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  • richardmitnick 10:42 am on June 14, 2019 Permalink | Reply
    Tags: Astromomy Magazine, , , , CMB - Cosmic Microwave Background,   

    From Astronomy Magazine: “The mystery of cosmic cold spots just got even weirder” 

    Astronomy magazine

    From Astronomy Magazine

    June 06, 2019
    Korey Haynes

    Recent analysis of Planck data upholds mysteries that have existed since the spacecraft’s first results in 2013. ESA/Planck Collaboration

    During its time in orbit, the European Space Agency’s Planck spacecraft gave humanity the most sophisticated measurements ever made of the cosmic microwave background (CMB) radiation, the first flash of light that rippled across the universe after the Big Bang. Plank told us the shape of the universe and confirmed crucial components of the Big Bang as it collected data between 2009 and 2013. It did all that by measuring the intensity of the CMB across the sky. And since then astronomers have kept putting out new maps of the cosmos as they mine data and discover new ways to tease out secrets.

    While Planck’s measurements in large part confirmed physicists’ understanding of the universe, some of the most interesting things Planck discovered were the unexpected details. For one, the universe seems divided into two hemispheres, one hot and one cold. And the hot hemisphere also contains a stark cold spot. Neither of these details were predicted, and shouldn’t in fact exist, according to the so-called standard cosmological model, which otherwise well describes the universe as viewed by Planck. The third surprise is the very slight way Planck’s measurements stray from the standard model, only at large scales. While earlier spacecraft had hinted at all these issues, Planck confirmed them for scientists, bringing into high resolution a problem many researchers had hoped would instead fade away with increased precision.

    Now, scientists have compared Planck’s map of those temperature anomalies – where space itself is just slightly warmer or cooler than the average of just above absolute zero – to a map of the sky’s polarization. This second map holds a record of how the light scattered across the sky just 380,000 years after the Big Bang. Researchers hoped the polarization map could answer questions about the meaning of the anomalies they’d been watching in the temperature maps by either strongly echoing them or not showing them at all. But the polarization map shows either no or faint evidence of the anomalies, leaving scientists still wondering – are the signals saying something important about the makeup of our universe? Or are they merely random fluctuations in space, signifying nothing at all?

    Mapping cosmic differences

    In the temperature maps, researchers had noted suspicious anomalies that show up at large scales – some 10 times bigger than the full Moon on the sky. These temperature variations don’t match with standard explanations of the universe’s physics as we know it. Scientists have also proven that the features are not due to observing quirks of their telescope. They are, however, just faint enough that these cold spots could possibly be random – while also being just strong enough that scientists can’t quite ignore them.

    Their appearance hints that something about the standard cosmological model isn’t quite right.

    Because the polarization map is a largely independent measurement of the sky (though taken with the same spacecraft), scientists hoped it could shed light on whether the anomalies were a true signal of something previously unknown about the universe, or simply a random fluctuation.

    Unfortunately, when they compared the most advanced maps that Planck has produced, they found only faint evidence of the anomalies. That is, the spots appear, but not in a statistically significant way. Researchers from across the Planck Collaboration published their results in the journal Astronomy and Astrophysics on Thursday.

    This leaves scientists stuck with two possibilities. The first is that the anomalies are simply flukes of statistics – stronger than suggested by physics, but still just random, the way coin flips don’t always turn up exactly 50/50, even after 1,000 tries.

    The other possibility is some kind of new physics not currently explained by the standard model. That option is less likely now, given the polarization maps didn’t show the anomalies very clearly. But they do show faint signs of the signals, and because scientists don’t know what this new physics might be, there’s no way for them to know if it should show up in both polarization and temperature maps.

    The anomalies in the cosmic microwave background have been, and remain, a thorn in the side of the standard cosmological model. The standard model encompasses the area in green, while Planck’s data appears as red points with error bars. For small scales (the right side of the graph) the two match quite well, while there is less agreement – but also more uncertainty – at large scales. ESA/Planck Collaboration

    Planck isn’t taking new data, and scientists have probably produced the most detailed maps they can from the available information. While clever ideas might yet emerge, solving this mystery with new information will likely have to wait another decade or more, until a new generation of CMB-spying spacecraft take to the skies.

    See the full article here .


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  • richardmitnick 8:43 am on May 9, 2019 Permalink | Reply
    Tags: "A New Filter to Better Map the Dark Universe", , , “Lensing can magnify or demagnify things. It also distorts them along a certain axis so they are stretched in one direction.”, , CMB - Cosmic Microwave Background, , , , The researchers found that a certain lensing signature called shearing seems largely immune to the foreground “noise” effects that otherwise interfere with the CMB lensing data.,   

    From Lawrence Berkeley National Lab: “A New Filter to Better Map the Dark Universe” 

    Berkeley Logo

    From Lawrence Berkeley National Lab

    May 8, 2019
    Glenn Roberts Jr.
    (510) 486-5582

    Just as a wine glass distorts an image, showing temperature fluctuations in the cosmic microwave background [CMB] in this photo illustration, large objects like galaxy clusters and galaxies can similarly distort this light to produce lensing effects. (Credit: Emmanuel Schaan and Simone Ferraro/Berkeley Lab)

    The earliest known light in our universe, known as the cosmic microwave background [CMB], was emitted about 380,000 years after the Big Bang.

    CMB per ESA/Planck

    ESA/Planck 2009 to 2013

    The patterning of this relic light holds many important clues to the development and distribution of large-scale structures such as galaxies and galaxy clusters.

    Gravitational Lensing NASA/ESA

    Distortions in the cosmic microwave background (CMB), caused by a phenomenon known as lensing, can further illuminate the structure of the universe and can even tell us things about the mysterious, unseen universe – including dark energy, which makes up about 68 percent of the universe and accounts for its accelerating expansion, and dark matter, which accounts for about 27 percent of the universe.

    Set a stemmed wine glass on a surface, and you can see how lensing effects can simultaneously magnify, squeeze, and stretch the view of the surface beneath it. In lensing of the CMB, gravity effects from large objects like galaxies and galaxy clusters bend the CMB light in different ways. These lensing effects can be subtle (known as weak lensing) for distant and small galaxies, and computer programs can identify them because they disrupt the regular CMB patterning.

    Weak gravitational lensing NASA/ESA Hubble

    There are some known issues with the accuracy of lensing measurements, though, and particularly with temperature-based measurements of the CMB and associated lensing effects.

    While lensing can be a powerful tool for studying the invisible universe, and could even potentially help us sort out the properties of ghostly subatomic particles like neutrinos, the universe is an inherently messy place.

    And like bugs on a car’s windshield during a long drive, the gas and dust swirling in other galaxies, among other factors, can obscure our view and lead to faulty readings of the CMB lensing.

    There are some filtering tools that help researchers to limit or mask some of these effects, but these known obstructions continue to be a major problem in the many studies that rely on temperature-based measurements.

    The effects of this interference with temperature-based CMB studies can lead to erroneous lensing measurements, said Emmanuel Schaan, a postdoctoral researcher and Owen Chamberlain Postdoctoral Fellow in the Physics Division at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab).

    “You can be wrong and not know it,” Schaan said. “The existing methods don’t work perfectly – they are really limiting.”

    To address this problem, Schaan teamed up with Simone Ferraro, a Divisional Fellow in Berkeley Lab’s Physics Division, to develop a way to improve the clarity and accuracy of CMB lensing measurements by separately accounting for different types of lensing effects.

    “Lensing can magnify or demagnify things. It also distorts them along a certain axis so they are stretched in one direction,” Schaan said.

    The researchers found that a certain lensing signature called shearing, which causes this stretching in one direction, seems largely immune to the foreground “noise” effects that otherwise interfere with the CMB lensing data. The lensing effect known as magnification, meanwhile, is prone to errors introduced by foreground noise. Their study, published May 8 in the journal Physical Review Letters, notes a “dramatic reduction” in this error margin when focusing solely on shearing effects.

