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  • richardmitnick 8:47 am on July 18, 2018 Permalink | Reply
    Tags: , , , , , , , NASA WMAP,   

    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

    1
    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.

    COBE/CMB

    NASA/COBE 1989 to 1993.

    CMB per NASA/WMAP

    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.

    3
    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.

    Inflation

    4
    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:
    5

    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
    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.

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    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.

    7
    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 .


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    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 8:51 am on December 4, 2017 Permalink | Reply
    Tags: A winning map, , , , , , NASA WMAP, , ,   

    From Symmetry: “A winning map” 

    Symmetry Mag
    Symmetry

    12/03/17
    Lauren Biron

    1
    Breakthrough Prize. natgeo.com

    The Fundamental Physics Prize recognizes WMAP’s contributions to precision cosmology.

    NASA/WMAP satellite

    Cosmic Microwave Background NASA/WMAP

    The sixth annual Breakthrough Prize in Fundamental Physics has been awarded to an experiment that revolutionized cosmology and mapped the history of our universe. The $3 million prize was given to the science team and five leaders who worked on the Wilkinson Microwave Anisotropy Probe, which investigated matter, the Big Bang and the early conditions of our universe.

    “WMAP surveyed the patterns of the oldest light, and we used the laws of physics to deduce from these patterns answers to our questions,” said Chuck Bennett, the principal investigator of WMAP. He received the award along with Gary Hinshaw, Norman Jarosik, Lyman Page and David Spergel. “Science has let us extend our knowledge of the universe to far beyond our physical reach.”

    The Breakthrough Prizes, which are also awarded in life sciences and mathematics, celebrate both the science itself and the work done by scientists. The award was founded by Sergey Brin, Anne Wojcicki, Jack Ma, Cathy Zhang, Yuri and Julia Milner, Mark Zuckerberg and Priscilla Chan with the goal of inspiring more people to pursue scientific endeavors.

    WMAP, a joint NASA and Princeton University project that ran from 2001 to 2010, has many claims to fame. Scientists have used the spacecraft’s data to determine the age of the universe (13.77 billion years old) and pinpoint when stars first began to shine (about 400 million years after the Big Bang). WMAP results also revealed the density of matter and the surprising makeup of our universe: roughly 71 percent dark energy, 25 percent dark matter and 4 percent visible matter.

    From its home one million miles from Earth, WMAP precisely measured a form of light left over from the Big Bang: the cosmic microwave background (CMB). Researchers assembled this data into a “baby picture” of our universe when it was a mere 375,000 years old. WMAP observations support the theory of inflation—that a rapid period of expansion just after the Big Bang led to fluctuations in the distribution of matter, eventually leading to the formation of galaxies.

    Scientists still hope to unlock more secrets of the universe using the CMB, and various experiments, such as BICEP3 and the South Pole Telescope, are already running to address these cosmological questions.

    BICEP 3 at the South Pole

    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.

    One thing scientists would love to find? A twist on a hot topic: primordial gravitational waves left over from the Big Bang.

    “There is still much we do not understand, such as the first moments of the universe,” Bennett said. “So there will be new breakthroughs in the future.”

    [Interesting to me, reference to BICEP3 ans the South Pole Telescope, but no mention of ESA/Planck, whose map further refined and eclipsed the map by WMAP.

    CMB per ESA/Planck

    ESA/Planck

    An oversite or a slight?]

    See the full article here .

    Please help promote STEM in your local schools.

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    Symmetry is a joint Fermilab/SLAC publication.


     
  • richardmitnick 4:29 pm on October 15, 2017 Permalink | Reply
    Tags: , , , , NASA WMAP, ,   

    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

    1
    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

    NASA/COBE

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    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

    NASA/WMAP

    CMB per ESA/Planck


    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 1:01 pm on July 17, 2017 Permalink | Reply
    Tags: , , , , , , , How big is the universe?, NASA WMAP,   

    From COSMOS: “How big is the universe?” 

    Cosmos Magazine bloc

    COSMOS

    17 July 2017
    Cathal O’Connell

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

    “Space is big. You just won’t believe how vastly, hugely, mind- bogglingly big it is. I mean, you may think it’s a long way down the road to the chemist’s, but that’s just peanuts to space.” – Douglas Adams, Hitchhikers Guide to the Galaxy.

