Did the detection of gravitational wawes confirmed speed of gravity at c?

Discussion in 'Physics & Math' started by Ultron, Mar 4, 2016.

  1. Ultron Registered Senior Member

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    I wonder if the current detection of gravitational wave at aLIGO has confirmed that gravity changes are moving with speed of light? If yes, then how?
     
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  3. origin Trump is the best argument against a democracy. Valued Senior Member

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    I don't think the LIGO experiment explicitly addressed that, indirectly it did support that gravity propgàtes at c by cofiming the relativity prediction of gravity waves.
     
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  5. Q-reeus Valued Senior Member

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    ajanta, Ultron and origin like this.
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  7. Ultron Registered Senior Member

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  8. Q-reeus Valued Senior Member

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    You're welcome. Trying to 'directly' determine GW propagation speed via phase delay between the two aLIGO facilities is an obvious method but very crude owing to for instance currently irreducible uncertainties in GW incidence angle. As more facilities come on line, triangulation becomes effectual and directional uncertainty should dramatically reduce, but will still not allow any really accurate determination of GW speed. Whereas absence of detectable dispersion, to some extent model dependent but not dramatically so, over such huge distances provides a tight bound on any departure from c.
     
  9. The God Valued Senior Member

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    This is a good question, and the answer is Yes, it did prove .

    First let us consider the separation between two aLIGO facilities, it is around 3000 kms, so a wave travelling at light speed should not take more than 3000 kms/c time, that is 10 ms...the delay was 7 ms, suggesting some angle of incidence while speed at c, with two locations nothing much can be said, so as Qreeus suggested once we have more than 2 locations, we can get a real picture on this front. It will be make or break for GW detection.

    On the other front this detection says two BHs, 1.3 Bly away, 3 Solar Mass Energy released created this GW, how could they say that ? By creating a template that such and such cosmic event would make a GW which will travel at c, and will leave this kind of signature on aLIGO. So the light speed part is built into calculations.....
     

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