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LIGO Spots Another Gravitational Wave Soon After Powering Back On (newscientist.com)

New submitter nichogenius writes: The latest observation run of LIGO and VIRGO only started April 1st, but has already observed another black hole merger. The LIGO detectors have been offline since the 25th of August, 2017 for a series of upgrades. The latest observational run is the first run where gravitational wave events are being publicly announced as they happen rather than being announced weeks or months later. Few details of the merger are available at this time, but there is some information available on LIGO's twitter and raw details can be obtained from LIGO's event database page.

Gravitational detection events are being publicly broadcast using NASA's VOEvent system. If you know a bit of python, you can setup your own VOEvent client using the pygcn module with example code available in this tutorial.

46 comments

  1. Run! Run to the hills! by Hognoxious · · Score: 1

    It won't do any good, will it?

    --
    Confucius say, "Find worm in apple - bad. Find half a worm - worse."
    1. Re: Run! Run to the hills! by Anonymous Coward · · Score: 0

      Where's NayPK and his GIF files he can't seem to make up his mind about? The other thing is not hearing his drivel is welcome relief. Nothing more from him. Don't believe me? Too bad.

  2. new scientist article by e**(i+pi)-1 · · Score: 5, Informative

    it is nice to see that machine back on and working. I would have liked a bit more background, what actually has changed during the upgrade. It seems that this contained only in a ``premium article" in the new scientist. Fortunately there are other sources where on can look things up: 40 percent more sensitive machine leading to twice the volume of space to be observable. Some main mirrors were replaced, the laser power increased and a technique called ``squeezing" introduced which counteracts the now stronger distortion of the beam. Also new is that detections of events are publicly announced as soon as they are available. Here is the source: https://news.stanford.edu/2019...

    1. Re:new scientist article by epine · · Score: 5, Informative

      You missed improvements in event localization to enable traditional astronomy to zoom in on neutron star mergers with an electromagnetic signature. This includes a wide-aperture radio facility (IIRC) and an improved algorithm to search the probable area. Plus, if they have all three facilities in good working order, they get a smaller statistical banana in space to start with (perhaps to improve again once the Japanese facility begins to participate, which I think is slated for later in the year).

    2. Re:new scientist article by Sique · · Score: 4, Interesting
      I like this quote in the aforementioned link:

      One of the things that makes that interesting is that when the moon goes overhead, the ground goes up and down by about plus or minus six inches. When this bulge travels past the LIGO sites, the arms of the detectors get stretched. The isolation tables have to compensate for that motion so that the distances between the optics doesn’t change.

      --
      .sig: Sique *sigh*
    3. Re: new scientist article by Anonymous Coward · · Score: 0

      Too bad these idjuts didn't measure the effect on time, which slowed down during the stretching.

      Just a ripple in the fabic of spacetime. No gravitational waves to see here people, move along.

    4. Re: new scientist article by Anonymous Coward · · Score: 0

      Thank you mr arm-chair physicist for tell us this vital piece of information.

    5. Re:new scientist article by omfglearntoplay · · Score: 1

      Yeah, the amount the moon affects the dirt under our feet is really weird. My kid was very surprised when it was brought up in his grade school science class.

      https://en.wikipedia.org/wiki/...

    6. Re:new scientist article by Anonymous Coward · · Score: 0

      What was your kid previous understanding, that the moon gravity somehow attracts water but not rock? That would have been even weirder.

    7. Re:new scientist article by tehcyder · · Score: 1

      when the moon goes overhead, the ground goes up and down by about plus or minus six inches

      Yeah sure, if that was true then the moon would make the oceans rise and fall on a regular daily basis, rather than being at sea level all the time.

      What sort of idiots do these so-called scientists take us for?

      --
      To have a right to do a thing is not at all the same as to be right in doing it
    8. Re:new scientist article by skaralic · · Score: 1

      Some main mirrors were replaced, the laser power increased and a technique called ``squeezing" introduced which counteracts the now stronger distortion of the beam.

      What, no Blockchain and AI?

    9. Re: new scientist article by Anonymous Coward · · Score: 0

      Except, a gravity wave IS a ripple in the fabric of spacetime.

    10. Re:new scientist article by BranMan · · Score: 1

      Um... You DO realize that not everywhere has tides, right?

  3. did they control by Anonymous Coward · · Score: 0

    for chris's location
    if he moves or even just jiggles in his double-wide computer chair
    gravity waves will be off the chart

    1. Re:did they control by Anonymous Coward · · Score: 0
  4. first post! by Anonymous Coward · · Score: 0

    First light detected! Errr, umm, first waves detected. And posted.

