977.

     
  • richardmitnick 11:14 am on September 9, 2020 Permalink | Reply
    Tags: "Lead Lab Selected for Next-Generation Cosmic Microwave Background Experiment", , , , , CMB-S4 project will feature new telescopes at the South Pole and also in Chile’s Atacama high desert., CMB-S4 will unite several existing collaborations to survey the microwave sky in unprecedented detail with 500000 ultrasensitive detectors for 7 years., , Dark Energy, , , This project will involve 21 telescopes in two of our planet’s prime places for viewing deep space.   

    From Lawrence Berkeley National Lab: “Lead Lab Selected for Next-Generation Cosmic Microwave Background Experiment” 

    From Lawrence Berkeley National Lab

    September 9, 2020
    Glenn Roberts Jr.
    geroberts@lbl.gov
    (510) 520-0843

    U.S. DOE selects Berkeley Lab to lead DOE/NSF experiment that combines observatories at the South Pole and in Chile’s Atacama high desert.

    1
    The South Pole Telescope scans the sky as the southern lights, or aurora australis, form green patterns in this 2018 video clip. The CMB-S4 project will feature new telescopes around this site of current experiments at the South Pole, and also in Chile’s Atacama high desert. (Credit: Robert Schwarz/University of Minnesota.)

    The largest collaborative undertaking yet to explore the relic light emitted by the infant universe has taken a step forward with the U.S. Department of Energy’s selection of Lawrence Berkeley National Laboratory (Berkeley Lab) to lead the partnership of national labs, universities, and other institutions that will carry out the DOE roles and responsibilities for the effort. This next-generation experiment, known as CMB-S4, or Cosmic Microwave Background Stage 4, is being planned to become a joint DOE and National Science Foundation project.

    2
    The ‘Stage-4’ ground-based cosmic microwave background (CMB) experiment, CMB-S4, consisting of dedicated telescopes equipped with highly sensitive superconducting cameras operating at the South Pole, the high Chilean Atacama plateau, and possibly northern hemisphere sites, will provide a dramatic leap forward in our understanding of the fundamental nature of space and time and the evolution of the Universe. CMB-S4 will be designed to cross critical thresholds in testing inflation, determining the number and masses of the neutrinos, constraining possible new light relic particles, providing precise constraints on the nature of dark energy, and testing general relativity on large scales.

    CMB-S4 will unite several existing collaborations to survey the microwave sky in unprecedented detail with 500,000 ultrasensitive detectors for 7 years. These detectors will be placed on 21 telescopes in two of our planet’s prime places for viewing deep space: the South Pole and the high Chilean Atacama desert. The project is intended to unlock many secrets in cosmology, fundamental physics, astrophysics, and astronomy.

    Combining a mix of large and small telescopes at both sites, CMB-S4 will be the first experiment to access the entire scope of ground-based CMB science. It will measure ever-so-slight variations in the temperature and polarization, or directionality, of microwave light across most of the sky, to probe for ripples in space-time associated with a rapid expansion at the start of the universe known as Inflation.

    Inflation

    4
    Alan Guth, from Highland Park High School and M.I.T., who first proposed cosmic inflation

    HPHS Owls

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


    Alan Guth’s notes:

    Alan Guth’s original notes on inflation

    3
    This image, from “Eternal Sky,” a video series about the Simons Observatory, shows the Atacama Desert site where some of the telescopes for the CMB-S4 experiment will be built. (Credit: Copyright Debra Kellner/Simons Foundation.)

    CMB-S4 will also help to measure the mass of the neutrino; map the growth of matter clustering over time in the universe; shed new light on mysterious Dark Matter, which makes up most of the universe’s matter but hasn’t yet been directly observed, and Dark Energy, which is driving an accelerating expansion of the universe; and aid in the detection and study of powerful space phenomena like gamma-ray bursts and jet-emitting blazars.

    Gamma-ray burst credit NASA SWIFT/Cruz Dewilde.

    NASA Neil Gehrels Swift Observatory.

    On Sept. 1, DOE Office of Science Director Chris Fall authorized the selection of Berkeley Lab as the lead laboratory for the DOE roles and responsibilities on CMB-S4, with Argonne National Laboratory, Fermi National Accelerator Laboratory, and SLAC National Accelerator Laboratory serving as partner labs.

    The CMB-S4 collaboration now numbers 236 members at 93 institutions in 14 countries and 21 U.S. states.

    The project passed its first DOE milestone, known as Critical Decision 0 or CD-0, on July 26, 2019. It has been endorsed by the 2014 report of the Particle Physics Project Prioritization Panel (known as P5), which helps to set the future direction of particle physics-related research. The project also was recommended in the National Academy of Sciences Strategic Vision for Antarctic Science in 2015, and by the Astronomy and Astrophysics Advisory Committee in 2017.

    Berkeley Lab Director Michael Witherell said, “The community of CMB scientists has come together to form a strong collaboration with a unified vision of what is needed for the next generation of discovery,” adding, “We will work with the universities and other laboratories, supported by the DOE and the NSF, to turn this vision into a CMB observatory that has unprecedented power and resolution.”

