A Third LIGO Detection of a Black Hole Merger, 3 Billion ly Distant

Discussion in 'Astronomy, Exobiology, & Cosmology' started by danshawen, Jun 2, 2017.

  1. danshawen Valued Senior Member

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    https://www.nytimes.com/2017/06/01/science/black-holes-collision-ligo-gravitational-waves.html?_r=0

    On or about January 4, 2017, a pair of black holes 3 billion light years distant, 19 and 31 solar masses respectively, merged ingo a single object 49 solar masses. which were detected nearly simultaneously at the LIGO detector facilities in Hanford, Washington, and Livingston, Louisiana.

    The event, called GW170204 briefly produced an amount of gravitational wave energy exceeding all of the radiation energy output of all the stars in the known universe.

    Before the LIGO upgrades which enabled greater sensitivity than ever before, we possessed no instrument that was capable of detecting such cataclysmic events.
     
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  3. danshawen Valued Senior Member

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    A tough act to follow. Supernovas are not nearly as energetic. There really is a lot of free energy in the vacuum.

    Pity it would be difficult to harness that sort of energy for space travel. It is, after all, an acoustic wave in space. What if we could set up a sympathetic acoustic resonance with one of those?
     
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  5. Q-reeus Valued Senior Member

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    Are you actually suggesting 'free energy in the vacuum' = GW's??!! Seems so....And seems you have no feel for the infinitesimal coupling strength between GW's and matter. As aLIGO is testament to.
    GR variety GW's are nothing like acoustic waves in a fluid. The two could hardly be more different.
     
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  7. danshawen Valued Senior Member

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    I was hoping you'd finish the thought, and you did.

    This last detected gravity wave swallowed the energy equivalent of three solar masses into those "infinitesimal" GR acoustic waves, and all you get out of that, comparatively speaking, is something with enough energy to produce an acoustic chirp with an amplitude about 1/1000 the diameter of a proton.

    If all of the black holes and stars and dark matter in the known universe were suddenly merged into one coalesced hyper black hole mass, how much energy in terms of solar masses converted to energy would be dumped into the resultant gravity wave? I'm suggesting this as a new empirical measure of the Vacuum Expectation Value.

    In the past, estimates varied by as much as a factor of 10^116. It would be better if we could be just a little more precise.
     
  8. Q-reeus Valued Senior Member

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    According to the cited nytimes article:
    "In the latest LIGO event, a black hole 19 times the mass of the sun and another black hole 31 times the sun’s mass, married to make a single hole of 49 solar masses."
    My arithmetic says 31 + 19 - 49 = 1 solar mass as deficit. Despite some doubt about how precise those initial and final 'BH' masses were, that's all we have to go on. One aint three Dan. It seems a little strange that this third announced aLIGO detection has approx. 1/(3V3) times the amplitude of the famous first detected event. Presumably only showed up after much data crunching to remove noise.
    Why are these initial detections so very remote? Surely must be far more frequent NS merger events within the vastly nearer confines of our galaxy. You would think.
    As a fantasy land exercise, one would first need to know what kind of overall merger distributions were envisaged, Dan. For instance, a spherically or just axially symmetric collapse would produce NO gravitational waves. Think of a number game.
    How would gravitational merger events at all relate to vacuum expectation value - and - for which vacuum field(s)?
    Hmm...at a guess, DE vs Planck energy density just got tossed into the concrete mixer tumbling mix as a 'crucial ingredient'. The mind boggles. Not necessarily a good thing to have a boggled mind.
     
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  9. The God Valued Senior Member

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    There was no EM trace recorded.

    A small subprotonic measurement, after a very high level of noise elimination, backward deduces following...


    1. Existence of BH.
    2. Existence of binary BH, almost an impossobility.
    3. Mass of BH1
    4. Spin of BH1
    5. Mass of BH2
    6. Spin of BH2.
    7. Distance from Earth.

    I bet and I have decent money, that this is going to be quite embarrassing for all those whose names appear in the paper. First paper had few thousand names.

    A guy on some other thread was saying that QM effect of earth is so low, why bother?
     
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  10. Q-reeus Valued Senior Member

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    As per previous threads on this topic, the overwhelmingly likely scenario has any neighbouring dust & gas efficiently vacuum-cleaned during the very lengthy initial inspiral phase. Hence within GR at least, all that could be emitted in the final death inspiral and merger is GW's. Even supposing hypothetical 'gravastars' having a physical surface, extreme redshifting would prevail so any possible EM emission too feeble to detect. The sole means to distinguish models then is in the fine details of GW emission. Except for gravity theories allowing an intrinsic magnetic moment. Even then it's unclear if any EM emission would be detectable - detailed calculations of the likely spectrum have almost certainly never been undertaken.
    What?
     
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  11. danshawen Valued Senior Member

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    Anyone want to bet on whether or not the impending 2022 supernova event will produce any detectable gravity waves?

