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  • richardmitnick 3:42 pm on August 6, 2015 Permalink | Reply
    Tags: , , Gravity,   

    From NRAO: “Gravitational Constant Appears Universally Constant, Pulsar Study Suggests” 

    NRAO Icon
    National Radio Astronomy Observatory

    NRAO Banner

    August 6, 2015
    Contact: Charles E. Blue
    (434) 296-0314; cblue@nrao.edu

    1
    A 21-year study of a pair of ancient stars — one a pulsar and the other a white dwarf — helps astronomers understand how gravity works across the cosmos. The study was conducted with the NSF’s Green Bank Telescope and the Arecibo Observatory. Credit: B. Saxton (NRAO/AUI/NSF)

    Gravity, one of the four fundamental forces of nature, appears reassuringly constant across the Universe, according to a decades-long study of a distant pulsar. This research helps to answer a long-standing question in cosmology: Is the force of gravity the same everywhere and at all times? The answer, so far, appears to be yes.

    Astronomers using the National Science Foundation’s (NSF) Green Bank Telescope (GBT) in West Virginia and its Arecibo Observatory in Puerto Rico conducted a 21-year study to precisely measure the steady “tick-tick-tick” of a pulsar known as PSR J1713+0747.

    1
    GBT

    Arecibo
    Arecibo Observatory

    This painstaking research produced the best constraint ever of the gravitational constant measured outside of our Solar System.

    Pulsars are the rapidly spinning, superdense remains of massive stars that detonated as supernovas. They are detected from Earth by the beams of radio waves that emanate from their magnetic poles and sweep across space as the pulsar rotates. Since they are phenomenally dense and massive, yet comparatively small – a mere 20–25 kilometers across – some pulsars are able to maintain their rate of spin with a consistency that rivals the best atomic clocks on Earth. This makes pulsars exceptional cosmic laboratories to study the fundamental nature of space, time, and gravity.

    This particular pulsar is approximately 3,750 light-years from Earth. It orbits a companion white dwarf star and is one of the brightest, most stable pulsars known. Previous studies show that it takes about 68 days for the pulsar to orbit its white dwarf companion, meaning they share an uncommonly wide orbit. This separation is essential for the study of gravity because the effect of gravitational radiation – the steady conversion of orbital velocity to gravitational waves as predicted by [Albert]Einstein – is incredibly small and would have negligible impact on the orbit of the pulsar. A more pronounced orbital change would confound the accuracy of the pulsar timing experiment.

    “The uncanny consistency of this stellar remnant offers intriguing evidence that the fundamental force of gravity – the big ‘G’ of physics – remains rock-solid throughout space,” said Weiwei Zhu, an astronomer formerly with the University of British Columbia in Canada and lead author on a study accepted for publication in the Astrophysical Journal. “This is an observation that has important implications in cosmology and some of the fundamental forces of physics.”

    “Gravity is the force that binds stars, planets, and galaxies together,” said Scott Ransom, a co-author and astronomer with the National Radio Astronomy Observatory in Charlottesville, Va. “Though it appears on Earth to be constant and universal, there are some theories in cosmology that suggest gravity may change over time or may be different in different corners of the Universe.”

    The data taken throughout this experiment are consistent with an unchanging gravitational constant in a distant star system. Earlier related research in our own Solar System, which was based on precise laser ranging studies of the Earth-Moon distance, found the same consistency over time.

    “These results – new and old – allow us to rule out with good confidence that there could be ‘special’ times or locations with different gravitational behavior,” added Ingrid Stairs, a co-author from the University of British Columbia in Canada. “Theories of gravity that are different from general relativity often make such predictions, and we have put new restrictions on the parameters that describe these theories.”

    Zhu concluded: “The gravitational constant is a fundamental constant of physics, so it is important to test this basic assumption using objects at different places, times, and gravitational conditions. The fact that we see gravity perform the same in our Solar System as it does in a distant star system helps to confirm that the gravitational constant truly is universal.”

    This work was part of the North American Nanohertz Observatory for Gravitational Waves (NANOGrav), a Physics Frontiers Center funded by the NSF.

    The GBT is located in the National Radio Quiet Zone, which protects the incredibly sensitive telescope from unwanted radio interference, enabling it to study pulsars and other astronomical objects.

    The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

    See the full article here.

    Please help promote STEM in your local schools.