    A set of cosmic microwave background images with no lensing effects (top row) and with exaggerated cosmic microwave background lensing effects (bottom row). (Credit: Wayne Hu and Takemi Okamoto/University of Chicago)

    The sources of the lensing, which are large objects that stand between us and the CMB light, are typically galaxy groups and clusters that have a roughly spherical profile in temperature maps, Ferraro noted, and the latest study found that the emission of various forms of light from these “foreground” objects only appears to mimic the magnification effects in lensing but not the shear effects.

    “So we said, ‘Let’s rely only on the shear and we’ll be immune to foreground effects,’” Ferraro said. “When you have many of these galaxies that are mostly spherical, and you average them, they only contaminate the magnification part of the measurement. For shear, all of the errors are basically gone.”

    He added, “It reduces the noise, allowing us to get better maps. And we’re more certain that these maps are correct,” even when the measurements involve very distant galaxies as foreground lensing objects.

    The new method could benefit a range of sky-surveying experiments, the study notes, including the POLARBEAR-2 and Simons Array experiments, which have Berkeley Lab and UC Berkeley participants; the Advanced Atacama Cosmology Telescope (AdvACT) project; and the South Pole Telescope – 3G camera (SPT-3G). It could also aid the Simons Observatory and the proposed next-generation, multilocation CMB experiment known as CMB-S4 – Berkeley Lab scientists are involved in the planning for both of these efforts.

    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.

    LBL The Simons Array in the Atacama in Chile, with the 6 meter Atacama Cosmology Telescope

    South Pole Telescope SPTPOL. The SPT collaboration is made up of over a dozen (mostly North American) institutions, including the University of Chicago, the University of California, Berkeley, Case Western Reserve University, Harvard/Smithsonian Astrophysical Observatory, the University of Colorado Boulder, McGill University, The University of Illinois at Urbana-Champaign, University of California, Davis, Ludwig Maximilian University of Munich, Argonne National Laboratory, and the National Institute for Standards and Technology. It is funded by the National Science Foundation.

    South Pole Telescope SPT-3G Camera

    The method could also enhance the science yield from future galaxy surveys like the Berkeley Lab-led Dark Energy Spectroscopic Instrument (DESI) project under construction near Tucson, Arizona, and the Large Synoptic Survey Telescope (LSST) project under construction in Chile, through joint analyses of data from these sky surveys and the CMB lensing data.

    LBNL/DESI spectroscopic instrument on the Mayall 4-meter telescope at Kitt Peak National Observatory starting 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)


    LSST Camera, built at SLAC

    LSST telescope, currently under construction on the El Peñón peak at Cerro Pachón Chile, a 2,682-meter-high mountain in Coquimbo Region, in northern Chile, alongside the existing Gemini South and Southern Astrophysical Research Telescopes.

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

    Increasingly large datasets from astrophysics experiments have led to more coordination in comparing data across experiments to provide more meaningful results. “These days, the synergies between CMB and galaxy surveys are a big deal,” Ferraro said.

    These images show different types of emissions that can interfere with CMB lensing measurements, as simulated by Neelima Sehgal and collaborators. From left to right: The cosmic infrared background, composed of intergalactic dust; radio point sources, or radio emission from other galaxies; the kinematic Sunyaev-Zel’dovich effect, a product of gas in other galaxies; and the thermal Sunyaev-Zel’dovich effect, which also relates to gas in other galaxies. (Credit: Emmanuel Schaan and Simone Ferraro/Berkeley Lab)

    In this study, researchers relied on simulated full-sky CMB data. They used resources at Berkeley Lab’s National Energy Research Scientific Computing Center (NERSC) to test their method on each of the four different foreground sources of noise, which include infrared, radiofrequency, thermal, and electron-interaction effects that can contaminate CMB lensing measurements.


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

    NERSC Hopper Cray XE6 supercomputer

    LBL NERSC Cray XC30 Edison supercomputer

    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.


    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.


    Cray Shasta Perlmutter SC18 AMD Epyc Nvidia pre-exascale supeercomputer

    The study notes that cosmic infrared background noise, and noise from the interaction of CMB light particles (photons) with high-energy electrons have been the most problematic sources to address using standard filtering tools in CMB measurements. Some existing and future CMB experiments seek to lessen these effects by taking precise measurements of the polarization, or orientation, of the CMB light signature rather than its temperature.

    “We couldn’t have done this project without a computing cluster like NERSC,” Schaan said. NERSC has also proved useful in serving up other universe simulations to help prepare for upcoming experiments like DESI (see related article).

    The method developed by Schaan and Ferraro is already being implemented in the analysis of current experiments’ data. One possible application is to develop more detailed visualizations of dark matter filaments and nodes that appear to connect matter in the universe via a complex and changing cosmic web.

    The researchers reported a positive reception to their newly introduced method.

    “This was an outstanding problem that many people had thought about,” Ferraro said. “We’re happy to find elegant solutions.”

    NERSC is a DOE Office of Science User Facility.

    See the full article here .


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    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

    DOE Seal

  • richardmitnick 11:18 am on May 7, 2019 Permalink | Reply
    Tags: "A universe is born", , , , CMB - Cosmic Microwave Background, , , , , , , , , The Planck epoch   

    From Symmetry: “A universe is born” 

    Symmetry Mag
    From Symmetry

    Diana Kwon

    Take a (brief) journey through the early history of our cosmos.

    Timeline of the Inflationary Universe WMAP

    The universe was a busy place during the first three minutes. The cosmos we see today expanded from a tiny speck to much closer to its current massive size; the elementary particles appeared; and protons and neutrons combined into the first nuclei, filling the universe with the precursors of elements.

    By developing clever theories and conducting experiments with particle colliders, telescopes and satellites, physicists have been able to wind the film of the universe back billions of years—and glimpse the details of the very first moments in the history of our cosmic home.

    Take an abridged tour through this history:

    The Planck epoch
    Time: < 10^-43 seconds

    The Planck Epoch https:// http://www.slideshare.net ericgolob the-big-bang-10535251

    Welcome to the Planck epoch, named after the smallest scale of measurements possible in particle physics today. This is currently the closet scientists can get to the beginning of time.

    Theoretical physicists don’t know much about the earliest moments of the universe. After the Big Bang theory gained popularity, scientists thought that in the first moments, the cosmos was at its hottest and densest and that all four fundamental forces—electromagnetic, weak, strong and gravitational—were combined into a single, unified force. But the current leading theoretical framework for our universe’s beginning doesn’t necessarily require these conditions.

    The universe expands
    Time: From 10^-43 seconds to about 10^-36 seconds

    In this stage, which began either at Planck time or shortly after it, scientists think the universe underwent superfast, exponential expansion in a process known as inflation.


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

    HPHS Owls

    Lambda-Cold Dark Matter, Accelerated Expansion of the Universe, Big Bang-Inflation (timeline of the universe) Date 2010 Credit: Alex MittelmannColdcreation

    Alan Guth’s notes:

    Physicists first proposed the theory of inflation in the 1980s to address the shortcomings of the Big Bang theory, which, despite its popularity, could not explain why the universe was so flat and uniform, and why its different parts began expanding simultaneously.

    During inflation, quantum fluctuations could have stretched out to produce a pattern that later determined the locations of galaxies. It might have been only after this period of inflation the universe became a hot, dense fireball as described in the Big Bang theory.

    The elementary particles are born
    Time: ~10^-36 seconds

    When the universe was still very hot, the cosmos was like a gigantic accelerator, much more powerful than the Large Hadron Collider, running at extremely high energies. In it, the elementary particles we know today were born.

    Scientists think that first came exotic particles, followed by more familiar ones, such as electrons, neutrinos and quarks. It could be that dark matter particles came about during this time.

    Quarks APS/Alan Stonebraker

    The quarks soon combined, forming the familiar protons and neutrons, which are collectively known as baryons. Neutrinos were able to escape this plasma of charged particles and began traveling freely through space, while photons continued to be trapped by the plasma.