    In one sense the edge of the universe is easy to mark out: it’s the distance a beam of light could have travelled since the beginning of time. Anything beyond is impossible for us to observe, and so outside our so-called ‘observable universe’. You might guess that the distance from the centre of the universe to the edge is simply the age of the universe (13.8 billion years) multiplied by the speed of light: 13.8 billion light years.

    But space has been stretching all this time; and just as an airport walkway extends the stride of a walking passenger, the moving walkway of space extends the stride of light beams. It turns out that in the 13.8 billion years since the beginning of time, a light beam could have travelled 46.3 billion light years from its point of origin in the Big Bang. If you imagine this beam tracing a radius, the observable universe is a sphere whose diameter is double that: 92.6 billion light years.

    “Since nothing is faster than light, absolutely anything could in principle happen outside the observable universe,” says Andrew Liddle, an astronomer at the University of Edinburgh. “It could end and we’d have no way of knowing.”

    But we have good reasons to suspect the entire Universe (capitalised now to distinguish from the merely observable universe) goes on a lot further than the part we can observe – and that it is possibly infinite. So how can we know what goes on beyond the observable universe?

    Imagine a bacterium swimming in a fishbowl. How could it know the true extent of its seemingly infinite world? Well, distortions of light from the curvature of the glass might give it a clue. In the same way, the curvature of the universe tells us about its ultimate size.

    “The geometry of the universe can be of three different kinds,” says Robert Trotta, an astrophysicist at Imperial College London. It could be closed (like a sphere), open (like a saddle) or flat (like a table).

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    Universal geometry: the universe could be closed like sphere, open like a saddle or flat like a table. The first option would make it finite; the other two, infinite.
    Cosmos Magazine.

    The key to measuring its curvature is the cosmic microwave background (CMB) radiation – a wash of light given out by the fireball of plasma that pervaded the universe 400,000 years after the Big Bang. It’s our snapshot of the universe when it was very young and about 1,000 times smaller than it is today.

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

    NASA/COBE

    Cosmic Microwave Background NASA/WMAP

    NASA/WMAP satellite

    CMB per ESA/Planck

    ESA/Planck

    Just as ancient geographers once used the curviness of the Earth’s horizon to work out the size of our planet, astronomers are using the curvinesss of the CMB at our cosmic horizon to estimate the size of the universe.

    The key is to use satellites to measure the temperature of different features in the CMB. The way these features distort across the CMB landscape is used to calculate its geometry. “So determining the size and geometry, of the Universe helps us determine what happened right after its birth,” Trotta says.

    Since the late 1980s, three generations of satellites have mapped the CMB with ever improving resolution, generating better and better estimates of the universe’s curvature. The latest data, released in March 2013, came from the European Space Agency’s Planck telescope. It estimated the curvature to be completely flat, at least to within a measurement certainty of plus or minus 0.4%.

    The extreme flatness of the universe supports the theory of cosmic inflation. This theory holds that in a fraction of a second (10−36 second to be precise) just after its birth, the universe inflated like a balloon, expanding many orders of magnitude while stretching and flattening its surface features.

    Perfect flatness would mean the universe is infinite, though the plus or minus 0.4% margin of error means we can’t be sure. It might still be finite but very big. Using the Planck data, Trotta and his colleagues worked out the minimum size of the actual Universe would have to be at least 250 times greater than the observable universe.

    The next generation of telescopes should improve on the data from the Planck telescope. Whether they will give us a definitive answer about the size of the universe remains to be seen. “I imagine that we will still treat the universe as very nearly flat and still not know well enough to rule out open or closed for a long time to come,” says Charles Bennet, head of the new CLASS array of microwave telescopes in Chile.

    As it turns out, owing to background noise there are fundamental limits to how well we can ever measure the curvature, no matter how good the telescopes get. In July 2016, physicists at Oxford worked out we cannot possibly measure a curvature below about 0.01%. So we still have a ways to go, though measurements so far, and the evidence from inflation theory, has most physicists weighing toward the view the universe is probably infinite. An impassioned minority, however, have had a serious problem with that.

    Getting rid of infinity, the great British physicist Paul Dirac said, is the most important challenge in physics. “No infinity has ever been observed in nature,” notes Columbia University astrophysicist Janna Levin in her 2001 memoir How the Universe got its Spots. “Nor is infinity tolerated in a scientific theory.”