    5
    A view of the South Pole Telescope, one of the existing instruments at the South Pole site where CMB-S4 will be built. (Credit: Argonne National Laboratory.)

    The NSF has been key to the development of CMB-S4, which builds on NSF’s existing program of university-led, ground-based CMB experiments. Four of these experiments – the Atacama Cosmology Telescope and POLARBEAR/Simons Array in Chile, and the South Pole Telescope and BICEP/Keck at the South Pole – helped to start CMB-S4 in 2013, and the design of CMB-S4 relies heavily on technologies developed and deployed by these teams and others.

    Princeton Atacama Cosmology Telescope, on Cerro Toco in the Atacama Desert in the north of Chile, near the Llano de Chajnantor Observatory, Altitude 4,800 m (15,700 ft).

    Princeton ACT Telescope, on Cerro Toco in the Atacama Desert in the north of Chile, near the Llano de Chajnantor Observatory, Altitude 4,800 m (15,700 ft).

    POLARBEAR McGill Telescope located in the Atacama Desert of northern Chile in the Antofagasta Region. The POLARBEAR experiment is mounted on the Huan Tran Telescope (HTT) at the James Ax Observatory in the Chajnantor Science Reserve.

    BICEP 3 at the South Pole.

    NSF is also helping to plan its possible future role with a grant awarded to the University of Chicago.

    The CMB-S4 collaboration was established in 2018, and its current co-spokespeople are Julian Borrill, head of the Computational Cosmology Center at Berkeley Lab and a researcher at UC Berkeley’s Space Sciences Laboratory, and John Carlstrom, a professor of physics, astronomy, and astrophysics at the University of Chicago and scientist at Argonne Lab.

    CMB-S4 builds on decades of experience with ground-based, satellite, and balloon-based experiments, and Berkeley Lab has had a prominent role in CMB research for decades, noted Natalie Roe, Berkeley Lab’s associate laboratory director for the Physical Sciences Area.

    Berkeley Lab’s George Smoot, for example, shared the Nobel Prize in Physics in 2006 for leading a research team that discovered ever-slight temperature variations in the CMB light.

    Adrian Lee, a Berkeley Lab physicist and UC Berkeley professor, has served on the leadership teams for a number of precursor experiments to CMB-S4, including POLARBEAR/Simons Array and the Simons Observatory. Lee noted that the Simons Observatory and POLARBEAR have contributed design elements that are relevant to CMB-S4 – such as in the areas of optics and cryogenics.

    Borrill pioneered the use of supercomputers for CMB data analysis, led data management for the CMB research community for the past two decades at the DOE’s National Energy Research Scientific Computing Center (NERSC), and has served as the U.S. computational systems architect for the European Space Agency/NASA Planck satellite mission, which probed the CMB in great detail.

    NERSC at LBNL

    NERSC Cray Cori II supercomputer, named after Gerty Cori, the first American woman to win a Nobel Prize in science

    NERSC Hopper Cray XE6 supercomputer, named after Grace Hopper, One of the first programmers of the Harvard Mark I computer

    NERSC Cray XC30 Edison supercomputer

    NERSC GPFS for Life Sciences


    The Genepool system is a cluster dedicated to the DOE Joint Genome Institute’s computing needs. Denovo is a smaller test system for Genepool that is primarily used by NERSC staff to test new system configurations and software.

    NERSC PDSF computer cluster in 2003.

    PDSF is a networked distributed computing cluster designed primarily to meet the detector simulation and data analysis requirements of physics, astrophysics and nuclear science collaborations.

    Future:

    Cray Shasta Perlmutter SC18 AMD Epyc Nvidia pre-exascale supeercomputer

    NERSC is a DOE Office of Science User Facility.

    CMB per ESA/Planck

    ESA/Planck 2009 to 2013

    “What’s new about CMB-S4 is not the technology itself,” Borrill said, “but the scale at which we plan to deploy it – the sheer number of detectors, scale of the readout systems, number of telescopes, and volume of data to be processed.”

    Roe noted that Berkeley Lab has particular expertise in data management, and in the design and fabrication of detectors for CMB experiments.

    “This is a very big project,” Roe said. “We plan to staff up and bring in all of the expertise and capabilities from our sister labs and from the university community.”

    CMB-S4 will exceed the capabilities of earlier generations of experiments by more than 10 times. It will have the combined viewing power of three large and 18 small telescopes. The major technology challenge for CMB-S4 is in its scale. While previous generations of instruments have used tens of thousands of detectors, the entire CMB-S4 project will require half a million.

    The latest detector design, adapted from current experiments, will feature over 500 silicon wafers that each contain 1,000 superconducting detectors, on average – some wafers will contain up to 2,000 detectors.

    6
    This prototype wafer, measuring about 5 inches across, with over 1,000 detectors, was made to test detector fabrication processes and detector quality for the CMB-S4 experiment. (Photo courtesy of Aritoki Suzuki/Berkeley Lab)

    Aritoki Suzuki, a Berkeley Lab staff scientist, who is a detector team co-lead for CMB-S4, has been working with industry to develop faster and cheaper manufacturing processes for the detectors, as an option that can be considered, and noted that multiple manufacturing sites at research institutions are needed, too.