    Standard Model of Particle Physics

    The first nuclei emerge
    Time: ~1 second to 3 minutes

    Scientists think that when the universe cooled enough for violent collisions to subside, protons and neutrons clumped together into nuclei of the light elements—hydrogen, helium and lithium—in a process known as Big Bang nucleosynthesis.

    Protons are more stable than neutrons, due to their lower mass. In fact, a free neutron decays with a 15-minute half-life, while protons may not decay at all, as far as we know.

    So as the particles combined, many protons remained unpaired. As a result, hydrogen—protons that never found a partner—make up around 74% of the mass of “normal” matter in our cosmos. The second most abundant element is helium, which makes up approximately 24%, followed by trace amounts of deuterium, lithium, and helium-3 (helium with a three-baryon core).

    Periodic table Sept 2017. Wikipedia

    Scientists have been able to accurately measure the density of baryons in our universe. Most of those measurements line up with theorists’ estimations of what the quantities ought to be, but there is one lingering issue: Lithium calculations are off by a factor of three. It could be that the measurements are off, but it could also be that something we don’t yet know about happened during this time period to change the abundance of lithium.

    The cosmic microwave background becomes visible
    Time: 380,000 years

    Hundreds of thousands of years after inflation, the particle soup had cooled enough for electrons to bind to nuclei to form electrically neutral atoms. Through this process, which is also known as recombination, photons became free to traverse the universe, creating the cosmic microwave background.

    CMB per ESA/Planck

    ESA/Planck 2009 to 2013

    Today, the CMB is one of the most valuable tools for cosmologists, who probe its depths in search of answers for many of the universe’s lingering secrets, including the nature of inflation and the cause of matter-antimatter asymmetry.

    Shortly after the CMB became detectable, neutral hydrogen particles formed into a gas that filled the universe. Without any objects emitting high-energy photons, the cosmos was plunged into the dark ages for millions of years.

    Dark Energy Camera Enables Astronomers a Glimpse at the Cosmic Dawn. CREDIT National Astronomical Observatory of Japan

    The earliest stars shine
    Time: ~100 million years

    The dark ages ended with the formation of the first stars and the occurrence of reionization, a process through which highly energetic photons stripped electrons off neutral hydrogen atoms.

    Reionization era and first stars, Caltech

    Scientists think that the vast majority of the ionizing photons emerged from the earliest stars. But other processes, such as collisions between dark matter particles, may have also played a role.

    At this time, matter began to form the first galaxies. Our own galaxy, the Milky Way, contains stars that were born when the universe was only several hundred million years old.

    Milky Way NASA/JPL-Caltech /ESO R. Hurt

    Our sun is born
    Time: 9.2 billion years


    The sun is one of a few hundred billion stars in the Milky Way. Scientists think it formed from a giant cloud of gas that consisted mostly hydrogen and helium.

    Time: 13.8 billion years

    Today, our cosmos sits at a cool 2.7 Kelvin (minus 270.42 degrees Celsius). The universe is expanding at an increasing rate, in a manner similar to (but many orders of magnitude slower than) inflation.

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

    Physicists think that dark energy—a mysterious repulsive force that currently accounts for about 70% of the energy in our universe—is most likely driving that accelerated expansion.

    Dark energy depiction. Image: Volker Springle/Max Planck Institute for Astrophysics/SP)

    See the full article here .


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    Symmetry is a joint Fermilab/SLAC publication.

  • richardmitnick 10:41 am on October 14, 2018 Permalink | Reply
    Tags: , , , CMB - Cosmic Microwave Background, , , The Jesuit Astronomer Who Conceived of the Big Bang   

    From Discover Magazine: “The Jesuit Astronomer Who Conceived of the Big Bang” 


    From Discover Magazine

    October 12, 2018
    Korey Haynes

    All of the galaxies we see in the distant universe are speeding away from us. This clue led Lemaitre to the idea of an expanding universe: the Big Bang. Credit: NASA/ESA/H. Teplitz and M. Rafelski (IPAC/Caltech)/A. Koekemoer (STScI)/R. Windhorst (Arizona State University)/Z. Levay (STScI)

    NASA/ESA Hubble Telescope

    In 1927, a prescient astronomer named Georges Lemaître looked at data showing how galaxies move. He noticed something peculiar – all of them appeared to be speeding away from Earth. Not only that, but the farther away they were, the faster they went. He determined a mathematical way to represent this, and connected his relationship to Einstein’s law of General Relativity to produce a grand idea: That of a universe continually expanding. It was a radical idea then, but today it fits with our conception of a universe spawned by a Big Bang.

    Inflationary Universe. NASA/WMAP

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

    If you’re an astronomy trivia buff, the name associated with the Big Bang is Edwin Hubble, who also has a rather famous telescope named after himself. Hubble also came up with the concept, but Lemaître beat him to the punch, though his idea got little attention at the time. Now, he may finally share in the recognition for his revolutionary theory.

    Edwin Hubble at Caltech Palomar Samuel Oschin 48 inch Telescope, (credit: Emilio Segre Visual Archives/AIP/SPL)

    It’s too late to rename the Hubble Space Telescope, which is in its twilight years of use anyway. But astronomers are considering renaming the law that explains how the universe expands, from the Hubble Law to the Hubble-Lemaître Law.

    The matter was brought to a vote in August at a meeting of the International Astronomical Union in Vienna, Austria. This is the same body that decided by a vote in 2006 to demote Pluto from planet to dwarf planet. It’s a decision that still stings for some people, both astronomers and members of the public alike. It’s especially contentious because the vote only included the astronomers who were physically present at the 2006 meeting – a tiny fraction of all IAU members. Seeking to avoid the same ruffled feathers, the IAU is taking a different tack this time. Instead of making a final decision at the meeting, attending members took a straw poll to see if there was widespread interest in the change. There was.

    Now all 13,000-plus members of the IAU will get to have their say in the form of an electronic vote before the end of the year. So who is this priest-scientist they’re considering honoring with a foundational cosmological law?

    Georges Lemaitre was a Catholic priest who was the first to describe the expanding universe. Credit: Courtesy of the Catholic University of Louven

    Georges Lemaître: Soldier, Scientist, Priest

    Georges Lemaître was born in Belgium. He volunteered for service in the First World War, interrupting his engineering studies to do so, and earned a medal for his service. Afterwards, he plunged back into academia, this time in physics and math, and began studies to be a priest at the same time. He earned his PhD in 1920, and was ordained in 1923.

    To some in this increasingly polarized age, it might seem odd for a man to be a soldier and a scientist, a religious and scientific devotee in equal measure. But to Lemaître, it seemed to form a coherent whole. He saw his faith and his research as separate enterprises, which neither conflicted nor aided each other. They were simply parallel explorations of the cosmos, both equally worthy of study and contemplation.

    After he published his theory of an expanding universe, and after Hubble published his, Lemaître continued his ideas, building heavily on Einstein’s mathematically-dense framework. He followed the idea of an expanding universe backwards to a logical conclusion. In 1931, he began discussing his “Primeval Atom Hypothesis,” which stated that the universe began as a single point and has been expanding ever since. He also called it the “Cosmic Egg.”

    Modern audiences will recognize this as an early version of the Big Bang Theory, which sometimes finds itself under attack from those who prefer a divine creation story. But Lemaître faced most of his criticism from fellow scientists, who objected to his theory in large part because it sounded too religious. The idea of a universe that had a beginning flew in the face of the scientific consensus of the time, which preferred a static, unchanging universe.

    But Lemaître’s idea was based on a purely physical argument. Eventually the scientific community came around, and discovered strong evidence for what came to be called the Big Bang. That evidence even includes “fossil radiation,” which Lemaître posited might appear as cosmic rays, but which astronomers eventually discovered as the cosmic microwave background [CMB] radiation.