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    Stem Education Coalition

    The NRAO operates a complementary, state-of-the-art suite of radio telescope facilities for use by the scientific community, regardless of institutional or national affiliation: the Very Large Array (VLA), the Robert C. Byrd Green Bank Telescope (GBT), and the Very Long Baseline Array (VLBA)*.

    ALMA Array

    NRAO ALMA

    NRAO GBT
    NRAO GBT

    NRAO VLA
    NRAO VLA

    The NRAO is building two new major research facilities in partnership with the international community that will soon open new scientific frontiers: the Atacama Large Millimeter/submillimeter Array (ALMA), and the Expanded Very Large Array (EVLA). Access to ALMA observing time by the North American astronomical community will be through the North American ALMA Science Center (NAASC).
    *The Very Long Baseline Array (VLBA) comprises ten radio telescopes spanning 5,351 miles. It’s the world’s largest, sharpest, dedicated telescope array. With an eye this sharp, you could be in Los Angeles and clearly read a street sign in New York City!

    Astronomers use the continent-sized VLBA to zoom in on objects that shine brightly in radio waves, long-wavelength light that’s well below infrared on the spectrum. They observe blazars, quasars, black holes, and stars in every stage of the stellar life cycle. They plot pulsars, exoplanets, and masers, and track asteroids and planets.

     
  • richardmitnick 3:21 pm on January 6, 2015 Permalink | Reply
    Tags: Gravity,   

    From Physics: “Focus: First Direct Measurement of Gravity’s Curvature” 

    Physics LogoAbout Physics

    Physics Logo 2

    Physics

    January 5, 2015
    Philip Ball

    By measuring gravity with cold atoms at three different heights simultaneously, a team determined a new property of a gravitational field.

    Earth’s gravitational pull gradually decreases with increasing altitude, and researchers have detected the differences even over several vertical feet within a lab, using the extreme sensitivity of cold atoms. Now a team has taken the next step by measuring the change in this gravity gradient produced by a large mass, using measurements at three different heights. They say their technique could improve gravity-based mapping of variations in rock density in geology and prospecting, and it could also boost the precision of tests of general relativity and measurements of the gravitational constant.

    f
    Physics guides oil exploration. Measuring the curvature of the gravitational field could be useful in the oil industry, where prospectors perform sensitive gravity measurements to search for underground deposits. (iStockphoto.com/SGV)

    The technique of atom interferometry enables distance measurements with extremely high precision, by exploiting the atoms’ quantum-mechanical wavelike nature. It has been used previously to measure the strength of gravitational fields and also the rate of change in those fields over some distance (the gradient). Together such measurements permit Newton’s gravitational constant G to be determined. It is currently known to within about 100 parts per million, a much lower precision than other fundamental constants. More accurate measurements would allow higher-precision tests of the theory of general relativity.


    Atom Interferometry

    Measuring gravity at two close locations gives the gradient as the difference between the two divided by their separation distance; measuring at three locations gives the rate of change of the gradient, which is also called the curvature of the field. This experiment was proposed in 2002, and now a team in Italy, led by Guglielmo Tino of the University of Florence and the National Institute of Nuclear Physics (INFN), has carried it out. Previously, Tino and his colleagues determined G by measuring gravity at two different heights with a similar experiment.

    To measure gravity at three locations simultaneously, the team launched three clouds of ultracold atoms to three different heights inside a meter-long vertical pipe. Surrounding the top half of the pipe was 516kg of tungsten alloy weights, to increase the variation in the gravitational field. Near the peaks of their trajectories, the atoms were irradiated with a rapid series of laser pulses from the top and bottom of the pipe.

    In the team’s technique, the first pulse separates each cloud into two populations—one that absorbs two photons, sending it into an excited state and also providing a momentum boost, and a second population that remains in the ground state. The extra momentum causes the first population to fall a different distance during a fixed time, which leads to a gravity-dependent difference in the number of quantum wave cycles that elapse, compared with the ground-state population. Two more wave pulses recombine the populations, allowing them to interfere. From the interference effects the researchers can calculate the difference in the lengths of the two populations’ trajectories, a difference that depends on the gravitational acceleration. The team measured variations in the gravitational acceleration of a few millionths of a percent and calculated the average curvature to be 1.4×10−5s−2m−1, which is virtually identical to the value they predicted.