    “Delivering nearly 500,000 detectors will be one of the biggest challenges of the project,” Suzuki said. “We will combine forces from national labs, universities, and industry partners to tackle this immense task.”

    Another major hardware focus for the project will be the construction of new telescopes. The data-management challenges will be substantial, too, as these huge arrays of detectors will produce 1,000 times more data than the Planck satellite.

    CMB-S4 plans to draw upon computing resources at Berkeley Lab’s NERSC and the Argonne Leadership Computing Facility (ALCF), and to apply to NSF’s Open Science Grid and eXtreme Science and Engineering Discovery Environment (XSEDE).

    The project is hoping to deploy its first telescope in 2027, to be fully operational at all telescopes within a couple of years, and to run through 2035.

    Next steps include preparing a project office at Berkeley Lab, getting ready for the next DOE milestone, known as Critical Decision 1, working toward becoming an NSF project, and working across the community to bring in the best expertise and capabilities.

    ALCF and NERSC are DOE Office of Science user facilities.

    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, did most of the work on Dark Matter.

    Fritz Zwicky from http:// palomarskies.blogspot.com

    Coma cluster via NASA/ESA Hubble

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


    Vera Rubin, with Department of Terrestrial Magnetism (DTM) image tube spectrograph attached to the Kitt Peak 84-inch telescope, 1970. https://home.dtm.ciw.edu

    The Vera C. Rubin Observatory 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 existing Gemini South and Southern Astrophysical Research Telescopes.

    LSST Data Journey, Illustration by Sandbox Studio, Chicago with Ana Kova

    Dark Energy Survey


    Dark Energy Camera [DECam], built at FNAL


    NOAO/CTIO Victor M Blanco 4m Telescope which houses the DECam at Cerro Tololo, Chile, housing DECam at an altitude of 7200 feet

    Timeline of the Inflationary Universe WMAP

    The Dark Energy Survey (DES) 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. DES began searching the Southern skies on August 31, 2013.

    According to 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. 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.

    DES 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 DES 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.

    See the full article here .

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    LBNL campus

    LBNL Molecular Foundry

    Bringing Science Solutions to the World
    In the world of science, Lawrence Berkeley National Laboratory (Berkeley Lab) is synonymous with “excellence.” Thirteen Nobel prizes are associated with Berkeley Lab. Seventy Lab scientists are members of the National Academy of Sciences (NAS), one of the highest honors for a scientist in the United States. Thirteen of our scientists have won the National Medal of Science, our nation’s highest award for lifetime achievement in fields of scientific research. Eighteen of our engineers have been elected to the National Academy of Engineering, and three of our scientists have been elected into the Institute of Medicine. In addition, Berkeley Lab has trained thousands of university science and engineering students who are advancing technological innovations across the nation and around the world.

    Berkeley Lab is a member of the national laboratory system supported by the U.S. Department of Energy through its Office of Science. It is managed by the University of California (UC) and is charged with conducting unclassified research across a wide range of scientific disciplines. Located on a 202-acre site in the hills above the UC Berkeley campus that offers spectacular views of the San Francisco Bay, Berkeley Lab employs approximately 3,232 scientists, engineers and support staff. The Lab’s total costs for FY 2014 were $785 million. A recent study estimates the Laboratory’s overall economic impact through direct, indirect and induced spending on the nine counties that make up the San Francisco Bay Area to be nearly $700 million annually. The Lab was also responsible for creating 5,600 jobs locally and 12,000 nationally. The overall economic impact on the national economy is estimated at $1.6 billion a year. Technologies developed at Berkeley Lab have generated billions of dollars in revenues, and thousands of jobs. Savings as a result of Berkeley Lab developments in lighting and windows, and other energy-efficient technologies, have also been in the billions of dollars.

    Berkeley Lab was founded in 1931 by Ernest Orlando Lawrence, a UC Berkeley physicist who won the 1939 Nobel Prize in physics for his invention of the cyclotron, a circular particle accelerator that opened the door to high-energy physics. It was Lawrence’s belief that scientific research is best done through teams of individuals with different fields of expertise, working together. His teamwork concept is a Berkeley Lab legacy that continues today.

    A U.S. Department of Energy National Laboratory Operated by the University of California.

    University of California Seal

     
  • richardmitnick 11:00 am on May 15, 2020 Permalink | Reply
    Tags: "Seeing the Universe Through New Lenses", , , , , Dark Energy, , ,   

    From Lawrence Berkeley National Lab: “Seeing the Universe Through New Lenses” 


    From Lawrence Berkeley National Lab

    May 14, 2020
    Glenn Roberts Jr.
    (510) 520-0843
    geroberts@lbl.gov

    Images collected for dark energy telescope project reveal hundreds of new gravitational lens candidates.