    So how come physicists keep allowing that the universe itself may be infinite? The idea goes back to the founding fathers of physics. Newton, for example, reasoned that the universe must be infinite based on his law of gravitation. It held that everything in the universe attracted everything else. But if that were so, eventually the universe would be pulled towards a single point, in the way that a star eventually collapses under its own weight. This was at odds with his firm belief the universe had always existed. So, he figured, the only explanation was infinity – the equal pull in all directions would keep the universe static, and eternal.

    Albert Einstein, 250 years later at the start of the 20th century, similarly envisioned an eternal and infinite universe. General relativity, his theory of the universe on the grandest scales, plays out on an infinite landscape of spacetime.

    Mathematically speaking, it is easier to propose a universe that goes on forever than to have to deal with the edges. Yet to be infinite is to be unreal – a hyperbole, an absurdity.

    In his short story The Library of Babel, Argentinian writer Jorge Luis Borges imagines an infinite library containing every possible book of exactly 410 pages: “…for every sensible line of straightforward statement, there are leagues of senseless cacophonies, verbal jumbles and incoherences.” Because there are only so many possible arrangements of letters, the possible number of books is limited, and so the library is destined to repeat itself.

    An infinite Universe leads to similar conclusions. Because there are only so many ways that atoms can be arranged in space (even within a region 93 billion light years across), an infinite Universe requires that there must be, out there, another huge region of space identical to ours in every respect. That means another Milky Way, another Earth, another version of you and another of me.

    Physicist Max Tegmark, of the Massachusetts Institute of Technology, has run the numbers. He estimates that, in an infinite Universe, patches of space identical to ours would tend to come along about every 1010115 metres (an insanely huge number, one with more zeroes after it than there are atoms in the observable universe). So no danger of bumping into your twin self down at the shops; but still Levin does not accept it: “Is it arrogance or logic that makes me believe this is wrong? There’s just one me, one you. The universe can’t be infinite.”

    Levin was one of the first theorists to approach general relativity from a new perspective. Rather than thinking about geometry, which describes the shape of space, she looked at its topology: the way it was connected.

    All those assumptions about flat, closed or open universes were only valid for huge, spherical universes, she argued. Other shapes could be topologically ‘flat’ and still finite.

    “Your idea of a donut-shaped universe is intriguing, Homer,” says Stephen Hawking in a 1999 episode of The Simpsons. “I may have to steal it.” Actually, the show’s writers had already stolen the idea from Levin—who published her analysis of a donut-shaped universe in 1998.

    A donut, she noted, actually had – “topologically speaking” – zero curvature because the negative curvature on the inside is balanced by the positive curvature on the outside. The (near) zero curvature measured in the CMB was therefore as consistent with a donut as with a flat surface.

    5
    One ring theory to rule them all: CMB data doesn’t rule out a donut-shape, but it would be an awfully big one. Mehau Kulyk / Getty Images.

    In such a universe, Levin realised, you might cross the cosmos in a spaceship, the way sailors crossed the globe, and find yourself back where you started. This idea inspired Australian physicist Neil Cornish, now based at Montana State University, to think about how the very oldest light, from the CMB, might have circumnavigated the cosmos. If the donut universe were below a threshold size, that would create a telltale signature, which Cornish called “circles in the sky”. Alas, when CMB data came back from the Wilkinson Microwave Anisotropy Probe (WMAP) in 2001, no such signatures were found. That doesn’t rule out the donut theory entirely; but it does mean that the universe, if it is a donut, is an awfully big one.

    Attempts to directly prove or disprove the infinity of the universe seem to lead us to a dead-end, at least with current technology. But we might do it by inference, Cornish believes. Inflation theory does a compelling job of explaining the key features of our universe; and one of the offshoots of inflation is the multiverse theory.

    It’s the kind of theory that, when you first hear it, seems to have sprung from the mind of a science-fiction author indulging in mind-expanding substances. Actually it was first proposed by influential Stanford physicist Andrei Linde in the 1980s. Linde – together with Alan Guth at MIT and Alexei Starobinsky at Russia’s Landau Institute for Theoretical Physics – was one of the architects of inflation theory.

    Guth and Starobinsky’s original ideas had inflation petering out in the first split second after the big bang; Linde, however, had it going on and on, with new universes sprouting off like an everlasting ginger root.