    Cosmic Background Radiation per Planck



    NASA/COBE 1989 to 1993.


    NASA/WMAP 2001 to 2010

    CMB per ESA/Planck

    ESA/Planck 2009 to 2013

    The Church Weighs In

    It’s worth noting that the pope in Lemaître’s time, Pius XII, was delighted that a Catholic priest had conceived of a scientifically valid “creation” story for the universe. It’s also possible, reading between the lines, that the Church was feeling some guilt about the whole Galileo debacle, and looking to clear their conscience. Lemaître himself was less than pleased by the pope butting in, as he viewed his scientific pursuits as completely separate from his religious views, and didn’t appreciate the pope muddying the waters. His Holiness was persuaded to simmer down, but the Catholic Church remains officially in agreement with the Big Bang Theory, and Lemaître retained his good standing in the Church until his death.

    But so what if Lemaître was an interesting person? The scientific law has been known as Hubble’s Law for decades now. And if we change this, doesn’t that open the door to changing names of all sorts of things? And what does it matter, if the underlying science remains unchanged?

    All valid points. But if science is about anything, it’s about revealing the truth. And the truth is that Lemaître arrived at the discovery first. Doesn’t he therefore deserve the credit?

    Then again, Lemaître himself never contested Hubble’s acclaim. He seemed content to let the science speak for itself, whatever it was called.

    See the full article here .


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  • richardmitnick 7:24 am on August 30, 2018 Permalink | Reply
    Tags: An eternal cycle of Big Bang events, Big Bang, CMB - Cosmic Microwave Background, Conformal Cyclic Cosmology, , Hawking Points- anomalous high energy features in the CMB, , Roger Penrose, ,   

    From University of Oxford via COSMOS: “Black holes from a previous universe shine light on our own” 

    U Oxford bloc

    From University of Oxford



    30 August 2018
    Stephanie Rowlands

    Cold spots are a hot topic in Conformal Cyclic Cosmology.

    Stephen Hawking suggested evidence of previous universes could be detected in the cosmic microwave background. Has he been proved right? Jemal Countess/Getty Images

    Cosmologists say they have found remnants of a bygone universe in the afterglow of the Big Bang found in the Cosmic Microwave Background (CMB).

    CMB per ESA/Planck

    ESA/Planck 2009 to 2013

    The discovery gives weight to the controversial theory of Conformal Cyclic Cosmology, or CCC, that suggests our universe is just one of many, built from the remains of a previous one in the Big Bang 13.6 billion years ago.

    The theory describes an eternal cycle of Big Bang events, repeating into the far distant future, the end of our universe giving rise to a new one.

    A team led by Oxford University mathematics emeritus Roger Penrose, a former collaborator of the late Stephen Hawking, claims in a new paper lodged on the preprint server arXiv to have found signs of so-called Hawking Points, anomalous high energy features in the CMB.

    Inside Penrose’s universe
    06 Dec 2010
    Cycles of Time: An Extraordinary New View of the Universe
    Roger Penrose
    2010 Bodley Head £25.00 hb 320pp


    Penrose and colleagues say that these anomalies were made from the last moments of black holes evaporating through “Hawking radiation”.

    Although black holes are famous for never releasing any light, Hawking proposed a subtle way for light and particles to escape over time.

    Through quantum mechanical effects, every black hole slowly shrinks and fades, losing its energy through Hawking radiation.

    “This burst of energy from a now decayed black hole then spreads out quickly in our newly formed universe, leaving a warm central point with a cooling spot around it,” says astronomer Alan Duffy from Australia’s Swinburne University and Lead Scientist of the Royal Institution of Australia, who was not involved in the research.

    “In other words, they have proposed that we can search for an echo of a previous universe in the CMB.”

    Conformal Cyclic Cosmology strongly conflicts with the current standard model explaining the evolution of the universe.

    “Unlike previous cyclic universe models, there is no ‘Big Crunch’ where everything comes together again,” explains Duffy.

    “Instead CCC links the similarity of the current accelerating expansion of the universe by dark energy with early expansion of inflation in the Big Bang.”

    While mathematically the two epochs of expansion are similar, not all cosmologists are convinced that the Big Bang eventually leads to another Big Bang from a future empty universe.

    The results from Penrose and colleagues are likely to be met with skepticism by many mainstream cosmologists.

    Penrose first claimed [Concentric circles in WMAP data may provide evidence of violent pre-Big-Bang activity] to have detected Hawking points in 2010. Other researchers shot down the claim in flames, arguing that his discoveries were nothing more than random noise contained in the data.

    NASA/WMAP 2001 to 2010

    Inflationary Universe. NASA/WMAP

    Lambda-Cold Dark Matter, Accelerated Expansion of the Universe, Big Bang-Inflation (timeline of the universe) Date 2010 Credit: Alex Mittelmann Cold creation

    See the full article here.

    Please help promote STEM in your local schools.

    Stem Education Coalition

    U Oxford campus

    Oxford is a collegiate university, consisting of the central University and colleges. The central University is composed of academic departments and research centres, administrative departments, libraries and museums. The 38 colleges are self-governing and financially independent institutions, which are related to the central University in a federal system. There are also six permanent private halls, which were founded by different Christian denominations and which still retain their Christian character.

    The different roles of the colleges and the University have evolved over time.

  • richardmitnick 8:47 am on July 18, 2018 Permalink | Reply
    Tags: , , , CMB - Cosmic Microwave Background, , , , ,   

    From European Space Agency: “From an almost perfect Universe to the best of both worlds” 

    ESA Space For Europe Banner

    From European Space Agency

    17 July 2018

    Jan Tauber
    ESA Planck Project Scientist
    European Space Agency
    Email: jan.tauber@esa.int

    Markus Bauer
    ESA Science Communication Officer
    Tel: +31 71 565 6799
    Mob: +31 61 594 3 954
    Email: markus.bauer@esa.int

    CMB per Planck

    ESA/Planck 2009 to 2013

    It was 21 March 2013. The world’s scientific press had either gathered in ESA’s Paris headquarters or logged in online, along with a multitude of scientists around the globe, to witness the moment when ESA’s Planck mission revealed its ‘image’ of the cosmos. This image was taken not with visible light but with microwaves.

    Whereas light that our eyes can see is composed of small wavelengths – less than a thousandth of a millimetre in length – the radiation that Planck was detecting spanned longer wavelengths, from a few tenths of a millimetre to a few millimetres. Most importantly, it had been generated at very beginning of the Universe.

    Collectively, this radiation is known as the cosmic microwave background, or CMB. By measuring its tiny differences across the sky, Planck’s image had the ability to tell us about the age, expansion, history, and contents of the Universe. It was nothing less than the cosmic blueprint.

    Astronomers knew what they were hoping to see. Two NASA missions, COBE in the early 1990s and WMAP in the following decade, had already performed an analogous set of sky surveys that resulted in similar images. But those images did not have the precision and sharpness of Planck.


    NASA/COBE 1989 to 1993.


    NASA/WMAP 2001 to 2010

    The new view would show the imprint of the early Universe in painstaking detail for the first time. And everything was riding on it.

    If our model of the Universe were correct, then Planck would confirm it to unprecedented levels of accuracy. If our model were wrong, Planck would send scientists back to the drawing board.

    When the image was revealed, the data had confirmed the model. The fit to our expectations was too good to draw any other conclusion: Planck had showed us an ‘almost perfect Universe’. Why almost perfect? Because a few anomalies remained, and these would be the focus of future research.

    Now, five years later, the Planck consortium has made their final data release, known as the legacy data release. The message remains the same, and is even stronger.

    All cosmological models are based upon Albert Einstein’s General Theory of Relativity. To reconcile the general relativistic equations with a wide range of observations, including the cosmic microwave background, the standard model of cosmology includes the action of two unknown components.