    Measuring the curvature of a gravitational field could improve the measurement of G, says Tino. A common method involves measuring the field strength and gradient as a heavy mass is moved between one detector and another. But by making two separate measurements of the gradient at different positions simultaneously, the new technique could eliminate systematic sources of error without having to move the mass, which can introduce errors from shifts of the apparatus.

    The curvature could also be useful for mapping gravity changes in the earth, which are used to deduce buried geological structures and to find oil reservoirs. Even if the density changes are small, the curvature can alter dramatically if the density change is abrupt, like a step edge. So measuring gravity curvature could improve the spatial resolution of such density maps.

    “Measuring the gravitational force is sensitive to everything underground,” says Holger Müller of the University of California at Berkeley, who uses atom interferometry to make ultraprecise measurements for probing fundamental physics. “Measuring the gravity gradient enhances the sensitivity to nearby objects, and measuring the [curvature] does so even more.” A practical, curvature-measuring device would be “a great achievement,” Müller says.

    This research is published in Physical Review Letters.

    See the full article here.

    Please help promote STEM in your local schools.

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    Stem Education Coalition

    Physicists are drowning in a flood of research papers in their own fields and coping with an even larger deluge in other areas of physics. How can an active researcher stay informed about the most important developments in physics? Physics highlights a selection of papers from the Physical Review journals. In consultation with expert scientists, the editors choose these papers for their importance and/or intrinsic interest. To highlight these papers, Physics features three kinds of articles: Viewpoints are commentaries written by active researchers, who are asked to explain the results to physicists in other subfields. Focus stories are written by professional science writers in a journalistic style and are intended to be accessible to students and non-experts. Synopses are brief editor-written summaries. Physics provides a much-needed guide to the best in physics, and we welcome your comments (physics@aps.org).

     
  • richardmitnick 10:04 am on November 7, 2014 Permalink | Reply
    Tags: , , , , Gravity,   

    From Ethan Siegel: ” How far does gravity reach?” 

    Starts with a bang
    Starts with a Bang

    Nov 7, 2014
    Ethan Siegel

    “In my dreams and visions, I seemed to see a line, and on the other side of that line were green fields, and lovely flowers, and beautiful white ladies, who stretched out their arms to me over the line, but I couldn’t reach them no-how. I always fell before I got to the line.” –Harriet Tubman

    It’s the end of the week once again, which means we get to take a look at your reader submissions for Ask Ethan, and choose my favorite to share with you. This week’s entry comes from one of my readers who’s been following Starts With A Bang the longest (since my first few months of blogging way back in 2008): Frank Burdge. He asks the following head-scratcher:

    If the Universe is not infinite, then what can be said about the range of the gravitational and electromagnetic forces?

    This is actually an incredibly profound question, when you think about it. Consider what we know about the gravitational and electromagnetic forces, first off.

    i1
    Image credit: Regents Physics, via http://aplusphysics.com/wordpress/regents/tag/inverse-square-law/.

    It isn’t the magnitude of the forces, or the nature of attraction/repulsion that I want you to consider, but rather the fact that — at long ranges — these are inverse-square forces, meaning that as you double the distance between two such objects, the force between them drops to one-fourth what it was at the previous distance. This is a very special relationship, and not only do gravitation and electromagnetism, so do some other important physical properties, such as the effects of light, sound, and radiation.

    Why is this very special? Consider how any of these things — light from a star, for example — spread out as you move farther away from the source.

    i2
    Image credit: Wikimedia Commons user Borb.

    They move radially outward in a sphere, so that a pulse — of light, again, for example — would spread out in an ever expanding spherical shell. Now, why is this special? Because the surface area of a sphere has a very specific formula: A = 4πr^2, where the “r^2” is the important part.

    Why? Because if the area expands according to r^2, but the force drops according to an inverse square law (i.e., r^-2), then we can say that phenomenon has an infinite range. This means you can draw a sphere of any size centered around an object — a gravitational source (a mass), an electric source (a charge), a light source (a star), etc. — and the total amount of stuff acting on that sphere, whether it be force or flux, will be the same when you add up all the different parts of the sphere. This is true not only for the whole sphere, but for any given amount of solid angle on the sphere!

    i3
    Image credit: R Nave of Hyperphysics, via http://hyperphysics.phy-astr.gsu.edu/hbase/forces/isq.html.

    So that’s what we mean by gravitation being an “infinite range” force.