    Linde has since showed that “eternal inflation” is probably an inevitable part of any inflation model. This eternal inflation, or multiverse, model is attractive to Linde because it solves the greatest mystery of all: why the laws of physics seem fine-tuned to allow our existence.

    The strength of gravity is just enough to allow stable stars to form and burn, the electromagnetic and nuclear forces are just the right strength to allow atoms to form, for complex molecules to evolve, and for us to come to be.

    In each newly sprouted universe these constants get assigned randomly. In some, gravity might be so strong that the universe recollapses immediately after its big bang. In others, gravity would be so weak that atoms of hydrogen would never condense into stars or galaxies. With an infinite number of new universes sprouting into and out of existence, by chance one will pop up that is fit for life to evolve.

    6
    Infinite variety: in the the eternal inflation model, new universes sprout off like an everlasting ginger root. Andrei Linde.

    The multiverse theory has its critics, notably another co-founder of inflation theory, Paul Steinhardt. who told Scientific American in 2014: “Scientific ideas should be simple, explanatory, predictive. The inflationary multiverse as currently understood appears to have none of those properties.” Meanwhile Paul Davies at the University of Arizona wrote in The New York Times that “invoking an infinity of unseen universes to explain the unusual features of the one we do see is just as ad hoc as invoking an unseen creator”.

    But in another sense the multiverse is the simpler of the two inflation models. In a few lines of equations, or just a few sentences of speech, the multiverse gives us a mechanism to explain the origin of our universe, just as Charles Darwin’s theory of natural selection explained the origin of species. As Max Tegmark puts it: “Our judgment therefore comes down to which we find more wasteful and inelegant: many worlds or many words.”

    To settle the issue, we will need to know more about what went down in the first split-second of the universe. Perhaps gravitational waves will be the answer, a way to ‘hear’ the vibrations of the big bang itself.

    Whether infinite or finite, stand-alone or one of an endless multitude, the universe is surely a mindbending place. Which brings us back to The Hitchhiker’s Guide to the Galaxy: “If there’s any real truth, it’s that the entire multidimensional infinity of the Universe is almost certainly being run by a bunch of maniacs.”

    See the full article here .

    Please help promote STEM in your local schools.

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  • richardmitnick 9:11 am on July 12, 2017 Permalink | Reply
    Tags: , , , , , , , NASA WMAP   

    From astrobites: “What’s your Cosmology? Ask CMB Maps” 

    Astrobites bloc

    Astrobites

    July 12, 2017
    Gourav Khullar

    Title: Cosmological-parameter determination with Microwave Background Maps
    Authors: G. Jungman, M. Kamionkowski, A. Kosowsky and D. N. Spergel
    First Author’s Institution: Dept. of Physics, Syracuse University, New York, USA

    Status: Physical Review D (1996), [open access]

    There are papers that talk of groundbreaking discoveries. There are papers which review the current status of the field, akin to bringing you up-to-date with what’s going on. And then there are papers that open up portals to new sub-fields, with the clarity of their message and the precision of the questions they pose. Today’s paper is one such publication, which in 1996 started an interesting journey in the world of Cosmic Microwave Background (CMB) and Observational Cosmology.

    The Beginning

    Discovered for the first time in the 1970s, CMB studies have relied on measuring the temperature of this relic radiation today, which has sent photons to us from the era when the universe was essentially a plasma of matter and radiation. This era of the universe is where we can see the earliest ‘CMB photons’, a surface aptly called the surface of last scattering. Measuring its temperature gives us an idea about the energy content of the universe at that surface, which decreases as the photons travel towards us and lose energy in an ever-expanding universe.

    2
    Fig 1. The CMB Temperature map of the entire sky, observed by WMAP (as of 2012). The different colors correspond to different temperatures, at the minute scale of micro-Kelvins.

    NASA/WMAP satellite

    It was discovered in 1992 by the Nobel prize-winning satellite COBE that this radiation was isotropic to one parts in 100000, i.e. the uniformity of the CMB temperature across two points in the sky was only different by 10^-5!

    NASA/COBE

    Following this, studies were undertaken to discuss what these anisotropies, or non-uniformities actually meant. Today, we know of several mechanisms that answer this question – mechanisms that have gained credence with results from CMB telescopes like WMAP, PLANCK, the Atacama Cosmology Telescope, and the South Pole Telescope.