    1
    This Hubble Space Telescope image shows a gravitational lens (center) that was first identified as a lens candidate with the assistance of a neural network that processed ground-based space images. The lens is artificially colorized and circled in this image. (Credit: Hubble Space Telescope)

    Like crystal balls for the universe’s deeper mysteries, galaxies and other massive space objects can serve as lenses to more distant objects and phenomena along the same path, bending light in revelatory ways.

    Gravitational lensing was first theorized by Albert Einstein more than 100 years ago to describe how light bends when it travels past massive objects like galaxies and galaxy clusters.

    These lensing effects are typically described as weak or strong, and the strength of a lens relates to an object’s position and mass and distance from the light source that is lensed. Strong lenses can have 100 billion times more mass than our sun, causing light from more distant objects in the same path to magnify and split, for example, into multiple images, or to appear as dramatic arcs or rings.

    The major limitation of strong gravitational lenses has been their scarcity, with only several hundred confirmed since the first observation in 1979, but that’s changing … and fast.

    A new study by an international team of scientists revealed 335 new strong lensing candidates based on a deep dive into data collected for a U.S. Department of Energy-supported telescope project in Arizona called the Dark Energy Spectroscopic Instrument (DESI).

    LBNL/DESI spectroscopic instrument on the Mayall 4-meter telescope at Kitt Peak National Observatory started in 2018

    NOAO/Mayall 4 m telescope at Kitt Peak, Arizona, USA, Altitude 2,120 m (6,960 ft)

    Kitt Peak National Observatory of the Quinlan Mountains in the Arizona-Sonoran Desert on the Tohono O’odham Nation, 88 kilometers 55 mi west-southwest of Tucson, Arizona, Altitude 2,096 m (6,877 ft)

    The study, published May 7 in The Astrophysical Journal, benefited from the winning machine-learning algorithm in an international science competition.

    “Finding these objects is like finding telescopes that are the size of a galaxy,” said David Schlegel, a senior scientist in Lawrence Berkeley National Laboratory’s (Berkeley Lab’s) Physics Division who participated in the study. “They’re powerful probes of dark matter and dark energy.”

    These newly discovered gravitational lens candidates could provide specific markers for precisely measuring distances to galaxies in the ancient universe if supernovae are observed and precisely tracked and measured via these lenses, for example.

    Strong lenses also provide a powerful window into the unseen universe of dark matter, which makes up about 85 percent of the matter in the universe, as most of the mass responsible for lensing effects is thought to be Dark Matter. Dark Matter and the accelerating expansion of the universe, driven by Dark Energy, are among the biggest mysteries that physicists are working to solve.

    In the latest study, researchers enlisted Cori, a supercomputer at Berkeley Lab’s National Energy Research Scientific Computing Center (NERSC), to automatically compare imaging data from the Dark Energy Camera Legacy Survey (DECaLS) – one of three surveys conducted in preparation for DESI – with a training sample of 423 known lenses and 9,451 non-lenses.

    NERSC Cray Cori II supercomputer at NERSC at LBNL, named after Gerty Cori, the first American woman to win a Nobel Prize in science

    The researchers grouped the candidate strong lenses into three categories based on the likelihood that they are, in fact, lenses: Grade A for the 60 candidates that are most likely to be lenses, Grade B for the 105 candidates with less pronounced features, and Grade C for the 176 candidate lenses that have fainter and smaller lensing features than those in the other two categories.

    Xiaosheng Huang, the study’s lead author, noted that the team already succeeded in winning time on the Hubble Space Telescope to confirm some of the most promising lensing candidates revealed in the study, with observing time on the Hubble that began in late 2019.

    “The Hubble Space Telescope can see the fine details without the blurring effects of Earth’s atmosphere,” Huang said.

    __________________________________________
    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, did most of the work on Dark Matter.

    Fritz Zwicky from http:// palomarskies.blogspot.com

    Coma cluster via NASA/ESA Hubble

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


    Vera Rubin, with Department of Terrestrial Magnetism (DTM) image tube spectrograph attached to the Kitt Peak 84-inch telescope, 1970. https://home.dtm.ciw.edu

    The Vera C. Rubin Observatory 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 existing Gemini South and Southern Astrophysical Research Telescopes.

    LSST Data Journey, Illustration by Sandbox Studio, Chicago with Ana Kova


    __________________________________________
    Dark Energy Survey


    Dark Energy Camera [DECam], built at FNAL


    NOAO/CTIO Victor M Blanco 4m Telescope which houses the DECam at Cerro Tololo, Chile, housing DECam at an altitude of 7200 feet

    Timeline of the Inflationary Universe WMAP

    The Dark Energy Survey (DES) 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. DES began searching the Southern skies on August 31, 2013.

    According to 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. 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.

    DES 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 DES 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.

    __________________________________________

    See the full article here .

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    LBNL campus

    LBNL Molecular Foundry

    Bringing Science Solutions to the World
    In the world of science, Lawrence Berkeley National Laboratory (Berkeley Lab) is synonymous with “excellence.” Thirteen Nobel prizes are associated with Berkeley Lab. Seventy Lab scientists are members of the National Academy of Sciences (NAS), one of the highest honors for a scientist in the United States. Thirteen of our scientists have won the National Medal of Science, our nation’s highest award for lifetime achievement in fields of scientific research. Eighteen of our engineers have been elected to the National Academy of Engineering, and three of our scientists have been elected into the Institute of Medicine. In addition, Berkeley Lab has trained thousands of university science and engineering students who are advancing technological innovations across the nation and around the world.