    But the Universe — at the very least, the part of it observable and accessible to us — is not infinite at all! Quite to the contrary, despite the fact that we can see the starlight coming from hundreds of billions of galaxies, that’s not even such a big number. It’s a beautiful sight, and it boggles the mind to look at. (Seriously, take some time and look at it!) But in no way — despite its grandeur — should you conflate its vastness with infinity.

    i4
    Image credit: NASA, ESA, R. Windhorst, S. Cohen, M. Mechtley, and M. Rutkowski (Arizona State University, Tempe), R. O’Connell (University of Virginia), P. McCarthy (Carnegie Observatories), N. Hathi (University of California, Riverside), R. Ryan (University of California, Davis), H. Yan (Ohio State University), and A. Koekemoer (Space Telescope Science Institute).

    Sure, it seems pretty big, but when you consider that there are billions of times that many grains of sand on Earth’s beaches as there are galaxies in the observable Universe, it doesn’t seem so big. The reason we can’t access more has to do with the fact that the Universe hasn’t been around forever, but rather has only had about 13.8 billion years since the Big Bang for things like light (and gravitation) to reach out towards us.

    i5
    Image credit: James Schombert of University of Oregon, via http://abyss.uoregon.edu/~js/ast121/lectures/lec06.html.

    Or more accurately, to reach spherically outward away from their sources. We do the same thing: the gravitation from every particle in our bodies, on our planet and in our galaxy has been reaching out, “grabbing” at the speed of gravity (which is the speed of light) with a force falling off in magnitude as ~1 / r^2 (but reaching out with an increasing area according to ~r^2) since what we conceive as “our Universe” began.

    i6
    Image credit: WiseGEEK, via http://www.wisegeek.org/what-happened-after-the-big-bang.htm#.

    Now, this — the observable Universe, the part reachable by light, gravity, and other finite-speed phenomenon — is not to be confused with however big (or possibly infinite) the entire Universe, including the unobservable part, actually is.

    18
    Images credit: Rob Knop, via http://www.galacticinteractions.org/?p=1623, of the observable Universe at the moment the Universe could first be described by the Big Bang (L), and of the unobservable Universe as well at the same moment (R).

    We have good reasons to believe that the entire Universe is far bigger than the observable parts of it are, but our signals are unable to reach it, due to the fact that there’s only been a finite amount of time that we’ve been emitting signals and that the speed at which these signals propagate is also finite.

    But this is not a bug with our Universe: it’s a feature!

    i9
    Image credit: European Gravitational Observatory, Lionel BRET/EUROLIOS.

    Imagine the Universe if signals propagated infinitely fast, or if we could feel the gravitation, see the light, or otherwise experience the effects of things from far beyond what ought to be accessible to us.

    We’d find ourselves — and likely many other parts of our Universe — catastrophically pulled in a random direction, seemingly without cause. We’d have the entire night sky lit up by sources that ought never to have reached our eyes.

    i10
    Image credit: James Schombert of University of Oregon, via http://abyss.uoregon.edu/~js/ast123/lectures/lec15.html.

    And we, ourselves, would be exerting far more force that we’ve had any physical right to do. In short, the laws of physics would break down, as General Relativity could no longer describe where we live, there would be a catastrophe of too much energy density in our Universe, and — as a consequence of that gravitational binding energy — the Universe itself would inevitably recollapse in short order.

    i11
    Image credit: Shashi M. Kanbur of SUNY Oswego, via http://oswego.edu/~kanbur/.

    To quote Egon from Ghostbusters, “It would be bad.”

    So what we have, instead, is gravitation, electromagnetism, and all the other “infinite range” forces reaching the distances they could have reached after traveling at the speed of light in a 13.8 billion year old Universe that’s expanded according to our own unique history, or about 46 billion light years. This is — since the speed of gravity and the speed of light are identical — also equal to the size of our observable Universe in all directions!

    13
    Image credit: Wikimedia Commons user Azcolvin429.

    And that’s how far the range of the gravitational and electromagnetic forces extend! Thanks for a tough but informative question, Frank, and if you want to see your question featured on Ask Ethan, send in your questions and suggestions here. The next column could be all about whatever you choose!

    See the full article here.