    CMB per ESA/Planck


    ESA/Planck

    3
    The Atacama Cosmology Telescope (ACT) is a six-metre telescope on Cerro Toco in the Atacama Desert in the north of Chile, near the Llano de Chajnantor Observatory.

    South Pole Telescope SPTPOL

    But back in 1996, these programs did not exist. The authors of our paper undertook the task of figuring out the theory of a future mission that could conclusively tell us about the nature of the universe back at the last CMB surface. This in turn, would help us characterize the early universe as well as the evolution of the universe between us and the surface of last scattering. What is the study of the evolution of universe since the big bang, but observational cosmology!

    Cosmological Parameters

    Observational cosmology is a game of measuring the following parameters with utmost accuracy and precision:

    Total Density of the universe Ω – baryonic matter, dark matter, radiation, curvature/space
    Hubble Constant H0, acceleration of the universe
    The Cosmological Constant Λ, responsible for the accelerated expansion of the current universe
    Inflation parameters, to constrain the perturbations of pre-CMB and near-CMB era universe
    Mass of neutrino species, that affect structure formation in the universe
    Ionization history of the universe

    Where do CMB observations come into the picture here? CMB is mostly measured in the form of temperature maps, a representation of the energy of the CMB photons across the sky (now, and by extrapolation back in the early universe). This information is best displayed as temperature differences as a function of angular scales in the sky, or ell’s as they are called. The term ell (or l) comes from the fact that on a 3-D sphere like the universe, the best way to compare two different points is to expand the temperature using spherical harmonics (which have ell’s or l in them), just as we expand points on a 2-D surface in terms of sine and cosine. If ell’s are hard to imagine, angular scales are more intuitive (check top axis on Figure 2)!

    3
    Fig 2. Anisotropies as a function of angular scale (or ell’s) in the sky, as observed by different telescopes e.g. WMAP, Boomerang. The solid line is a theoretical model that fits the observations.

    A better resolution of the telescope allows us to distinguish between temperatures in nearby regions, i.e. at smaller scales (or higher ell, in CMB lingo). A better sensitivity allows us to capture minute differences in this temperature. The authors in today’s paper assume a sensitivity and resolution better than COBE, and talk about their projections of a future experiment (which turned out to be WMAP)!

    CMB Anisotropies: Predictions

    The authors go about their predictions by describing the basic accepted theory (at the time) surrounding CMB generation, and what could have possibly caused the width and peaks of the anisotropies look the way they do (seen in Fig 2). Let’s see if we can capture a few of the ideas put forward here.

    4
    Fig 3. Different predictions of cosmological parameters as a function of ell’s (or angular scale), from today’s paper. Each solid line in each panel is a prediction of the CMB map for a specific value of that parameter, keeping the other three parameters constant.

    1.If the cosmological constant is too high in the universe, it increases the distance between us and the surface of last scattering, and subsequently in the anisotropy map.
    2.Moreover, if there is more structure between us and the CMB because of the evolution of the universe(e.g. galaxy clusters), that would make the photons scatter more off this structure, and hence increase the peaks (or strengths) of these anisotropies.
    3.If more perturbations were going on when the CMB was a plasma(at a time when the universe was tiny and most of the points in the sky were in close proximity with each other), the anisotropies seen at large scale NOW (that used to be close by back then) would be larger. Hence, this would mean higher peaks at lower ell, or higher angular scales.
    4.The biggest peak in Figure 2, is seen at an angular scale (or ell) of the horizon at surface of last scattering. We call this a horizon, because that is literally the edge of the universe that could communicate with each other back in the CMB era. This was a fixed physical scale, but what it looks to us today depends entirely on whether our universe is flat, closed or open. For example, in an open universe (like a sphere), the subtended angular scale would look wider than in a flat universe. Hence, the spectrum would move to a lower ell (or higher scales).

    What has happened since?

    5
    Fig 4.The three squares are 10-square degree patches of the sky. The difference in colors are displaying the different resolution and sensitivities of the three generations of CMB telescopes. COBE kickstarted the field of CMB anistropies, while Planck clearly sets the current standards.