    Until or unless we actually 'see' a measurable event or detect it going down by some means other than a "burp" or a "chirp", this marvelous new instrument is an uncalibrated one. We won't even know how sensitive or insensitive it really is until or unless this happens.

    We shouldn't stop looking for other means to calibrate it. Is anyone cross checking for any neutrino emission events when these events occur, or has it been successfully argued that such a coincidence would be a post hoc ergo propter hoc fallacy and therefore not 'scientific' enough?

    This argument was an old favorite (and still is) of the tobacco industry. You can still purchase cigarettes and ruin your health while paying cigarette taxes to line the pockets of Donald Trump supporters and chums today because of it. Correlation is not causation, and (therefore) correlation or any attempt to correlate is as unscientific as it is evil. Also known as the 'lung cancer denial' fallacy, because previously, it did not have a name. The tobacco industry in cahoots with government actually IS a conspiracy to make certain health care isn't affordable for those gullible enough to become addicted to smoking tobacco. Ever.
     
    Last edited: Jun 3, 2017
  12. Q-reeus Valued Senior Member

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    An interesting thought. But the merger will be that of two typical stars and so will be the end product. Neither inspiral nor the relatively mild and drawn out explosion would generate anything like the amplitude of GW's aLIGO or similar could detect, despite the relatively close 1800 ly. A conclusion based on reading through:
    https://en.wikipedia.org/wiki/KIC_9832227
    https://en.wikipedia.org/wiki/Luminous_red_nova
    http://www.telegraph.co.uk/science/...ion-suns-will-create-new-star-night-sky-2022/
    Some nice visuals will delight astronomers and provide PBS & ilk grist for some upcoming specials no doubt.
     
    Last edited: Jun 3, 2017
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  13. danshawen Valued Senior Member

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    Yes, that's the one.
     
  14. danshawen Valued Senior Member

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    How fortuitous it is that on schedule with the anticipated 2022 stellar merger event, LIGO is finally online and sensitive enough to set up all of the necessary calibrations for our new toy?

    I just love serendipity.
     
  15. danshawen Valued Senior Member

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    Coupling to gravity waves as LIGO does evidently has the side effect of being able to also CREATE gravity waves, which I find rather interesting:

    http://www.sciencemag.org/news/2017...-detect-gravitational-waves-it-makes-them-too

    So, jiggling a quantum mirror at one LIGO site can affect the motion of the mirrors at one of the other detectors? Well, that is a rather fascinating result, but it does make perfect sense.
     
  16. Q-reeus Valued Senior Member

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    Read just enough of that quite silly article to nearly throw up. How ridiculous. Firstly, the aLIGO detectors are actually very inefficient as secondary GW sources. It only takes high school physics to recognize that. Can you see why Dan?
    As for the rest, wild speculation about mirrors in quantum superposed states?! coupling to any appreciable degree to either the incident GW's or their own secondary re-radiated GW's is just so much tosh. Sure hope anyone handing out grants will see that. Do you agree Dan?
     
  17. danshawen Valued Senior Member

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    No. I would approve a grant in this case.

    Just because it takes a nuclear fusion furnace in space to produce most of the light we uses does not mean that we cannot produce it ourselves with less energy.

    Same goes for the acoustic waves through empty space produced by a pair of merging black holes. Some of the most recent sensitivity upgrades to LIGO involved the use of quantum mirror technology. I don't think we necessarily understand all of the details about the way this new detection method couples to vacuum quantum foam energy, which is basically what they are detecting and filtering to produce the three events we have been talking about, but like radio transmissions of a particular resonant frequency, there probably are other means of exploiting the effect that are more sophisticated than a spark gap or a crystal radio.

    I do like your skepticism, Q-reeus. I do understand that many people still have such concerns about LIGO; Farsight, for one, actually sent me a message on the topic. Not to worry, we will all know as early as 2022 (the stellar merger event) which you have already referenced, whether we are being conned or not, but at this point, I don't think so.
     
  18. Q-reeus Valued Senior Member

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    Too many side issues there to clear up given my limited patience. But to get back to my scepticism re aLIGO as 'efficient GW source' nonsense. Ignoring the inherently tiny coupling between any humanly achievable scale matter distribution and a passing GW, and further ignoring that evidently only short burst events are likely to be detected.....We can look at the relative efficiency of aLIGO vs a truly optimally configured secondary radiator. Supposedly, the two ~ 4km separated ~ 40kg each mirrors act together as 'efficient sources of GW's'. No way.

    They are suspended by fibres so as to avoid excitation by any extraneous vibrations of frequencies anywhere near the GW frequency band looked for. That translates to having effectively zero restoring forces acting on the mirrors as a mass oscillator system. Mind you, there is never any proper motions of the mirrors locally, and the only sense in which they move relative to each other is, in GR GW picture, via creation/annihilation of intervening space orthogonal to the propagation axis. Which means the effective quadrupole moment arm is just hL, with h the GW 'strain' amplitude and L the distance between mirrors. Staggeringly small - yielding that ball park figure of ~ one ten thousandth the diameter of a proton. Plug those figures into a quadrupole mode GW source formula and see what result for radiated power you get Dan!