    1. Re:first post! by Anonymous Coward · · Score: 0

      how does it feel to fail harder than chris

    2. Re:first post! by jfdavis668 · · Score: 1

      Swing and a miss...

    3. Re:first post! by Anonymous Coward · · Score: 0

      Failure is trolling for creimer every day and expecting a different result. Oh, wait. That's the definition for insanity. Never mind.

    4. Re: first post! by koki22 · · Score: 1

      The isolation tables have to compensate for that motion so that the distances between the optics doesnâ(TM)t change https://audacity.onl/ https://findmyiphone.onl/ https://origin.onl/

  5. Thanks for that link. by Anonymous Coward · · Score: 2

    Really. That is what I read Slashdot comments for. Much appreciated.

  6. python? by Anonymous Coward · · Score: 1

    Python? Ew. Come on NASA, you can do better.

  7. Overenthousiastic scientist? by trenien · · Score: 1
    The article talks about detecting 'massive' black holes, and goes on to add them to be around 30x the mass of the Sun.

    Why call upon black holes, then? As far as I remember, you can have stars significantly more massive than that before the collapse into a black hole becomes the only explanation to describe what was observed.

    With only that presented as evidence, it sounds like someone was a bit overeager to justify the LIGO's budget with claims of an extraordinary observation.

    1. Re:Overenthousiastic scientist? by trenien · · Score: 2
      Damn, too quick on the draw....

      overenthUsiastic

    2. Re: Overenthousiastic scientist? by Anonymous Coward · · Score: 0

      Commence fun and requisite picking on LIGO. Or not. I'm not buying the claims of efficiency.

    3. Re:Overenthousiastic scientist? by Sique · · Score: 2

      Because stars tend not to merge with each other, and thus they don't send out strong gravitational waves. As long as they radiate strongly, they would rather repulse each other than merge.

      --
      .sig: Sique *sigh*
    4. Re:Overenthousiastic scientist? by ivano · · Score: 1

      BHs are small compared to their mass-equivalent star size. Because of this they can orbit pretty close to each other before actually merging. This means they can go a percentage of the speed of light when orbiting each other and so create bigger gravitational waves. There is a difference between gravitational waves and gravity.

    5. Re:Overenthousiastic scientist? by trenien · · Score: 3, Informative
      And yet, no physics law prohibits it

      https://en.wikipedia.org/wiki/...

      As a matter of fact, the very same LIGO let us see two neutron stars doing that exactly back in 2017.

      On the other hand, as far as I'm aware, there are no conclusive observation of black holes, which makes for a much more spectacular headline.

    6. Re:Overenthousiastic scientist? by Sique · · Score: 2

      And then there is another reason: You want events that send out gravitational waves with a frequency between 100 Hz and 3000 Hz, because that's where LIGO is sensitive. Thus you are confined in the mass of the objects whose gravitational events you can monitor. For other frequencies you either need much larger instruments (e.g. of the length of the Earth's diameter or even larger), or much higher resolutions for the measurements.

      --
      .sig: Sique *sigh*
    7. Re:Overenthousiastic scientist? by Sique · · Score: 3, Informative

      Neutron stars don't have a large radiation pressure. They are inactive stars. Yes, they accelerate stuff from their accredition disc, and thus they send out huge amounts of particles and synchrotron radiation, but only on their poles. But around their equator, they don't have any radiation pressure at all.

      --
      .sig: Sique *sigh*
    8. Re:Overenthousiastic scientist? by necro81 · · Score: 2

      The physics of a collision of 30x stellar mass stars would be very different than for black holes, if only because stars have a (comparatively) large spatial extent, while the black holes are much more compact and, as a result, can get their masses much closer together before they merge. Compact masses getting close together creates 1) very strong gravitational disturbances and 2) very fast orbital speeds. Large stars can't get their masses close enough, and could not orbit each other fast enough, to be detectable by LIGO.

    9. Re:Overenthousiastic scientist? by dargaud · · Score: 1
      The amount of gravitational waves generated by 2 stars colliding is many orders of magnitude less than 2 black holes colliding: In the black hole merger recently observed by LIGO, about 5% of energy was radiated in the form of gravitational waves. In other words, several suns went out in pure energy. That's a LOT of energy, hence why we can detect black hole collisions, but no way we can detect star collisions.

      Also orbiting black holes loses energy pretty fast due to (again) radiating it as gravitational waves and get closer on a relatively short timespan. Stars don't, so orbiting stars (in double systems) don't collide.

      --
      Non-Linux Penguins ?
    10. Re:Overenthousiastic scientist? by dargaud · · Score: 2

      On the other hand, as far as I'm aware, there are no conclusive observation of black holes, which makes for a much more spectacular headline.