    Predictions like these form the core content of this paper, which led to several anisotropy studies in the future. WMAP, the natural all-sky successor to COBE, put amazing constraints on CMB anisotropies in temperature in 2001 (Fig 1). The Planck satellite is the current standard for CMB studies at low-ell (large angular scales e.g. across the sky), with SPT and ACT contributing to high-ell (smaller angular scale e.g. galaxy clusters) studies. The future is even brighter for CMB (literally, and metaphorically), as we look forward to higher sensitivities, and resolution that helps with smaller and smaller angular scales in the sky.

    As John Carlstrom – astrophysicist at the University of Chicago and a pioneer in CMB studies – rightly says, “CMB is a gift that keeps on giving!”

    See the full article here .

    Please help promote STEM in your local schools.

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    What do we do?

    Astrobites is a daily astrophysical literature journal written by graduate students in astronomy. Our goal is to present one interesting paper per day in a brief format that is accessible to undergraduate students in the physical sciences who are interested in active research.
    Why read Astrobites?

    Reading a technical paper from an unfamiliar subfield is intimidating. It may not be obvious how the techniques used by the researchers really work or what role the new research plays in answering the bigger questions motivating that field, not to mention the obscure jargon! For most people, it takes years for scientific papers to become meaningful.
    Our goal is to solve this problem, one paper at a time. In 5 minutes a day reading Astrobites, you should not only learn about one interesting piece of current work, but also get a peek at the broader picture of research in a new area of astronomy.

     
  • richardmitnick 3:21 pm on January 5, 2017 Permalink | Reply
    Tags: , , , , , , , NASA WMAP   

    From USRA: “Arecibo Observatory casts new light on cosmic microwave background observed by WMAP and PLANCK spacecraft” 

    usra-bloc

    USRA

    January 4, 2017
    PR Contact: Suraiya Farukhi
    sfarukhi@usra.edu
    Universities Space Research Association
    410-740-6224 (o)
    443-812-6945 (c)

    Technical Contact: Joan Schmelz
    jschmelz@usra.edu
    Universities Space Research Association
    787-878-2612 x603

    NAIC/Arecibo Observatory, Puerto Rico, USA
    NAIC/Arecibo Observatory, Puerto Rico, USA

    Arecibo Observatory observations of galactic neutral hydrogen structure confirm the discovery of an unexpected contribution to the measurements of the cosmic microwave background observed by the WMAP and Planck spacecraft.

    NASA WMAP satellite
    NASA WMAP satellite

    ESA/Planck
    “ESA/Planck

    An accurate understanding of the foreground (galactic) sources of radiation observed by these two spacecraft is essential for extracting information about the small-scale structure in the cosmic microwave background believed to be indicative of events in the early universe.

    Cosmic Microwave Background WMAP
    Cosmic Microwave Background WMAP

    CMB per ESA/Planck
    CMB per ESA/Planck

    The new source of radiation in the 22 to 100 GHz range observed by WMAP and Planck appears to be emission from cold electrons (known as free-free emission). While cosmologists have corrected for this type of radiation from hot electrons associated with galactic nebulae where the source temperatures are thousands of degrees, the new model requires electron temperatures more like a few 100 K.

    The spectrum of the small-scale features observed by WMAP and Planck in this frequency range is very nearly flat — a finding consistent with the sources being associated with the Big Bang. At first glance it appears that the spectrum expected from the emission by cold galactic electrons, which exist throughout interstellar space, would be far too steep to fit the data. However, if the sources of emission have a small angular size compared with the beam width used in the WMAP and Planck spacecraft, the signals they record would be diluted. The beam widths increase with lower frequency, and the net result of this “beam dilution” is to produce an apparently flat spectrum in the 22 to 100 GHz range.

    “It was the beam dilution that was the key insight,” noted Dr. Gerrit Verschuur, astronomer emeritus at the Arecibo Observatory and lead author on the paper. “Emission from an unresolved source could mimic the flat spectrum observed by WMAP and Planck.”

    The model invoking the emission from cold electrons not only gives the observed flat spectrum usually attributed to cosmic sources but also predicts values for the angular scale and temperature for the emitting volumes. Those predictions can then be compared with observations of galactic structure revealed in the Galactic Arecibo L-Band Feed Array (GALFA) HI survey.

    “The interstellar medium is much more surprising and important than we have given it credit for,” noted Dr. Joshua Peek, an astronomer at the Space Telescope Science Institute and a co-investigator on the GALFA-HI survey. “Arecibo, with its combination of large area and high resolution, remains a spectacular and cutting edge tool for comparing ISM maps to cosmological data sets.”