    Weber and others early on realized to have any hope of detecting such infinitesimal incident GW 'strains', given the then only 'practical' approach being bar detectors, was to design for bar mechanical resonance. Resonantly responding at some assumed optimal incident GW frequency, the bar-as-antenna capture cross-section rises as Q², where Q is the mechanical quality factor of the bar. The original aluminium bar Q was iirc only in the 10,000's, but later refined versions got up into the 10's of millions or maybe more. Even then, the effective cross-section is still extremely small relative to the analogous case of an ordinary dipole antenna receiving EM waves.
    To cap it off, resonant bar GW capture then re-radiation can only utilize those high Q values if the incident GW is effectively monochromatic, unlike the short burst ones so far received.

    So, in summary, the aLIGO mirrors are incredibly inefficient as a secondary source of GW's, having an inherent Q factor of unity. Hence a minuscule effective cross-section.

    The rest of that article garbage about 40kg mirrors at room temp being put into a quantum superposition is just outrageous BS. To then go on and further claim a meaningful coupling to GW's is lunacy of the highest order. Call for the men in white coats now. Sorry Dan if I seem to lack your visionary spirit on such matters.
     
  19. danshawen Valued Senior Member

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    I wouldn't call it "visionary" exactly. Deluded, perhaps. I do wish them to succeed.

    You may or may not recall, this process (actually making GWs) was hinted about on the occasion of the first detection of a GW. They said something to the effect of: our experimental setup is capable of producing a faux control GW signal at any time, and so we have set the experiment up as a double blind detection event scenario.

    If you reflect about that for a minute, this would mean that something they can introduce into the experimental test setup would simultaneously generate a gravity wave detection both in Loisianna and Washington. How would anyone go about doing that?

    This article is the only explanation I have ever been able to find. If it were easy to spoof or hack, it is likely someone would already be doing this, right? Because they have not released sufficient information to allow this, I think it would be safe to assume that either it is not easy to do without spending a lot of money to do so, or else there is something else at work with respect to the enhanced detection which they are not at liberty to present a detailed description of. For the moment, I'm willing to table that and grant them the benefit of the doubt for parts of their apparatus which may be subject to patent litigation for follow on applications.

    This does bear some further explanation on the occasion of the confirmed third GW ever detected and analyzed. Just doing what anyone would expect.

    A set of bluetooth enabled remote infrasound speakers buried in or coupled to the foundation of the building in which the mirrors are housed might just do it (make something that resembles a GW event) too, but that isn't what they are saying they can do.
     
    Last edited: Jun 7, 2017
  20. Q-reeus Valued Senior Member

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    That single highlighted word says all that needs to be said on the matter. As per last post, plug the relevant values into the well-known formula for a mass quadrupole radiator, and see what comes out. Simple.
     
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  21. danshawen Valued Senior Member

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    Don't forget that before the first gravity wave was detected, no one had any clue or even a preconception of what a gravity wave looked like, how strong or how weak it would be, or anything else about them.

    Thorne's consultation on the movie 'Interstellar' demonstrates this very well. They wouldn't throw books from shelves, even if the tidal forces from a black hole merger event might, if you were already dangerously close to the pair when they merged.

    Now because we know what they look like, and know how to detect them, things are much different. Would they really go to the trouble of building a third facility, or putting up satellites if all of this work was a fraud? I for one don't think this is likely.
     
  22. The God Valued Senior Member

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    GW pattern was known.
    And yes they are investing in 3rd facility, it is expected to come up in India.

    But you have raised a good point, no top physicist invested in GW or relativity for that matter, would acknowledge futility of this investment, so future grants would continue.

    My prediction is 3rd facility will dump relativity in first detection itself. I will tell you how. It's a very big gamble being taken up by top general relativists.

    Recall that the first detection (I don't have data for second and third), detection time gap between two facilities was of the order of 10 ms, matches with GW speed at c, but as soon as third facility gets kicked in, the time stamping will establish if GW speed is c or not. The gamble is GR guys feel it will be c and you know my prediction, it won't be c. 2022 will coincide with supernova event, I think that's the inauguration date for third facility.

    If you get a news, that third facility project is being dropped, then get yourself convinced that GR guys are playing safe for few more years.
     
  23. danshawen Valued Senior Member

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    Any energy transfer event that propagates linearly in space does so at the same velocity as c in a vacuum.

    My prediction is that GR will be vindicated in this respect, but the surprise will be that the only kind of energy that is fast enough to escape from the core of a black hole merger is really not "gravity" or GR related at all, or at least, not in the sense we think of it right now. We are seeing the last chip of entanglement energy before whatever is inside becomes permanently "disentangled" with everything that is outside, and this is what causes ripples that are detected, which are more of a timelike than a spacelike nature. This last paragraph is speculation loosely based on existing science. It is also part of the reason I believe that faking a black hole merger (making your own "gravity" waves) by means of the technology used to detect it is not so far fetched.
     

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