    Firstly, an attractive matter component, known as cold dark matter, which unlike ordinary matter does not interact with light. Secondly, a repulsive form of energy, known as dark energy, which is driving the currently accelerated expansion of the Universe. They have been found to be essential components to explain our cosmos in addition to the ordinary matter we know about. But as yet we do not know what these exotic components actually are.

    CMB temperature and polarisation

    Planck was launched in 2009 and collected data until 2013. Its first release – which gave rise to the almost perfect Universe – was made in the spring of that year. It was based solely on the temperature of the cosmic microwave background radiation, and used only the first two sky surveys from the mission.

    The data also provided further evidence for a very early phase of accelerated expansion, called inflation, in the first tiny fraction of a second in the Universe’s history, during which the seeds of all cosmic structures were sown.

    Lambda-Cold Dark Matter, Accelerated Expansion of the Universe, Big Bang-Inflation (timeline of the universe) Date 2010 Credit: Alex Mittelmann Cold creation

    Yielding a quantitative measure of the relative distribution of these primordial fluctuations, Planck provided the best confirmation ever obtained of the inflationary scenario.


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

    HPHS Owls

    Lambda-Cold Dark Matter, Accelerated Expansion of the Universe, Big Bang-Inflation (timeline of the universe) Date 2010 Credit: Alex MittelmannColdcreation

    Alan Guth’s notes:

    Besides mapping the temperature of the cosmic microwave background across the sky with unprecedented accuracy, Planck also measured its polarisation, which indicates if light is vibrating in a preferred direction. The polarisation of the cosmic microwave background carries an imprint of the last interaction between the radiation and matter particles in the early Universe, and as such contains additional, all-important information about the history of the cosmos. But it could also contain information about the very first instants of our Universe, and give us clues to understand its birth.

    In 2015, a second data release folded together all data collected by the mission, which amounted to eight sky surveys. It gave temperature and polarisation but came with a caution.

    5 February 2015 New maps from ESA’s Planck satellite uncover the ‘polarised’ light from the early Universe across the entire sky, revealing that the first stars formed much later than previously thought.

    “We felt the quality of some of the polarisation data was not good enough to be used for cosmology,” says Jan. He adds that – of course – it didn’t prevent them from doing cosmology with it but that some conclusions drawn at that time needed further confirmation and should therefore be treated with caution.

    And that’s the big change for this 2018 Legacy data release. The Planck consortium has completed a new processing of the data. Most of the early signs that called for caution have disappeared. The scientists are now certain that both temperature and polarisation are accurately determined.

    “Now we really are confident that we can retrieve a cosmological model based on solely on temperature, solely on polarisation, and based on both temperature and polarisation. And they all match,” says Reno Mandolesi, principal investigator of the LFI instrument on Planck at the University of Ferrara, Italy.


    The history of the Universe

    “Since 2015, more astrophysical data has been gathered by other experiments, and new cosmological analyses have also been performed, combining observations of the CMB at small scales with those of galaxies, clusters of galaxies, and supernovae, which most of the time improved the consistency with Planck data and the cosmological model supported by Planck,” says Jean-Loup Puget, principal investigator of the HFI instrument on Planck at the Institut d’Astrophysique Spatiale in Orsay, France.

    This is an impressive feat and means that cosmologists can be assured that their description of the Universe as a place containing ordinary matter, cold dark matter and dark energy, populated by structures that had been seeded during an early phase of inflationary expansion, is largely correct.

    But there are some oddities that need explaining – or tensions as cosmologists call them. One in particular is related to the expansion of the Universe. The rate of this expansion is given by the so-called Hubble Constant.

    To measure the Hubble constant astronomers have traditionally relied on gauging distances across the cosmos. They can only do this for the relatively local Universe by measuring the apparent brightness of certain types of nearby variable stars and exploding stars, whose actual brightness can be estimated independently. It is a well-honed technique that has been developed over the course of the last century, pioneered by Henrietta Leavitt and later applied, in the late 1920s, by Edwin Hubble and collaborators, who used variable stars in distant galaxies and other observations to reveal that the Universe was expanding.

    Measurements of the Hubble constant
    Released 17/07/2018 3:00 pm
    Copyright ESA/Planck Collaboration

    The evolution of measurements of the rate of the Universe’s expansion, given by the so-called Hubble Constant, over the past two decades. The slightly esoteric units give the velocity of the expansion in km/s for every million parsecs (Mpc) of separation in space, where a parsec is equivalent to 3.26 light-years.
    In recent years, the figure astronomers derive for the Hubble Constant using a wide variety of cutting-edge observations to gauge distances across the cosmos is 73.5 km/s/Mpc, with an uncertainty of only two percent. These measurements are shown in blue.
    Alternatively, the Hubble Constant can also be estimated from the cosmological model that fits observations of the cosmic microwave background, which represents the very young Universe, and calculate a prediction for what the Hubble Constant should be today. Measurements based on this method using data from NASA’s WMAP satellite are shown in green, and those obtained using data from ESA’s Planck mission are shown in red.
    When applied to Planck data, this method gives a lower value of 67.4 km/s/Mpc, with a tiny uncertainty of less than a percent.

    On the one hand, it is extraordinary that two such radically different ways of deriving the Hubble constant – one using the local, mature Universe, and one based on the distant, infant Universe – are so close to each other. On the other hand, in principle these two figures should agree to within their respective uncertainties, causing what cosmologists call a ‘tension’ – an oddity that still needs explaining.

    The single purple point is a measurement obtained through yet another method, using data from the first simultaneous observation of light and gravitational waves emitted by the same source – a pair of coalescing neutron stars.

    The figure astronomers derive for the Hubble Constant using a wide variety of cutting-edge observations, including some from Hubble’s namesake observatory, the NASA/ESA Hubble Space Telescope, and most recently from ESA’s Gaia mission, is 73.5 km/s/Mpc, with an uncertainty of only two percent. The slightly esoteric units give the velocity of the expansion in km/s for every million parsecs (Mpc) of separation in space, where a parsec is equivalent to 3.26 light-years.

    NASA/ESA Hubble Telescope

    ESA/GAIA satellite

    A second way to estimate the Hubble Constant is to use the cosmological model that fits the cosmic microwave background image, which represents the very young Universe, and calculate a prediction for what the Hubble Constant should be today. When applied to Planck data, this method gives a lower value of 67.4 km/s/Mpc, with a tiny uncertainty of less than a percent.

    On the one hand, it is extraordinary that two such radically different ways of deriving the Hubble constant – one using the local, mature Universe, and one based on the distant, infant Universe – are so close to each other. On the other hand, in principle these two figures should agree to within their respective uncertainties. This is the tension, and the question is how can they be reconciled?

    Both sides are convinced that any remaining errors in their measurement methodologies are now too small to cause the discrepancy. So could it be that there is something slightly peculiar about our local cosmic environment that makes the nearby measurement somewhat anomalous? We know for example that our Galaxy sits in a slightly under-dense region of the Universe, which could affect the local value of the Hubble constant. Unfortunately, most astronomers think that such deviations are not large enough to resolve this problem.

    “There is no single, satisfactory astrophysical solution that can explain the discrepancy. So, perhaps there is some new physics to be found,” says Marco Bersanelli, deputy principal investigator of the LFI instrument at the University of Milan, Italy.

    ‘New physics’ means that exotic particles or forces could be influencing the results. Yet, as exciting as this prospect feels, the Planck results place severe constraints on this train of thought because it fits so well with the majority of observations.

    “It is very hard to add new physics alleviating the tension and still keep the standard model’s precise description of everything else that already fits,” says François Bouchet, deputy principal investigator of the HFI instrument at the Institut d’Astrophysique de Paris, France.

    As a result, no one has been able to come up with a satisfactory explanation for the differences between the two measurements, and the question remains to be resolved.

    “For the moment, we shouldn’t get too excited about finding new physics: it could well be that the relatively small discrepancy can be explained by a combination of small errors and local effects. But we need to keep improving our measurements and thinking about better ways to explain it,” says Jan.