    The angular scales of the smallest features observed in neutral hydrogen maps made at Arecibo and the temperature of the apparently associated gas both match the model calculations extremely well. So far only three well-studied areas have been analyzed in such detail, but more work is being planned.

    “It was the agreement between the model predictions and the GALFA-HI observations that convinced me that we might be onto something,” noted Dr. Joan Schmelz, Director, Universities Space Research Association (USRA) at Arecibo Observatory and a coauthor on the paper. “We hope that these results help us understand the true cosmological nature of Planck and WMAP data.”

    The data suggest that the structure and physics of diffuse interstellar matter, in particular of cold hydrogen gas and associated electrons, may be more complex than heretofore considered. Such complexities need to be taken into account in order to produce better foreground masks for application to the high-frequency continuum observations of Planck and WMAP in the quest for a cosmologically significant signal.

    USRA’s Dr. Joan Schmelz will present these findings on January 4, 2017, at a press conference at the American Astronomical Society’s (AAS) meeting at Grapevine, Texas.

    The results were published in the Astrophysical Journal, December 1, 2016, in a paper entitled On the Nature of Small-Scale Structure in the Cosmic Microwave Background Observed by Planck and WMAP by G. L. Verschuur and J. T. Schmelz.

    See the full article here .

    Please help promote STEM in your local schools.

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    USRA is an independent, nonprofit research corporation where the combined efforts of in-house talent and university-based expertise merge to advance space science and technology.

    SIGNIFICANCE & PURPOSE

    USRA was founded in 1969, near the beginning of the Space Age, driven by the vision of two individuals, James Webb (NASA Administrator 1961-1968) and Frederick Seitz (National Academy of Sciences President 1962-1969). They recognized that the technical challenges of space would require an established research base to develop novel concepts and innovative technologies. Together, they worked to create USRA to satisfy not only the ongoing need for innovation in space, but also the need to involve society more broadly so the benefits of space activities would be realized.

     
  • richardmitnick 12:25 pm on December 5, 2014 Permalink | Reply
    Tags: , , , , , , , , NASA WMAP   

    From physicsworld: “Planck offers another glimpse of the early universe” 

    physicsworld
    physicsworld.com

    Dec 4, 2014
    Tushna Commissariat

    Results of four years of observations made by the Planck space telescope provide the most precise confirmation so far of the Standard Model of cosmology, and also place new constraints on the properties of potential dark-matter candidates. That is the conclusion of astronomers working on the €700m mission of the European Space Agency (ESA). Planck studies the intensity and the polarization of the cosmic microwave background (CMB), which is the thermal remnant of the Big Bang. These latest results will no doubt frustrate cosmologists, because Planck has so far failed to shed much light on some of the biggest mysteries of physics, including what constitutes the dark matter and dark energy that appears to dominate the universe.

    e
    Lambda-Cold Dark Matter, Accelerated Expansion of the Universe, Big Bang-Inflation (timeline of the universe)

    ESA Planck
    ESA Planck schematic
    ESA/Planck

    Cosmic Background Radiation Planck
    Cosmic Background Radiation per Planck

    WMAP
    NASA/WMAP spacecraft

    Cosmic Background Radiation per WMAP
    Cosmic Background Radiation per WMAP

    Planck ran from 2009–2013, and the first data were released in March last year, comprising temperature data taken during the first 15 months of observations. A more complete data set from Planck will be published later this month, and is being previewed this week at a conference in Ferrara, Italy (Planck 2014 – The microwave sky in temperature and polarization). So far, Planck scientists have revealed that a previous disagreement of 1–1.5% between Planck and its predecessor – NASA’s Wilkinson Microwave Anisotropy Probe (WMAP) – regarding the mission’s “absolute-temperature” measurements has been reduced to 0.3%.

    Winnowing dark matter

    Planck’s latest measurement of the CMB polarization rules out a class of dark-matter models involving particle annihilation in the early universe. These models were developed to explain excesses of cosmic-ray positrons that have been measured by three independent experiments – the PAMELA mission, the Alpha Magnetic Spectrometer and the Fermi Gamma-Ray Space Telescope.