    Berkeley Lab is a member of the national laboratory system supported by the U.S. Department of Energy through its Office of Science. It is managed by the University of California (UC) and is charged with conducting unclassified research across a wide range of scientific disciplines. Located on a 202-acre site in the hills above the UC Berkeley campus that offers spectacular views of the San Francisco Bay, Berkeley Lab employs approximately 3,232 scientists, engineers and support staff. The Lab’s total costs for FY 2014 were $785 million. A recent study estimates the Laboratory’s overall economic impact through direct, indirect and induced spending on the nine counties that make up the San Francisco Bay Area to be nearly $700 million annually. The Lab was also responsible for creating 5,600 jobs locally and 12,000 nationally. The overall economic impact on the national economy is estimated at $1.6 billion a year. Technologies developed at Berkeley Lab have generated billions of dollars in revenues, and thousands of jobs. Savings as a result of Berkeley Lab developments in lighting and windows, and other energy-efficient technologies, have also been in the billions of dollars.

    Berkeley Lab was founded in 1931 by Ernest Orlando Lawrence, a UC Berkeley physicist who won the 1939 Nobel Prize in physics for his invention of the cyclotron, a circular particle accelerator that opened the door to high-energy physics. It was Lawrence’s belief that scientific research is best done through teams of individuals with different fields of expertise, working together. His teamwork concept is a Berkeley Lab legacy that continues today.

    A U.S. Department of Energy National Laboratory Operated by the University of California.

    University of California Seal

     
    • Barbarina Zwicky 6:10 pm on May 15, 2020 Permalink | Reply

      Rubin has been a constant nuisance to my father’s legacy in regard to Dark Matter and often took false credit for its discovery, crowning herself as “Discoverer of Dark Matter.” The naming of LSST after Rubin, is an undeserved honor for this celebrated plagiarist.

      Vera Rubin was celebrated in the press and by several institutions for her work in specific in regard to Dark Matter, my father’s discovery, as well as responsible for the roughshod over my father, his memory, and credit for his original work, by falsely assigning that credit to herself in numerous incidents involving the media and even nomenclature of her lecture: “I left Vassar and Found Dark Matter.” I consider Vera Rubin a person who attached herself to my father’s original work in parasitic forced credit, repeatedly advanced this unethical agenda and academic dishonesty, crowning herself as “Discoverer of Dark Matter,” the published achievement of another. Rubin’s dictates of conscience revealed a failed ethical compass as she assigned herself credit for my father’s methodology and that of others in the sciences in regard to the mathematical calculations in regard to the rotational speeds of galaxies, as well as claiming to be the “Discoverer of Dark Matter.” Vera Rubin was a constant unwanted barnacle that was attached to my father’s discovery, Dark Matter. The advancement of bringing the gravitational phenomena of Dark Matter to light and into the modern consciousness of physicists worldwide would have regardless been unsealed from the echoes of my father’s original work in 1933. Fritz Zwicky: “I consequently engaged in the application of certain simple general principles of morphological research, and in particular the method of Directed Intuition that would allow me to predict and visualize the existence of as yet unknown cosmic objects and phenomena.” Fritz Zwicky’s eidolon was realized from the results of his observations published in “Die Rotverschiebung von extragalaktischen Nebeln”, Helv. Phys. Acta 6, 110-127 (1933). English translation Johannes Nicolai Meyling – Barbarina Exita Zwicky (2013). Fritz Zwicky discovered Dark Matter and coined, dunkle (kalte) Materie (cold dark matter) in his 1933 article referenced above. The Mass-Radial Acceleration Discrepancy by measuring the speeds of galaxies in the Coma Cluster originated with Fritz Zwicky, not Rubin, as using the more challenging methodology of the virial theorem, by relating the total average kinetic energy and the total average potential energy of the galaxies of the Coma Cluster. He advanced that the virial for a pair of orbiting masses is zero, and used the principle of superposition to craft the argument to a system of interacting mass points. Zwicky then used the position and velocity measurements to determine the mass of the galaxy cluster. The LSST will endeavor to discover Dark Matter and should not be renamed at all, and certainly not after Vera Rubin, who plagiarized discovery in regard to Dark Matter, without acknowledgment of its provenance and pioneer, Fritz Zwicky, and deprives rightful illumination to the Father of Dark Matter. It will highlight this interloper and celebrate this forced credit from the rightful person due, Fritz Zwicky, by memorializing the name of LSST after this faux “pioneer” and self-proclaimed “Discoverer of Dark Matter.”

      Like

  • richardmitnick 12:14 pm on April 23, 2020 Permalink | Reply
    Tags: "Detailed Cosmic Map to Reveal Dark Energy's Sway", , , , , Dark Energy, , ,   

    From The Kavli Foundation: “Detailed Cosmic Map to Reveal Dark Energy’s Sway” 

    KavliFoundation

    From The Kavli Foundation

    03/25/2020 [Just now in social media.]