    This is the legacy of Planck: with its almost perfect Universe, the mission has given researchers confirmation of their models but with a few details to puzzle over. In other words: the best of both worlds.

    Notes for Editors
    A series of scientific papers describing the new results was published on 17 July and can be downloaded here.

    The Planck Legacy Archive
    More about Planck

    See the full article here .

    Please help promote STEM in your local schools.

    Stem Education Coalition

    The European Space Agency (ESA), established in 1975, is an intergovernmental organization dedicated to the exploration of space, currently with 19 member states. Headquartered in Paris, ESA has a staff of more than 2,000. ESA’s space flight program includes human spaceflight, mainly through the participation in the International Space Station program, the launch and operations of unmanned exploration missions to other planets and the Moon, Earth observation, science, telecommunication as well as maintaining a major spaceport, the Guiana Space Centre at Kourou, French Guiana, and designing launch vehicles. ESA science missions are based at ESTEC in Noordwijk, Netherlands, Earth Observation missions at ESRIN in Frascati, Italy, ESA Mission Control (ESOC) is in Darmstadt, Germany, the European Astronaut Centre (EAC) that trains astronauts for future missions is situated in Cologne, Germany, and the European Space Astronomy Centre is located in Villanueva de la Cañada, Spain.

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  • richardmitnick 10:24 am on July 12, 2018 Permalink | Reply
    Tags: CMB - Cosmic Microwave Background, , , ,   

    From NASA/ESA Hubble Telescope and ESA GAIA Mission: “Hubble and Gaia Team Up to Fuel Cosmic Conundrum” 

    NASA Hubble Banner

    NASA/ESA Hubble Telescope

    From NASA/ESA Hubble Telescope

    ESA/GAIA satellite

    ESA GAIA Mission

    Most precise measurement yet adds to debate over universe’s expansion rate

    Jul 12, 2018

    Ann Jenkins
    Space Telescope Science Institute, Baltimore, Maryland

    Ray Villard
    Space Telescope Science Institute, Baltimore, Maryland

    Adam Riess
    Space Telescope Science Institute, Baltimore, Maryland

    Using the powerful Hubble and Gaia space telescopes, astronomers just took a big step toward finding the answer to the Hubble constant, one of the most important and long-sought numbers in all of cosmology. This number measures the rate at which the universe is expanding since the big bang, 13.8 billion years ago. The constant is named for astronomer Edwin Hubble, who nearly a century ago discovered that the universe was uniformly expanding in all directions. Now, researchers have calculated this number with unprecedented accuracy.

    Intriguingly, the new results further intensify the discrepancy between measurements for the expansion rate of the nearby universe, and those of the distant, primeval universe — before stars and galaxies even existed. Because the universe is expanding uniformly, these measurements should be the same. The so-called “tension” implies that there could be new physics underlying the foundations of the universe.

    The Full Story

    Using the power and synergy of two space telescopes, astronomers have made the most precise measurement to date of the universe’s expansion rate.

    The results further fuel the mismatch between measurements for the expansion rate of the nearby universe, and those of the distant, primeval universe — before stars and galaxies even existed.

    This so-called “tension” implies that there could be new physics underlying the foundations of the universe. Possibilities include the interaction strength of dark matter, dark energy being even more exotic than previously thought, or an unknown new particle in the tapestry of space.

    Combining observations from NASA’s Hubble Space Telescope and the European Space Agency’s (ESA) Gaia space observatory, astronomers further refined the previous value for the Hubble constant, the rate at which the universe is expanding from the big bang 13.8 billion years ago.

    But as the measurements have become more precise, the team’s determination of the Hubble constant has become more and more at odds with the measurements from another space observatory, ESA’s Planck mission, which is coming up with a different predicted value for the Hubble constant.

    Planck mapped the primeval universe as it appeared only 360,000 years after the big bang. The entire sky is imprinted with the signature of the big bang encoded in microwaves. Planck measured the sizes of the ripples in this Cosmic Microwave Background (CMB) that were produced by slight irregularities in the big bang fireball.

    CMB per ESA/Planck

    ESA/Planck 2009 to 2013

    The fine details of these ripples encode how much dark matter and normal matter there is, the trajectory of the universe at that time, and other cosmological parameters.

    These measurements, still being assessed, allow scientists to predict how the early universe would likely have evolved into the expansion rate we can measure today. However, those predictions don’t seem to match the new measurements of our nearby contemporary universe.

    “With the addition of this new Gaia and Hubble Space Telescope data, we now have a serious tension with the Cosmic Microwave Background data,” said Planck team member and lead analyst George Efstathiou of the Kavli Institute for Cosmology in Cambridge, England, who was not involved with the new work.

    “The tension seems to have grown into a full-blown incompatibility between our views of the early and late time universe,” said team leader and Nobel Laureate Adam Riess of the Space Telescope Science Institute and the Johns Hopkins University in Baltimore, Maryland. “At this point, clearly it’s not simply some gross error in any one measurement. It’s as though you predicted how tall a child would become from a growth chart and then found the adult he or she became greatly exceeded the prediction. We are very perplexed.”

    In 2005, Riess and members of the SHOES (Supernova H0 for the Equation of State) Team set out to measure the universe’s expansion rate with unprecedented accuracy. In the following years, by refining their techniques, this team shaved down the rate measurement’s uncertainty to unprecedented levels. Now, with the power of Hubble and Gaia combined, they have reduced that uncertainty to just 2.2 percent.

    Because the Hubble constant is needed to estimate the age of the universe, the long-sought answer is one of the most important numbers in cosmology. It is named after astronomer Edwin Hubble, who nearly a century ago discovered that the universe was uniformly expanding in all directions—a finding that gave birth to modern cosmology.

    Galaxies appear to recede from Earth proportional to their distances, meaning that the farther away they are, the faster they appear to be moving away. This is a consequence of expanding space, and not a value of true space velocity. By measuring the value of the Hubble constant over time, astronomers can construct a picture of our cosmic evolution, infer the make-up of the universe, and uncover clues concerning its ultimate fate.

    The two major methods of measuring this number give incompatible results. One method is direct, building a cosmic “distance ladder” from measurements of stars in our local universe.

    Cosmic distance ladder from measurements of stars in our local universe. http://dinosauriens.info/?u=Cosmic+distance+ladder++Wikipedia

    Another view:

    The other method uses the CMB to measure the trajectory of the universe shortly after the Big Bang and then uses physics to describe the universe and extrapolate to the present expansion rate. Together, the measurements should provide an end-to-end test of our basic understanding of the so-called “Standard Model” of the universe. However, the pieces don’t fit.

    Using Hubble and newly released data from Gaia, Riess’ team measured the present rate of expansion to be 73.5 kilometers (45.6 miles) per second per megaparsec. This means that for every 3.3 million light-years farther away a galaxy is from us, it appears to be moving 73.5 kilometers per second faster. However, the Planck results predict the universe should be expanding today at only 67.0 kilometers (41.6 miles) per second per megaparsec. As the teams’ measurements have become more and more precise, the chasm between them has continued to widen, and is now about 4 times the size of their combined uncertainty.

    Over the years, Riess’ team has refined the Hubble constant value by streamlining and strengthening the “cosmic distance ladder,” used to measure precise distances to nearby and far-off galaxies. They compared those distances with the expansion of space, measured by the stretching of light from nearby galaxies. Using the apparent outward velocity at each distance, they then calculated the Hubble constant.

    To gauge the distances between nearby galaxies, his team used a special type of star as cosmic yardsticks or milepost markers. These pulsating stars, called Cephied variables, brighten and dim at rates that correspond to their intrinsic brightness. By comparing their intrinsic brightness with their apparent brightness as seen from Earth, scientists can calculate their distances.

    Gaia further refined this yardstick by geometrically measuring the distance to 50 Cepheid variables in the Milky Way. These measurements were combined with precise measurements of their brightnesses from Hubble. This allowed the astronomers to more accurately calibrate the Cepheids and then use those seen outside the Milky Way as milepost markers.

