Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

B LIGO gravity waves

  1. Oct 24, 2017 #1
    https://en.wikipedia.org/wiki/LIGO#/media/File:Simplified_diagram_of_an_Advanced_LIGO_detector.png

    The axis on the bottom of the graph depicts frequencies between 20-1000 Hz which are sound waves. Again, how can a sound wave (gravity waves) propagate in the near vacuum of stellar space that is vacuum?

    ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

    "On September 14, 2015 at 09:50:45 UTC the two detectors of the Laser Interferometer Gravitational-Wave Observatory simultaneously observed a transient gravitational-wave signal. The signal sweeps upwards in frequency from 35 to 250 Hz with a peak gravitational-wave strain of 1.0×10^−21." (Abstract).


    Abbott, B. P. Observation of Gravitational Waves from a Binary Black Hole Merger. Physical Review Letters. 116, 061102. 2016

    ---------------------------------------------------------------------------------------------------------------------------------

    Can you explain how electromagnetic stellar gravity waves (GR) form the effects of sound waves at the LIGO observatory?
     
  2. jcsd
  3. Oct 24, 2017 #2

    Drakkith

    User Avatar

    Staff: Mentor

    Sound waves which are audible to us have frequencies from about 20-20,000 Hz, but other waves exist with these frequencies which are not sound waves. For example, EM waves at this frequency are used for communications.

    As for what these gravitational waves use as a medium, the answer is that they are waves in the metric of spacetime. They are, in short, a propagating temporary change in the geometry of spacetime.

    These waves are gravitational waves. Gravity waves, electromagnetic waves, and sound waves are all something different. Gravity waves are waves on the surface of a fluid, such as the wave on the surface of the ocean, while EM waves are waves in the electromagnetic field (light, radio waves, x-rays, etc) and sound waves are a certain type of wave within a physical medium such as water, air, or even rock.
     
  4. Oct 25, 2017 #3
    In Einstein's paper, "The Foundation of the Generalised Theory of Relativity" (1916), Einstein represents gravity with Maxwell's electromagnetic field using Maxwell's equations.

    dh/dt + rot e = 0...............................................70


    div h = 0...........................................................71


    rot h - de'/dt = i................................................72


    div e' = p"........................................................73

    (Einstein5, § 20). Einstein is representing gravity with Maxwell's electromagnetic field that is based on Faraday's induction effect but a small stone that is affected by gravity yet unaffected by a magnet of Faraday's law and a three inch lead plate does not produce anti-gravity which proves gravity is not an electromagnetic phenomenon. Stellar gravity waves are electromagnetic waves. The same waves as a radio wave.
     
  5. Oct 25, 2017 #4
    Weber experimentally detected gravitational waves that have the frequency of sound (1662 Hz).


    "Further advances are necessary in order to generate and detect gravitational waves in the laboratory." (Weber, Conclusion, 1960).


    "A description is given of the gravitational radiation experiments involving detectors at opposite ends of a 1000 kilometer baseline, at Argonne National Laboratory and the University of Maryland. Sudden increases in detector output are observed roughly once in several days, coincident within the resolution time of 0.25 seconds. The statistics rule out an accidental origin and experiments rule out seismic and electromagnetic effects. It is reasonable to conclude that gravitational radiation is being observed." (Weber, Abstract, 1970).


    "EXPERIMENTS AT 1662 HERTZ" (Weber, Intro, 1970).


    Weber detected gravity waves with the frequency of 1662 Hz using the acoustical vibration of a 750 lb aluminum beam but sound cannot propagate in the vacuum of stellar space.
     
  6. Oct 25, 2017 #5
    Precedence--------Weber
     
  7. Oct 25, 2017 #6

    Drakkith

    User Avatar

    Staff: Mentor

    No he isn't. To quote Einstein, from paragraph 814 on his translated paper at wikisource:

    He's setting up Maxwell's equations in a form which remains invariant regardless of your coordinate system choice.

    That is incorrect.

    The "acoustical vibration" is in the aluminum beam, which is being stressed at the frequency of the passing of the gravitational wave (or would be if he had actually detected a gravitational wave, which he did not), it is not in the vacuum. No sound is propagating through space.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: LIGO gravity waves
  1. Gravity Waves? (Replies: 13)

Loading...