      And by the way, as of an hour ago, that's not true anymore

      --
      Non-Linux Penguins ?
    11. Re:Overenthousiastic scientist? by Anonymous Coward · · Score: 0

      Why call upon black holes, then?

      A black hole with a mass 30x that of the sun is about 200 kilometres across. Two such black holes in a decaying orbit around one another, coming closer and faster, would touch and merge when their orbital period was about 10 milliseconds ... which is why the LIGO signals show a chirping signal with a sine wave shrinking down to a period of milliseconds.

      A star with a mass 30x that of the sun will be at least as big as the sun (1.4 million km). If two such stars are the size of the sun, and in a decaying orbit, they will touch and merge when their orbital period is about 1.4 hours. If they are larger than the sun, their orbital period when they merge will be longer than this. This is much longer and slower than the chirped signal seen by LIGO.

      Merging stars would produce gravitational waves that are too long and slow to explain the signal seen by LIGO.

      (I used Kepler's third law in working out these periods. It's probably not quite right when dealing with two equally-sized orbiting bodies, and there will be some relativistic correction for the black-hole case, but the numbers should be close enough that the conclusion above is valid.)

  8. Re: It does not matter to you by Anonymous Coward · · Score: 0

    You must spend more than 95% of your time on slashdot and you won't find a shred of interest from the readers. How many replies do you actually get? Count them.

  9. So, turning the thing on generates by Anonymous Coward · · Score: 0

    gravitational waves? Maybe that's how they get them all the time then, eh?

    But the billion budgets are paid on schedule.

    Check and mate, sceintists.

    1. Re:So, turning the thing on generates by MightyMartian · · Score: 1

      It's the most sensitive instrument ever developed. The technical leap that made LIGO possible is likely to have a vast number of applications going forward.

      --
      The world's burning. Moped Jesus spotted on I50. Details at 11.
    2. Re:So, turning the thing on generates by Anonymous Coward · · Score: 0

      I would say it is also the most impressive science experiment in the last century. Compare the predicted waveforms to the first detection. Theory transformed into fact. To have a great team, you have to have great players. LIGO definitely has that.

    3. Re:So, turning the thing on generates by Shotgun · · Score: 1

      Billions?

      Dude, its a friggin' concrete pipe with a laser bouncing between a few mirrors. This is some of the cheapest science the modern era has to offer, and for the effort we get to push the envelope of how sensitive we can make instruments.

      and before to blow that off, consider that the latest iteration of the industrial revolution that has driven quality in consumer level products has been driven by accurate measurements. The typical car of the 70's came off the line with the equivalent of 50,000 miles of wear on the engine. They had to be able to fit pistons from multiple manufacturing lines into the same cylinders. The only way to do that productively would be to leave space for clearance. Space that looks exactly the same as normal wear. With better measuring tools and techniques, those tolerance can be closed up, leading to a long list of benefits.

      The scientists say, "You're welcome."

      --
      Aah, change is good. -- Rafiki
      Yeah, but it ain't easy. -- Simba
  10. Re: It does not matter to you by Anonymous Coward · · Score: 0

    I spend very little time on niche sites that cater to the maladjusted and only to remind the audience of what their place, or rather the lack of any, is. I do not care about the reactions of the socially excluded. Their "opinions" hold no importance to me whatsoever. They are worthless.

  11. What I don't get ... by Anonymous Coward · · Score: 0

    I'm a dilettante at Physics, I enjoy read about it but I'm by no means an expert so I've been avidly read about LIGO, but one aspect seems to go completely explained:

    Gravity waves 'stretch' spacetime, so they stretch time as well as space proportionately, so how can LIGO possible detect a time discrepancy?

    The gravity wave must be stretching and contracting time in a direct proportion to how it stretches space, any discrepancy should be zero.

    So what am I missing here?

    1. Re:What I don't get ... by jfdavis668 · · Score: 1

      Stretching spacetime does not necessary imply a change to the time portion. They only impact the space. In normal situations, stretching something would imply accelerating each end away from then toward the other. By what I understand, gravitational waves do not accelerate matter. They stretch space. The objects do not move in relation to space, so there is no time dialation involved.

  12. Re: It does not matter to you by Anonymous Coward · · Score: 0

    Yet here you are commenting. That says all! LMAO

  13. Re: It does not matter to you by Anonymous Coward · · Score: 0

    Just to remind you of your place. I find your misery amusing. :)

  14. How do we know? by Anonymous Coward · · Score: 0

    How do we know these are black hole mergers and not other dark matter gravitational waves?