    INFN PAMELA spacecraft
    PAMELA

    AMS-02
    AMS-02

    NASA Fermi Telescope
    NASA/Fermi

    The Planck collaboration also revealed that it has, for the first time, “detected unambiguously” traces left behind by primordial neutrinos on the CMB. Such neutrinos are thought to have been released one second after the Big Bang, when the universe was still opaque to light but already transparent to these elusive particles. Planck has set an upper limit (0.23 eV/c2) on the sum of the masses of the three types of neutrinos known to exist. Furthermore, the new data exclude the existence of a fourth type of neutrino that is favoured by some models.

    Planck versus BICEP2

    Despite the new data, the collaboration did not give any insights into the recent controversy surrounding the possible detection of primordial “B-mode” polarization of the CMB by astronomers working on the BICEP2 telescope.

    BICEP 2
    BICEP 2 interior
    BICEP 2 with South Pole Telescope

    If verified, the BICEP2 observation would be “smoking-gun” evidence for the rapid “inflation” of the early universe – the extremely rapid expansion that cosmologists believe the universe underwent a mere 10–35 s after the Big Bang. A new analysis of polarized dust emission in our galaxy, carried out by Planck earlier in September, showed that the part of the sky observed by BICEP2 has much more dust than originally anticipated, and while this did not completely rule out BICEP2’s original claim, it established that the dust emission is nearly as big as the entire BICEP2 signal. Both Planck and BICEP2 have since been working together on joint analysis of their data, but a result is still forthcoming.

    [THIS IS THE BEST WE CAN DO UNTIL ESA RELEASES THEIR LATEST FINDINGS FROM PLANCK]

    See the full article here.

    Please help promote STEM in your local schools.

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    PhysicsWorld is a publication of the Institute of Physics. The Institute of Physics is a leading scientific society. We are a charitable organisation with a worldwide membership of more than 50,000, working together to advance physics education, research and application.

    We engage with policymakers and the general public to develop awareness and understanding of the value of physics and, through IOP Publishing, we are world leaders in professional scientific communications.
    IOP Institute of Physics

     
  • richardmitnick 5:51 pm on December 28, 2012 Permalink | Reply
    Tags: , , , , NASA WMAP   

    From NASA: “Wilkinson Microwave Anisotropy Probe” 

    NASA WMAP

    The Wilkinson Microwave Anisotropy Probe (WMAP) is a NASA Explorer mission that launched June 2001 to make fundamental measurements of cosmology — the study of the properties of our universe as a whole. WMAP has been stunningly successful, producing our new Standard Model of Cosmology. WMAP’s data stream has ended. Full analysis of the data is now complete. Publications have been submitted as of 12/20/2012.

    universe

    The WMAP science team has determined, to a high degree of accuracy and precision, not only the age of the universe, but also the density of atoms; the density of all other non-atomic matter; the epoch when the first stars started to shine; the ‘lumpiness’ of the universe, and how that lumpiness depends on scale size. In short, when used alone (with no other measurements), WMAP observations have improved knowledge of these six numbers by a total factor of 68,000, thereby converting cosmology from a field of wild speculation to a precision science.

    WMAP’s ‘baby picture of the universe’ maps the afterglow of the hot, young universe at a time when it was only 375,000 years old, when it was a tiny fraction of its current age of 13.77 billion years. The patterns in this baby picture were used to limit what could have possibly happened earlier, and what happened in the billions of year since that early time. The (mis-named) ‘big bang‘ framework of cosmology, which posits that the young universe was hot and dense, and has been expanding and cooling ever since, is now solidly supported, according to WMAP.

    WMAP observations also support an add-on to the big bang framework to account for the earliest moments of the universe. Called ‘inflation,’ the theory says that the universe underwent a dramatic early period of expansion, growing by more than a trillion trillion-fold in less than a trillionth of a trillionth of a second. Tiny fluctuations were generated during this expansion that eventually grew to form galaxies.

    Remarkably, WMAP’s precision measurement of the properties of the fluctuations has confirmed specific predictions of the simplest version of inflation: the fluctuations follow a bell curve with the same properties across the sky, and there are equal numbers of hot and cold spots on the map. WMAP also confirms the predictions that the amplitude of the variations in the density of the universe on big scales should be slightly larger than smaller scales, and that the universe should obey the rules of Euclidean geometry so the sum of the interior angles of a triangle add to 180 degrees.”

    See the full article here.

    NASA


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