    Starts With A Bang! is a blog/video blog about cosmology, physics, astronomy, and anything else I find interesting enough to write about. I am a firm believer that the highest good in life is learning, and the greatest evil is willful ignorance. The goal of everything on this site is to help inform you about our world, how we came to be here, and to understand how it all works. As I write these pages for you, I hope to not only explain to you what we know, think, and believe, but how we know it, and why we draw the conclusions we do. It is my hope that you find this interesting, informative, and accessible.

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  • richardmitnick 9:39 pm on March 30, 2014 Permalink | Reply
    Tags: , , , , Gravity,   

    From Science@NASA: “NASA Announces Results of Epic Space-Time Experiment” 2011 

    NASA Science Science News

    [This is from 2011, but it just hit NASA’s Twitter feed]

    May 4, 2011
    Dr. Tony Phillips

    [Albert Einstein] was right again. There is a space-time vortex around Earth, and its shape precisely matches the predictions of Einstein’s theory of gravity.

    ae
    Dr. Albert Einstein, Nobel Laureate

    Researchers confirmed these points at a press conference today at NASA headquarters where they announced the long-awaited results of Gravity Probe B (GP-B).

    NASA Gravity Probe B
    Gravity Probe B (GP-B)

    “The space-time around Earth appears to be distorted just as general relativity predicts,” says Stanford University physicist Francis Everitt, principal investigator of the Gravity Probe B mission.

    vortex
    An artist’s concept of GP-B measuring the curved spacetime around Earth.

    “This is an epic result,” adds Clifford Will of Washington University in St. Louis. An expert in Einstein’s theories, Will chairs an independent panel of the National Research Council set up by NASA in 1998 to monitor and review the results of Gravity Probe B. “One day,” he predicts, “this will be written up in textbooks as one of the classic experiments in the history of physics.”

    Time and space, according to Einstein’s theories of relativity, are woven together, forming a four-dimensional fabric called “space-time.” The mass of Earth dimples this fabric, much like a heavy person sitting in the middle of a trampoline. Gravity, says Einstein, is simply the motion of objects following the curvaceous lines of the dimple.

    If Earth were stationary, that would be the end of the story. But Earth is not stationary. Our planet spins, and the spin should twist the dimple, slightly, pulling it around into a 4-dimensional swirl. This is what GP-B went to space in 2004 to check.

    The idea behind the experiment is simple:

    Put a spinning gyroscope into orbit around the Earth, with the spin axis pointed toward some distant star as a fixed reference point. Free from external forces, the gyroscope’s axis should continue pointing at the star–forever. But if space is twisted, the direction of the gyroscope’s axis should drift over time. By noting this change in direction relative to the star, the twists of space-time could be measured.

    In practice, the experiment is tremendously difficult.

    gyro
    One of the super-spherical gyroscopes of Gravity Probe B.

    The four gyroscopes in GP-B are the most perfect spheres ever made by humans. These ping pong-sized balls of fused quartz and silicon are 1.5 inches across and never vary from a perfect sphere by more than 40 atomic layers. If the gyroscopes weren’t so spherical, their spin axes would wobble even without the effects of relativity.

    According to calculations, the twisted space-time around Earth should cause the axes of the gyros to drift merely 0.041 arcseconds over a year. An arcsecond is 1/3600th of a degree. To measure this angle reasonably well, GP-B needed a fantastic precision of 0.0005 arcseconds. It’s like measuring the thickness of a sheet of paper held edge-on 100 miles away.

    “GP-B researchers had to invent whole new technologies to make this possible,” notes Will.

    They developed a “drag free” satellite that could brush against the outer layers of Earth’s atmosphere without disturbing the gyros. They figured out how to keep Earth’s magnetic field from penetrating the spacecraft. And they created a device to measure the spin of a gyro–without touching the gyro. More information about these technologies may be found in the Science@NASA story “A Pocket of Near-Perfection.”

    Pulling off the experiment was an exceptional challenge. But after a year of data-taking and nearly five years of analysis, the GP-B scientists appear to have done it.

    “We measured a geodetic precession of 6.600 plus or minus 0.017 arcseconds and a frame dragging effect of 0.039 plus or minus 0.007 arcseconds,” says Everitt.

    For readers who are not experts in relativity: Geodetic precession is the amount of wobble caused by the static mass of the Earth (the dimple in spacetime) and the frame dragging effect is the amount of wobble caused by the spin of the Earth (the twist in spacetime). Both values are in precise accord with Einstein’s predictions.