    “When you use Cepheids, you need both distance and brightness,” explained Riess. Hubble provided the information on brightness, and Gaia provided the parallax information needed to accurately determine the distances. Parallax is the apparent change in an object’s position due to a shift in the observer’s point of view. Ancient Greeks first used this technique to measure the distance from Earth to the Moon.

    “Hubble is really amazing as a general-purpose observatory, but Gaia is the new gold standard for calibrating distance. It is purpose-built for measuring parallax—this is what it was designed to do,” Stefano Casertano of Space Telescope Science Institute and a member of the SHOES Team added. “Gaia brings a new ability to recalibrate all past distance measures, and it seems to confirm our previous work. We get the same answer for the Hubble constant if we replace all previous calibrations of the distance ladder with just the Gaia parallaxes. It’s a crosscheck between two very powerful and precise observatories.”

    The goal of Riess’ team is to work with Gaia to cross the threshold of refining the Hubble constant to a value of only one percent by the early 2020s. Meanwhile, astrophysicists will likely continue to grapple with revisiting their ideas about the physics of the early universe.

    The Riess team’s latest results are published in the July 12 issue of The Astrophysical Journal.

    See the full article here .


    Please help promote STEM in your local schools.

    Stem Education Coalition

    ESA GAIA Mission Objective
    A global space astrometry mission, Gaia will make the largest, most precise three-dimensional map of our Galaxy by surveying more than a thousand million stars.

    Gaia will monitor each of its target stars about 70 times over a five-year period. It will precisely chart their positions, distances, movements, and changes in brightness. It is expected to discover hundreds of thousands of new celestial objects, such as extra-solar planets and brown dwarfs, and observe hundreds of thousands of asteroids within our own Solar System. The mission will also study about 500 000 distant quasars and will provide stringent new tests of Albert Einstein’s General Theory of Relativity.

    Gaia will create an extraordinarily precise three-dimensional map of more than a thousand million stars throughout our Galaxy and beyond, mapping their motions, luminosity, temperature and composition. This huge stellar census will provide the data needed to tackle an enormous range of important problems related to the origin, structure and evolutionary history of our Galaxy.

    For example, Gaia will identify which stars are relics from smaller galaxies long ago ‘swallowed’ by the Milky Way. By watching for the large-scale motion of stars in our Galaxy, it will also probe the distribution of dark matter, the invisible substance thought to hold our Galaxy together.

    Gaia will achieve its goals by repeatedly measuring the positions of all objects down to magnitude 20 (about 400 000 times fainter than can be seen with the naked eye).

    For all objects brighter than magnitude 15 (4000 times fainter than the naked eye limit), Gaia will measure their positions to an accuracy of 24 microarcseconds. This is comparable to measuring the diameter of a human hair at a distance of 1000 km.

    It will allow the nearest stars to have their distances measured to the extraordinary accuracy of 0.001%. Even stars near the Galactic centre, some 30 000 light-years away, will have their distances measured to within an accuracy of 20%.

    The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center manages the telescope. The Space Telescope Science Institute (STScI), is a free-standing science center, located on the campus of The Johns Hopkins University and operated by the Association of Universities for Research in Astronomy (AURA) for NASA, conducts Hubble science operations.

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  • richardmitnick 3:29 pm on December 1, 2017 Permalink | Reply
    Tags: André Maeder, CMB - Cosmic Microwave Background, , , , , Katie Mack, , The strongest evidence for dark matter comes not from the motions of stars and galaxies “but from the behavior of matter on cosmological scales as measured by signatures in the cosmic microwave back   

    From COSMOS: “Radical dark matter theory prompts robust rebuttals” 

    Cosmos Magazine bloc

    COSMOS Magazine

    01 December 2017
    Richard A Lovett

    Most cosmologists invoke dark energy to explain the accelerating expansion of the universe. A few are not so certain. Mina De La O / Getty

    In 1887, physicists Alfred Michelson and Edward Morley set up an array of prisms and mirrors in an elegant attempt to measure the passage of the Earth through what was then known as “luminiferous ether” – a mysterious substance through which light waves were believed to propagate, like sound waves through air.

    The experiment should have worked, but in one of the most famous results of Nineteenth Century physics no ether movement was detected. That was a head-scratcher until 1905, when Albert Einstein took the results at face value and used them as a cornerstone in developing his theory of relativity.

    Today, physicists are hunting for two equally mysterious commodities: dark matter and dark energy. And maybe, suggests a recent line of research from astrophysicist André Maeder at the University of Geneva, Switzerland, they too don’t exist, and scientists need to again revise their theories, this time to look for ways to explain the universe without the need for either of them.

    Dark matter was first proposed all the way back in 1933, when astrophysicists realised there wasn’t enough visible matter to explain the motions of stars and galaxies. Instead, there appeared to be a hidden component contributing to the gravitational forces affecting their motion. It is now believed that even though we still have not successfully observed it, dark matter is five times more prevalent in the universe than normal matter.

    Dark energy came into the picture more recently, when astrophysicists realised that the expansion of the universe could not be explained without the existence of some kind of energy that provides a repulsive force that steadily accelerates the rate at which galaxies are flying away from each other. Dark energy is believed to be even more prevalent than dark matter, comprising a full 70% of the universe’s total mass-energy.

    Maeder’s argument, published in a series of papers this year in The Astrophysical Journal is that maybe we don’t need dark matter and dark energy to explain these effects. Maybe it’s our concept of Einsteinian space-time that’s wrong.

    His argument begins with the conventional cosmological understanding that the universe started with a Big Bang, about 13.8 billion years ago, followed by continual expansion. But in this mode, there is a possibility that hasn’t been taken into account, he says: “By that I mean the scale invariance of empty space; in other words the empty space and its properties do not change following a dilation or contraction.”

    If so, that would affect our entire understanding of gravity and the evolution of the universe.

    Based on this hypothesis, Maeder found that with the right parameters he could explain the expansion of the universe without dark energy. He could also explain the motion of stars and galaxies without the need for dark matter.

    To say that Maeder’s ideas are controversial is an understatement. Katie Mack, an astrophysicist at the University of Melbourne on Australia, calls them “massively overhyped.” And physicist and blogger Sabine Hossenfelder of the Frankfurt Institute for Advanced Studies, Germany, wrote that while Maeder “clearly knows his stuff,” he does not yet have “a consistent theory.”

    Specifically, Mack notes that the strongest evidence for dark matter comes not from the motions of stars and galaxies, “but from the behavior of matter on cosmological scales, as measured by signatures in the cosmic microwave background [CMB] and the distribution of galaxies.” Gravitational lensing of distant objects by nearer galaxies also reveals the existence of dark matter, she says.

    CMB per ESA/Planck


    Gravitational Lensing NASA/ESA

    Also, she notes that while there are a “whole heap” of ways to modify Einstein’s theories, these are “nothing new and not especially interesting.”

    The challenge, she says, is to reproduce everything, including “dark matter and dark energy’s biggest successes.” Until a new theory can produce “precise agreement” with measurements of a wide range of cosmic variables, she says, there’s no reason “at all” to throw out the existing theory.

    Dark matter researcher Benjamin Roberts, at the University of Reno, Nevada, US, agrees. “The evidence for dark matter is very substantial and comes from a large number of sources,” he says. “Until a single theory can explain all of these observations, there is no reason to doubt the existence of dark matter.”

    That said, this doesn’t mean that “new physics” theories such as Maeder’s should be ignored. “They should be, and are, taken seriously,” he says.

    Or as Maeder puts it, “Nothing can ever be taken for granted.”

    See the full article here .

