LIGO Scientists Make First-Ever Observation of Gravity Waves
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Stories Firehose All Popular Polls Deals Submit Search Login or Sig1n2 u8p Topics: Devices Build Entertainment Technology Open Source Science YRO Follow us: Slashdot is powered by your submissions, so send in your scoop Nickname: Password: 6-20 characters long Public Terminal Log In Forgot your password? Sign in with Google Facebook Twitter LinkedIn Close Check out the brand new SourceForge HTML5 speed test! Test your internet connection now. Works on all × devices. Second Gravitational Wave Detected From Ancient Black Hole Collision (theguardian.com) Posted by BeauHD on Wednesday June 15, 2016 @11:30PM from the ripples-in-the-fabric-of-spacetime dept. An anonymous reader quotes a report from The Guardian: Physicists have detected ripples in the fabric of spacetime that were set in motion by the collision of two black holes far across the universe more than a billion years ago. The event marks only the second time that scientists have spotted gravitational waves, the tenuous stretching and squeezing of spacetime predicted by Einstein more than a century ago. The faint signal received by the twin instruments of the Laser Interferometer Gravitational Wave Observatory (LIGO) in the US revealed two black holes circling one another 27 times before finally smashing together at half the speed of light. The cataclysmic event saw the black holes, one eight times more massive than the sun, the other 14 times more massive, merge into one about 21 times heavier than the sun. In the process, energy equivalent to the mass of the sun radiated into space as gravitational waves. Writing in the journal Physical Review Letters on Wednesday, the LIGO team describes how a second rush of gravitational waves showed up in their instrument a few months after the first, at 3.38am UK time on Boxing Day morning 2015. An automatic search detected the signals and emailed the LIGO scientists within minutes to alert them. The latest signals arrived at the Livingston detector 1.1milliseconds before they hit the Hanford detector, allowing scientists on the team to roughly work out the position of the collision in the sky. In February, LIGO scientists officially announced the first-ever observation of gravity waves. nasa news physics → FBI Can Access Hundreds of Millions of Face Recognition Photos It's Official: LIGO Scientists Make First-Ever Observation of Gravity Waves Submission: Second Gravitational Wave Detected From Ancient Black Hole Collision Software Industry Has $1 Trillion Economic Impact In US Second Gravitational Wave Detected From Ancient Black Hole Collision 29 More | Reply Login Second Gravitational Wave Detected From Ancient Black Hole Collision Post Load All Comments S10e aFruchll 17239 A Cbbomremvieantetsd L1o7g H Iind/dCerneate an Account C/Soemaments Filter: AScllore: I5nsightful I4nformative I3nteresting F2unny 1The Fine Print: The following comments are owned by whoever posted them. We are not responsible for them in any way. R0 e:ALIENS. (Score:5, Funny) b-1y MobileTatsu-NJG ( 946591 ) on Wednesday June 15, 2016 @11:55PM (#52326841) I2 9tr Miedo rbeu |i lRdeinpgly a L soegnisnor that detects gravity but in all my bench-tests it just kept pointing at your mom. Reply to This Parent Share tNwiicttkenra fmacee:b ook linkedin FPlaasgs awso Irnda:p 6p-r2o0p rcihaateracters long Public Terminal Re:ALIENS. (Score:4, Funny) by PLoopge IRn atz o F(o 9rg6o5t9 y4o7u r) poanss Twhourdr?sday June 16, 2016 @12:04AM (#52326881) Journal I tried building a sensor that detects gravity but in all my bench-tests it just kept pointing at your mom. Close FYI, your dick is not a gravity detecting sensor. Close Reply to This Parent Share twitter facebook linkedin Flag as Inappropriate Re: (Score:1) by Captain Splendid ( 673276 ) It is when it's got so much mass! Re: (Score:3, Informative) by Khyber ( 864651 ) Correction: It must be very tiny to be sensitive enough to accurately detect such distant large masses like GP's mom. Re: (Score:1) by K. S. Kyosuke ( 729550 ) Insufficient vibration insulation. Re: (Score:2) by T.E.D. ( 34228 ) I bet you are by far the best Dozens player in the laboratory. Re: (Score:3) by Lorens ( 597774 ) In the David Weber's "Honor Harrington" universe he uses gravity waves. His gravity waves are faster than light (cue interesting plot details, of course), but the real ones detected by LIGO seem to propagate at something more on the order of 0.01 c. Does someone have a more exact value? Re: ALIENS. (Score:2, Funny) by Anonymous Coward 0.010000000c Re: (Score:2) by Warma ( 1220342 ) Can you elaborate what makes you think, that the detected gravity waves propagate at 0.01c? Re: (Score:3) by Lumpy ( 12016 ) How do you know they are not