    Media Contact

    Katie McKissick
    The Kavli Foundation
    (424) 353-8800
    kmckissick@kavlifoundation.org

    By Adam Hadhazy

    LBNL/DESI spectroscopic instrument on the Mayall 4-meter telescope at Kitt Peak National Observatory started in 2018

    .

    3
    DESI, a bold celestial mapmaking effort, will help unravel the mystery of the universe’s accelerating expansion rate. Here, star trails take shape around the 14-story Mayall Telescope dome in this long-exposure image. The Dark Energy Spectroscopic Instrument resides within this dome. (Credit: P. Marenfeld and NOAO/AURA/NSF)​

    NOAO/Mayall 4 m telescope at Kitt Peak, Arizona, USA, Altitude 2,120 m (6,960 ft)

    Kitt Peak National Observatory of the Quinlan Mountains in the Arizona-Sonoran Desert on the Tohono O’odham Nation, 88 kilometers 55 mi west-southwest of Tucson, Arizona, Altitude 2,096 m (6,877 ft)

    Compared to cosmic mapmakers, terrestrial cartographers have it relatively easy. Map generation here on Earth generally deals with just two dimensions—the latitude and longitude of where portions of landmasses and oceans all stitch together, forming the surface of our planet.

    Out in space, though, the third dimension reigns.

    After all, space is not called “space” for nothing; the sheer amount of volume out there through which galaxies are strewn is staggering. In order to understand the universe’s development, researchers need to chart its great expanse by accurately gauging distances between clusters of galaxies. Like on Earth, where the location of landmasses today speaks to eons of geophysical evolution, continental drift, tectonics, and so on, so, too, do the locations of galaxies speak to the dynamic history of the cosmos.

    The geo-analogy is only so apt, however, because looking deep into space is also looking deep into time; the farther away something is, the farther back in the universe’s chronology we are glimpsing it. As a result, not only does a cosmic map capture where things are in relation to each other, it also captures when things are in relation to each other.

    Tackling this time-and-space challenge anew is the Dark Energy Spectroscopic Instrument (DESI). Now mounted on a telescope in Arizona, DESI will soon begin making the most detailed 3D map of the universe to date. More than 500 researchers, hailing from 75 institutions in 13 countries, are part of the DESI project, including researchers at the Kavli Institute for Particle Astrophysics and Cosmology (KIPAC), a joint project of Stanford University and the SLAC National Accelerator Laboratory.




    Numbers-wise, over a five-year observing run that starts in 2020, DESI will look at a third of the sky, accurately mapping the distances to approximately 35 million galaxies and 2.4 million quasars. (Quasars are ultra-bright galaxies whose central supermassive black holes are gorging on matter.) That tidy galactic sum represents about 20 times more objects than any previous such effort.

    “We’ll know in 3D space where the galaxies are with DESI, and with that, we can look at how galaxies are arranged in the universe,” says Aaron Roodman, who worked on image analysis elements of the Guiding, Focusing and Alignment (GFA) subsystem for DESI. Roodman is a professor and chair of the Particle Physics & Astrophysics department at SLAC and a member of KIPAC.

    DESI’s mapmaking is not for astronaut traveling purposes, of course. (Heck, we humans will be lucky if we get back to the Moon in the next decade, after a 50-year hiatus.) Instead, the goal for DESI is to help us better understand the history and eventual fate of the universe by nailing down the workings of Dark Energy. Right there in DESI’s name, “dark energy” refers to an enigmatic force that theoretically comprises most of reality.

    “This thing we call dark energy makes up 70 of the matter-energy density of the universe, but we don’t know what it is,” says Roodman.

    Dark energy’s presence looms large, invoked to explain why the universe’s rate of acceleration is increasing over history. The overall situation is thus: Matter, the substance that comprises everything we deal with every day, registers at just 5% of the total contents of the cosmos. A second enigmatic ingredient, Dark Matter, takes up the remaining 25% percent (once dark energy’s dominance – clocking in at nearly 70% – is counted). Dark matter interacts with normal matter only through gravity, so far as we know, acting like a universe-spanning scaffold upon which normal matter is hung. That normal matter interacts with itself through the forces of nature to give us galaxies, stars, planets, elephants, paramecia, you name it.

    Researchers want to bring this overview picture into sharper focus. “With DESI, we will be able to independently measure the universe’s expansion rate and how fast its structure of matter and dark matter grow, both of which are influenced by dark energy. Then when you compare those measurements, you get a precise test of the physics governing the universe,” said Risa Wechsler, the current Director of KIPAC and former spokesperson of the DESI collaboration, in comments to The Kavli Foundation in 2017.