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  • richardmitnick 4:29 pm on October 15, 2017 Permalink | Reply
    Tags: , CMB - Cosmic Microwave Background, , , , ,   

    From Goddard: “NASA’s James Webb Space Telescope and the Big Bang: A Short Q&A with Nobel Laureate Dr. John Mather” 

    NASA Goddard Banner
    NASA Goddard Space Flight Center

    Oct. 11, 2017
    Maggie Masetti
    NASA’s Goddard Space Flight Center

    Dr. John Mather, a Nobel laureate and the senior project scientist for NASA’s James Webb Space Telescope. Credits: NASA/Chris Gunn

    Q: What is the Big Bang?

    A: The Big Bang is a really misleading name for the expanding universe that we see. We see an infinite universe with distant galaxies all rushing away from each other.

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

    The name Big Bang conveys the idea of a firecracker exploding at a time and a place — with a center. The universe doesn’t have a center, at least not one we can find. The Big Bang happened everywhere at once and was a process happening in time, not a point in time. We know this because 1) we see galaxies rushing away from each other, not from a central point; 2) we see the heat that was left over from early times, and that heat uniformly fills the universe; and 3) we can calculate and imagine what the universe was like when the parts were much closer together, and the calculations match everything we can see.

    Q: Can we see the Big Bang?

    A: No, the Big Bang itself is not something we can see.

    Q: What can we see?

    A: We can see the heat radiation that was there when the universe was young. We see this heat as it was about 380,000 years after the expansion of the universe began 13.8 billion years ago (which is what we refer to as the Big Bang). This heat covers the entire sky and fills the universe. (In fact it still does.) We were able to map it with satellites we (NASA and ESA) built called the Cosmic Background Explorer (COBE), the Wilkinson Microwave Anisotropy Probe (WMAP), and Planck. The universe at this point was extremely smooth, with only tiny ripples in temperature.

    Cosmic Infrared Background, Credit: Michael Hauser (Space Telescope Science Institute), the COBE/DIRBE Science Team, and NASA


    All-sky image of the infant universe, created from nine years of data from the Wilkinson Microwave Anisotropy Probe (WMAP).
    Credits: NASA/WMAP Science Team


    CMB per ESA/Planck


    Q: I heard the James Webb Space Telescope will see back further than ever before. What will Webb see?

    NASA/ESA/CSA Webb Telescope annotated

    A: COBE, WMAP, and Planck all saw further back than Webb, though it’s true that Webb will see farther back than Hubble.

    NASA/ESA Hubble Telescope

    Webb was designed not to see the beginnings of the universe, but to see a period of the universe’s history that we have not seen yet.

    Lambda-Cold Dark Matter, Accelerated Expansion of the Universe, Big Bang-Inflation (timeline of the universe) Date 2010 Credit: Alex MittelmannColdcreation

    Specifically, we want to see the first objects that formed as the universe cooled down after the Big Bang. That time period is perhaps hundreds of millions of years later than the one COBE, WMAP, and Planck were built to see. We think that the tiny ripples of temperature they observed were the seeds that eventually grew into galaxies. We don’t know exactly when the universe made the first stars and galaxies — or how for that matter. That is what we are building Webb to help answer.

    Q: Why can’t Hubble see the first stars and galaxies forming?

    A: The only way we can see back to the time when these objects were forming is to look very far away. Hubble isn’t big enough or cold enough to see the faint heat signals of these objects that are so far away.

    Q: Why do we want to see the first stars and galaxies forming?

    A: The chemical elements of life were first produced in the first generation of stars after the Big Bang. We are here today because of them — and we want to better understand how that came to be! We have ideas, we have predictions, but we don’t know. One way or another the first stars must have influenced our own history, beginning with stirring up everything and producing the other chemical elements besides hydrogen and helium. So if we really want to know where our atoms came from, and how the little planet Earth came to be capable of supporting life, we need to measure what happened at the beginning.

    Dr. John Mather is the senior project scientist for the James Webb Space Telescope. Dr. Mather shares the 2006 Nobel Prize for Physics with George F. Smoot of the University of California for their work using the COBE satellite to measure the heat radiation from the Big Bang.

    The James Webb Space Telescope, the scientific complement to NASA’s Hubble Space Telescope, will be the premier space observatory of the next decade. Webb is an international project led by NASA with its partners, ESA (European Space Agency) and CSA (Canadian Space Agency).

    For more information about the Webb telescope, visit: http://www.webb.nasa.gov or http://www.nasa.gov/webb

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    NASA’s Goddard Space Flight Center is home to the nation’s largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

    Named for American rocketry pioneer Dr. Robert H. Goddard, the center was established in 1959 as NASA’s first space flight complex. Goddard and its several facilities are critical in carrying out NASA’s missions of space exploration and scientific discovery.

    NASA/Goddard Campus

  • richardmitnick 9:33 am on October 9, 2017 Permalink | Reply
    Tags: , , Baryons, , CMB - Cosmic Microwave Background, , , ,   

    From New Scientist: “Half the universe’s missing matter has just been finally found” 


    New Scientist

    9 October 2017
    Leah Crane

    Discoveries seem to back up many of our ideas about how the universe got its large-scale structure
    Andrey Kravtsov (The University of Chicago) and Anatoly Klypin (New Mexico State University). Visualisation by Andrey Kravtsov

    The missing links between galaxies have finally been found. This is the first detection of the roughly half of the normal matter in our universe – protons, neutrons and electrons – unaccounted for by previous observations of stars, galaxies and other bright objects in space.

    Two separate teams found the missing matter – made of particles called baryons rather than dark matter – linking galaxies together through filaments of hot, diffuse gas.

    “The missing baryon problem is solved,” says Hideki Tanimura at the Institute of Space Astrophysics in Orsay, France, leader of one of the groups. The other team was led by Anna de Graaff at the University of Edinburgh, UK.

    Because the gas is so tenuous and not quite hot enough for X-ray telescopes to pick up, nobody had been able to see it before.

    “There’s no sweet spot – no sweet instrument that we’ve invented yet that can directly observe this gas,” says Richard Ellis at University College London. “It’s been purely speculation until now.”

    So the two groups had to find another way to definitively show that these threads of gas are really there.

    Both teams took advantage of a phenomenon called the Sunyaev-Zel’dovich effect that occurs when light left over from the big bang passes through hot gas. As the light travels, some of it scatters off the electrons in the gas, leaving a dim patch in the cosmic microwave background [CMB] – our snapshot of the remnants from the birth of the cosmos.

    CMB per ESA/Planck


    Stack ‘em up

    In 2015, the Planck satellite created a map of this effect throughout the observable universe. Because the tendrils of gas between galaxies are so diffuse, the dim blotches they cause are far too slight to be seen directly on Planck’s map.

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

    Both teams selected pairs of galaxies from the Sloan Digital Sky Survey that were expected to be connected by a strand of baryons. They stacked the Planck signals for the areas between the galaxies, making the individually faint strands detectable en masse.

    Tanimura’s team stacked data on 260,000 pairs of galaxies, and de Graaff’s group used over a million pairs. Both teams found definitive evidence of gas filaments between the galaxies. Tanimura’s group found they were almost three times denser than the mean for normal matter in the universe, and de Graaf’s group found they were six times denser – confirmation that the gas in these areas is dense enough to form filaments.

    “We expect some differences because we are looking at filaments at different distances,” says Tanimura. “If this factor is included, our findings are very consistent with the other group.”

    Finally finding the extra baryons that have been predicted by decades of simulations validates some of our assumptions about the universe.

    “Everybody sort of knows that it has to be there, but this is the first time that somebody – two different groups, no less – has come up with a definitive detection,” says Ralph Kraft at the Harvard-Smithsonian Center for Astrophysics in Massachusetts.

    “This goes a long way toward showing that many of our ideas of how galaxies form and how structures form over the history of the universe are pretty much correct,” he says.

    Journal references: arXiv, 1709.05024
    A Search for Warm/Hot Gas Filaments Between Pairs of SDSS Luminous Red Galaxies

    and 1709.10378v1
    Missing baryons in the cosmic web revealed by the Sunyaev-Zel’dovich effect

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

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