just reflections off the edge of the glass jar the universe is in? Re: (Score:2) by michelcolman ( 1208008 ) but the real ones detected by LIGO seem to propagate at something more on the order of 0.01 c. Does someone have a more exact value? Sure, as far as we know, the exact value is c. Where did you find 0.01c? The distance between Livingston and Hanford is 3002 km, and the signals were received 1.1 milliseconds apart. In a straight line that would be rougly 3 million km/sec, or 10c. But obviously the signal came in at an angle. If it had come in perpendicular to the line between the two detectors, they would have detected it simultaneously. So it must have come from somewhere in between, I would say around 6 degrees off the perpendicular plan Re: (Score:1) by micahraleigh ( 2600457 ) Should be c. Re: (Score:2) by Maritz ( 1829006 ) That there's millisecond delays at all at the scale we're talking has me unconvinced that we've detected a gravity wave. Hyperskeptical I see. I presume you've read up on all the measures that they take to find the real signal and subtract noise? They weren't sufficient for you? Re: (Score:2) by number6x ( 626555 ) If the gravity waves were travelling faster than the speed of light, we would not have detected them. We wouldn't be here to detect them because gravity waves propagating through spacetime faster than the speed of light would mean that the universe doesn't work and that would be the end of everything. I suggest Misner, Thorne and Wheeler [amazon.com], an appropriately weighty tome, for more information on the nature of space time. whenever I have trouble sleeping, this book, saved from my graduate school days always do Re: (Score:2) by bondsbw ( 888959 ) gravity waves propagating through spacetime faster than the speed of light would mean that the universe doesn't work the way we thought FTFY. Science. Re: (Score:2) by rgbatduke ( 1231380 ) I think you slipped a decimal. The LIGO observatories are roughly 3000 km apart, so a straight line lag between them is around 10 milliseconds. A lag of 1 millisecond meansi that the (essentially plane) wave came in at a small angle relative to the perpendicular plane separating them. The triangle involved would (conveniently enough) have a short leg around 300 km long, and that's still a small angle so without a calculator roughly 0.1 radians on one or the other side of the perpendicular plane. I'm not Re: (Score:2) by LifesABeach ( 234436 ) Maybe you could just ask them how they did it? Re: (Score:2) by rgbatduke ( 1231380 ) If I had any ligoites in my addressbook, sure, but lacking that, posting on /. is a good way to proceed. OTOH, reading the wikipedia page would probably do it too. At the moment I'm making up a physics final and don't have time -- I was just dangling bait to see if I could get a lazy answer in the meantime...;- ) Re: (Score:2) by TheSync ( 5291 ) I'm not certain how they manage to set the azimuthal angle See: Rapid Bayesian position reconstruction for gravitational-wave transients [aps.org] "We introduce BAYESTAR, a rapid, Bayesian, non-Markov chain Monte Carlo sky localization algorithm that takes just seconds to produce probability sky maps that are comparable in accuracy to the full analysis. Prompt localizations from BAYESTAR will make it possible to search electromagnetic counterparts of compact binary mergers." Re: (Score:2) by Dunbal ( 464142 ) * How does a hydroelectric dam grab you? Re: (Score:2) by Dcnjoe60 ( 682885 ) Doesn't all technology that we know of depend on gravity in some form or another? Technology does not exist in nature, it is created. For people to exist to create the technology, they need a planet capable of sustaining life. To have a planet with an atmosphere or even to have a planet at all, requires gravity. Ergo, all technology depends on gravity. › Why? (Score:2) by phantomfive ( 622387 ) Why did it take so long to detect these? I know that there have been plenty of experiments attempting to measure them before. Are the waves smaller than expect, thus harder to detect? What was the thing preventing discovery? 2 hidden comments Re:Why? (Score:5, Informative) by Edis Krad ( 1003934 ) on Thursday June 16, 2016 @12:03AM (#52326877) Are the waves smaller than expect, thus harder to detect? Indeed. They're very small. We're talking about a shift in space the size of a very small fraction of a proton [space.com]. So yes, with the current detectors they're pretty hard to detect. Reply to This Parent Share twitter facebook linkedin Flag as Inappropriate Re:Why? (Score:5, Informative) by MightyMartian ( 840721 ) on Thursday June 16, 2016 @12:33AM (#52326955) Journal The current detectors are the most sensitive instruments ever developed by humanity, and in and of themselves mark a major leap forward in technical ability.