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Space Science Technology

A Fourth Gravitational Wave Has Been Detected ( 67

An anonymous reader quotes a report from The Guardian: Astronomers have made a new detection of gravitational waves and for the first time have been able to trace the shape of ripples sent through spacetime when black holes collide. The announcement, made at a meeting of the G7 science ministers in Turin, marks the fourth cataclysmic black-hole merger that astronomers have spotted using Ligo, the Laser Interferometer Gravitational-Wave Observatory. The latest detection is the first to have also been picked up by the Virgo detector, located near Pisa, Italy, providing a new layer of detail on the three dimensional pattern of warping that occurs during some of the most violent and energetic events in the universe.

A tiny wobble in the signal, picked up by Ligo's twin instruments and the Virgo detector on 14 August, could be traced back to the final moments of the merger of two black holes about 1.8 billion years ago. The black holes, with masses about 31 and 25 times the mass of the sun, combined to produce a newly spinning black hole with about 53 times the mass of the sun. The remaining three solar masses were converted into pure energy that spilled out as deformations that spread outwards across spacetime like ripples across a pond. Detecting these tiny distortions has required detectors sensitive enough to measuring a discrepancy of just one thousandth of the diameter of an atomic nucleus across a 4km laser beam.
A paper about the latest discovery has been accepted for publication in the journal Physical Review Letters.
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A Fourth Gravitational Wave Has Been Detected

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  • by Anonymous Coward on Wednesday September 27, 2017 @10:51PM (#55267317)
    How about, uh, the last 48 hours. Seriously guyz, to the extent that you're able to divulge, what the hell happened? [] Because we're glad you're back, but we really missed you.
  • Test, is it working now?

  • One of the three are here.

    "The gravitational waves were detected on Aug. 14, first at the Livingston, La., observatory. A few thousandths of a second later, they were detected at the Hanford LIGO and shortly after that at the Virgo observatory." []


  • These are some of the rarest astronomical bodies in the universe and we've already detected 4 of them colliding? Wow maybe they are more common than we thought.
    • It turns out that the universe is big. Really big. Even the correct word of astronomically big doesn't convey the full meaning of just how big. 4 is not an astronomically big number.
    • by Anonymous Coward

      It's really fucking spectacular. Like suddenly having hearing after growing up deaf. This is just the beginning of what's going to be possible. Imagine a network of geostationary satellites measuring these interference patterns... Incoming asteroids? Maybe that sounds beyond the reach of precision, but the same was said about LIGO.

  • NPR (Nation Public Radio) posted a story on this: []

    At the end of the story they said that since it was 2 black holes, it was unlikely that there would be any light from the event. What was interesting, was that they stated that there were unconfined reports of either a neutron star colliding with a black hole or with another neutron star a few days later. If this observation is confirmed, then there is a possibility that light could have b

  • Why has LIGO on recently defected waves if it has been running for many years. Did they do some sort of upgrade?
    • Re:Why just recently (Score:4, Informative)

      by Scarred Intellect ( 1648867 ) on Thursday September 28, 2017 @08:54AM (#55268671) Homepage Journal

      The mirrors they had for reflecting the beam back down the tunnel have been SIGNIFICANTLY upgraded. They can measure how much the reflector swings on its pendulum by the impact of said laser itself.

      The Hanford LIGO facility can detect a tractor-trailer moving down I5. The effects of these and any other distortions or disturbances are very similar in nature to the waves they're trying to detect, so much of the early work was spent on identifying these and filtering them out. The mirror upgrades helped. (This all comes from a tour of the facility)

      So, in essence, yes. Upgrades. Physical equipment, sensors, hell, probably even people.

    • It takes time to analyze the data properly and write a decent paper about the findings. There are probably a string of observations in the last run but this one was the most interesting because of the Virgo detector being online.
      • I just want a Ligo app so that the moment Ligo detects a signal I get notified with a chirp and a vibration, so that I can almost feel the wave as it passes.

  • by AlanObject ( 3603453 ) on Thursday September 28, 2017 @01:08PM (#55270449)

    Did I read it correctly that 3 solar masses were converted to energy? Over what period of time I wonder. Our own sun's total output would not consume all its mass over billions of years.

    How big a blast zone did that leave? I can imagine star systems for light years around could have been burnt, destroying civilizations. Has anyone done the numbers?

    • Well who needs civilization anyway.

    • Re: (Score:3, Informative)

      by Anonymous Coward

      Yes you read that correctly - 3 SOLAR MASSES were converted into energy, and the timescale is less than 0.1 seconds.
      In the region right around the merger, the shear in space (how much it was shrinking and stretching) from the gravitational waves was ~50% (ie 1km becomes 2km).
      It is awesome!

    • Has anyone done the numbers?

      Yes, bigly. Believe me.
      People say they are the biggest anybody has ever seen.

  • by snadrus ( 930168 )

    This always happens during times of intensive solar flares.
    I'm thinking the Electric Universe's answer is right.

I have hardly ever known a mathematician who was capable of reasoning. -- Plato