    “In the opinion of the committee that I chair, this effort was truly heroic. We were just blown away,” says Will.

    bhy
    An artist’s concept of twisted spacetime around a black hole. Credit: Joe Bergeron of Sky & Telescope magazine.

    The results of Gravity Probe B give physicists renewed confidence that the strange predictions of Einstein’s theory are indeed correct, and that these predictions may be applied elsewhere. The type of spacetime vortex that exists around Earth is duplicated and magnified elsewhere in the cosmos–around massive neutron stars, black holes, and active galactic nuclei.

    “If you tried to spin a gyroscope in the severely twisted space-time around a black hole,” says Will, “it wouldn’t just gently precess by a fraction of a degree. It would wobble crazily and possibly even flip over.”

    In binary black hole systems–that is, where one black hole orbits another black hole–the black holes themselves are spinning and thus behave like gyroscopes. Imagine a system of orbiting, spinning, wobbling, flipping black holes! That’s the sort of thing general relativity predicts and which GP-B tells us can really be true.

    The scientific legacy of GP-B isn’t limited to general relativity. The project also touched the lives of hundreds of young scientists:

    “Because it was based at a university many students were able to work on the project,” says Everitt. “More than 86 PhD theses at Stanford plus 14 more at other Universities were granted to students working on GP-B. Several hundred undergraduates and 55 high-school students also participated, including astronaut Sally Ride and eventual Nobel Laureate Eric Cornell.”

    NASA funding for Gravity Probe B began in the fall of 1963. That means Everitt and some colleagues have been planning, promoting, building, operating, and analyzing data from the experiment for more than 47 years—truly, an epic effort.

    What’s next?

    Everitt recalls some advice given to him by his thesis advisor and Nobel Laureate Patrick M.S. Blackett: “If you can’t think of what physics to do next, invent some new technology, and it will lead to new physics.”

    “Well,” says Everitt, “we invented 13 new technologies for Gravity Probe B. Who knows where they will take us?”

    This epic might just be getting started, after all….

    See the full article here.

    NASA leads the nation on a great journey of discovery, seeking new knowledge and understanding of our planet Earth, our Sun and solar system, and the universe out to its farthest reaches and back to its earliest moments of existence. NASA’s Science Mission Directorate (SMD) and the nation’s science community use space observatories to conduct scientific studies of the Earth from space to visit and return samples from other bodies in the solar system, and to peer out into our Galaxy and beyond. NASA’s science program seeks answers to profound questions that touch us all:

    This is NASA’s science vision: using the vantage point of space to achieve with the science community and our partners a deep scientific understanding of our planet, other planets and solar system bodies, the interplanetary environment, the Sun and its effects on the solar system, and the universe beyond. In so doing, we lay the intellectual foundation for the robotic and human expeditions of the future while meeting today’s needs for scientific information to address national concerns, such as climate change and space weather. At every step we share the journey of scientific exploration with the public and partner with others to substantially improve science, technology, engineering and mathematics (STEM) education nationwide.

    NASA


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  • richardmitnick 4:57 pm on April 30, 2013 Permalink | Reply
    Tags: , , , , Gravity,   

    From Symmetry: “Matter, antimatter, we all fall down—right?” 

    April 30, 2013
    Ashley WennersHerron

    Scientists perform the first direct investigation into how antimatter interacts with gravity.

    What goes up must come down, the saying goes. But things might work a little differently with antimatter.
    A CERN-based experiment has taken the first step in investigating exactly how antimatter interacts with gravity.

    men
    Photo: CERN

    Atimatter particles should mimic those of matter particles. If it turns out that there is a difference, it will be a sign of dramatically new physics.
    CERN ALPHA NewSo far, no one has been able to test directly how antimatter interacts with gravity—but the ALPHA experiment has begun to try.

    The ALPHA experiment’s main purpose is to trap and study antihydrogen atoms, the antimatter partners of hydrogen atoms. The antihydrogen atoms are held in place inside a tube by magnetic forces. Physicists on ALPHA have trapped more than 500 antiatoms since 2010. They keep them in their trap for up to about 16 minutes. When they turn off their magnets, the antiatoms fall out of the trap. A highly sensitive detector tracks the antiatoms and records where they first come in contact with matter and annihilate.”

    See the full article here.

    Symmetry is a joint Fermilab/SLAC publication.


     
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