    The other part of DESI’s name, “spectroscopic,” refers to how DESI will get the all-important distance measurements to millions of galaxies. DESI contains 5,000 robotic “eyes,” made of human-hair-thin, cosmic-light-gathering fiber optic cables, held in particular orientations by robotic positioners. Each “eye” is pointed at a bright galaxy to collect enough of its stars’ collective light to perform spectroscopy—breaking apart the light into different wavelengths for study. “Whatever light comes down the fiber, we spread out the whole rainbow,” says Roodman. The signature astronomers look for in this light is called redshift, caused by the universe’s expansion, and which can be used to determine a galaxy’s distance.

    With precise distance measurements to an unprecedentedly large swath of galaxies, the DESI researchers will plot the course of dark energy’s influence as never before, better constraining its properties. Roodman, for one, can’t wait.

    “What is causing the expansion of the universe to accelerate is a question I’m very interested in,” says Roodman. “DESI will really teach us something about dark energy.”

    __________________________________________________
    Dark Energy Survey


    Dark Energy Camera [DECam], built at FNAL


    NOAO/CTIO Victor M Blanco 4m Telescope which houses the DECam at Cerro Tololo, Chile, housing DECam at an altitude of 7200 feet

    Timeline of the Inflationary Universe WMAP

    The Dark Energy Survey (DES) 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. DES began searching the Southern skies on August 31, 2013.

    According to 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. 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.
    __________________________________________________
    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, did most of the work on Dark Matter.

    Fritz Zwicky from http:// palomarskies.blogspot.com

    Coma cluster via NASA/ESA Hubble

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


    Vera Rubin, with Department of Terrestrial Magnetism (DTM) image tube spectrograph attached to the Kitt Peak 84-inch telescope, 1970. https://home.dtm.ciw.edu

    The Vera C. Rubin Observatory 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 existing Gemini South and Southern Astrophysical Research Telescopes.

    LSST Data Journey, Illustration by Sandbox Studio, Chicago with Ana Kova

    __________________________________________________

    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 Kavli Foundation, based in Oxnard, California, is dedicated to the goals of advancing science for the benefit of humanity and promoting increased public understanding and support for scientists and their work.

    The Foundation’s mission is implemented through an international program of research institutes, professorships, and symposia in the fields of astrophysics, nanoscience, neuroscience, and theoretical physics as well as prizes in the fields of astrophysics, nanoscience, and neuroscience.

     
  • richardmitnick 11:53 am on February 23, 2020 Permalink | Reply
    Tags: , , , , Dark Energy, , , , , , ,   

    From EarthSky: “What is dark matter?” 

    1

    From EarthSky

    February 23, 2020
    Andy Briggs

    Dark Matter doesn’t emit light. It can’t be directly observed with any of the existing tools of astronomers. Yet astrophysicists believe it and Dark Energy make up most of the mass of the cosmos. What dark matter is, and what it isn’t. here.

    1
    Since the 1930s, astrophysicists have been trying to explain why the visible material in galaxies can’t account for how galaxies are shaped, or how they behave. They believe a form of dark or invisible matter pervades our universe, but they still don’t know what this dark matter might be. Image via ScienceAlert.

    Dark matter is a mysterious substance thought to compose perhaps about 27% of the makeup of the universe. What is it? It’s a bit easier to say what it isn’t.

    It isn’t ordinary atoms – the building blocks of our own bodies and all we see around us – because atoms make up only somewhere around 5% of the universe, according to a cosmological model called the Lambda Cold Dark Matter Model (aka the Lambda-CDM model, or sometimes just the Standard Model).

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

    Dark Matter isn’t the same thing as Dark Energy, which makes up some 68% of the universe, according to the Standard Model.

    Dark Energy Survey


    Dark Energy Camera [DECam], built at FNAL


    NOAO/CTIO Victor M Blanco 4m Telescope which houses the DECam at Cerro Tololo, Chile, housing DECam at an altitude of 7200 feet

    Timeline of the Inflationary Universe WMAP

    The Dark Energy Survey (DES) 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. DES began searching the Southern skies on August 31, 2013.

    According to 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. 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.

    DES 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 DES 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 is invisible; it doesn’t emit, reflect or absorb light or any type of electromagnetic radiation such as X-rays or radio waves. Thus, dark matter is undetectable directly, as all of our observations of the universe, apart from the detection of gravitational waves, involve capturing electromagnetic radiation in our telescopes.

    Gravitational waves Werner Benger-ZIB-AEI-CCT-LSU

    Yet dark matter does interact with ordinary matter. It exhibits measurable gravitational effects on large structures in the universe such as galaxies and galaxy clusters. Because of this, astronomers are able to make maps of the distribution of dark matter in the universe, even though they cannot see it directly.

    They do this by measuring the effect dark matter has on ordinary matter, through gravity.

    2
    This all-sky image – released in 2013 – shows the distribution of dark matter across the entire history of the universe as seen projected on the sky. It’s based on data collected with the European Space Agency’s Planck satellite.

    ESA/Planck 2009 to 2013

    Dark blue areas represent regions that are denser than their surroundings. Bright areas represent less dense regions. The gray portions of the image correspond to patches of the sky where foreground emission, mainly from the Milky Way but also from nearby galaxies, prevents cosmologists from seeing clearly. Image via ESA.

    There is currently a huge international effort to identify the nature of dark matter. Bringing an armory of advanced technology to bear on the problem, astronomers have designed ever-more complex and sensitive detectors to tease out the identity of this mysterious substance.

    Dark Matter Research

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

    Scientists studying the cosmic microwave background hope to learn about more than just how the universe grew—it could also offer insight into dark matter, dark energy and the mass of the neutrino.

    Dark matter cosmic web and the large-scale structure it forms The Millenium Simulation, V. Springel et al

    Dark Matter Particle Explorer China

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

    LBNL LZ Dark Matter project at SURF, Lead, SD, USA


    Inside the ADMX experiment hall at the University of Washington Credit Mark Stone U. of Washington. Axion Dark Matter Experiment

    Dark matter might consist of an as yet unidentified subatomic particle of a type completely different from what scientists call baryonic matter – that’s just ordinary matter, the stuff we see all around us – which is made of ordinary atoms built of protons and neutrons.

    The list of candidate subatomic particles breaks down into a few groups: there are the WIMPs (Weakly Interacting Massive Particles), a class of particles thought to have been produced in the early universe. Astronomers believe that WIMPs might self-annihilate when colliding with each other, so they have searched the skies for telltale traces of events such as the release of neutrinos or gamma rays. So far, they’ve found nothing. In addition, although a theory called supersymmetry predicts the existence of particles with the same properties as WIMPs, repeated searches to find the particles directly have also found nothing, and experiments at the Large Hadron Collider to detect the expected presence of supersymmetry have completely failed to find it.

    Standard Model of Supersymmetry via DESY

    CERN/LHC Map


    CERN LHC Maximilien Brice and Julien Marius Ordan


    SixTRack CERN LHC particles

    Several different types of detector have been used to detect WIMPs. The general idea is that very occasionally, a WIMP might collide with an ordinary atom and release a faint flash of light, which can be detected. The most sensitive detector built to date is XENON1T, which consists of a 10-meter cylinder containing 3.2 tons of liquid xenon, surrounded by photomultipliers to detect and amplify the incredibly faint flashes from these rare interactions. As of July 2019, when the detector was decommissioned to pave the way for a more sensitive instrument, the XENONnT, no collisions between WIMPs and the xenon atoms had been seen.

    XENON1T at Gran Sasso LABORATORI NAZIONALI del GRAN SASSO, located in the Abruzzo region of central Italy


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

    At the moment, a hypothetical particle called the Axion is receiving much attention.

    CERN CAST Axion Solar Telescope

    As well as being a strong candidate for dark matter, the existence of axions is also thought to provide the answers to a few other persistent questions in physics such as the Strong CP Problem.

    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, did most of the work on Dark Matter.

    Fritz Zwicky from http:// palomarskies.blogspot.com

    Coma cluster via NASA/ESA Hubble

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


    Vera Rubin, with Department of Terrestrial Magnetism (DTM) image tube spectrograph attached to the Kitt Peak 84-inch telescope, 1970. https://home.dtm.ciw.edu

    The Vera C. Rubin Observatory 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 existing Gemini South and Southern Astrophysical Research Telescopes.

    LSST Data Journey, Illustration by Sandbox Studio, Chicago with Ana Kova

    Some astronomers have tried to negate the need the existence of dark matter altogether by postulating something called Modified Newtonian dynamics (MOND).

    Mordehai Milgrom, MOND theorist, is an Israeli physicist and professor in the department of Condensed Matter Physics at the Weizmann Institute in Rehovot, Israel http://cosmos.nautil.us

    MOND Modified Newtonian Dynamics a Humble Introduction Marcus Nielbock

    The idea behind this is that gravity behaves differently over long distances to what it does locally, and this difference of behavior explains phenomena such as galaxy rotation curves which we attribute to dark matter. Although MOND has its supporters, while it can account for the rotation curve of an individual galaxy, current versions of MOND simply cannot account for the behavior and movement of matter in large structures such as galaxy clusters and, in its current form, is thought unable to completely account for the existence of dark matter. That is to say, gravity does behave in the same way at all scales of distance. Most versions of MOND, on the other hand, have two versions of gravity, the weaker one occurring in regions of low mass concentration such as in the outskirts of galaxies. However, it is not inconceivable that some new version of MOND in the future might yet account for dark matter.

    Although some astronomers believe we will establish the nature of dark matter in the near future, the search so far has proved fruitless, and we know that the universe often springs surprises on us so that nothing can be taken for granted.

    The approach astronomers are taking is to eliminate those particles which cannot be dark matter, in the hope we will be left with the one which is.

    It remains to be seen if this approach is the correct one.

    See the full article here .


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

    Stem Education Coalition

    Deborah Byrd created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. “Being an EarthSky editor is like hosting a big global party for cool nature-lovers,” she says.

     
c
Compose new post
j
Next post/Next comment
k
Previous post/Previous comment
r
Reply
e
Edit
o
Show/Hide comments
t
Go to top
l
Go to login
h
Show/Hide help
shift + esc
Cancel
%d bloggers like this: