9.1-earthquake 'Shook Gravity'

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Chipper Q
Chipper Q
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9 Aug 2006 21:03:42 UTC
Topic 191669
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    I just ran across an interesting article (that was in the NY Times, by Kenneth Chang) where significant changes in the Earth's gravitational field were measured by satellites during a 9.1-earthquake (that caused the tsunami in the Indian Ocean in 12/04). I was wondering, could there be evidence for GWs in that data? Would this properly be referred to as measuring the 'jerk' of the satellites in their orbits, or the time-rate-of-change of acceleration?

    DanNeely
    DanNeely
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    9.1-earthquake 'Shook Gravity'

    9 Aug 2006 21:46:22 UTC
    Message 43925
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      I suspect not. The signal was probably caused by parts of the earth bouncing up and down several feet, not by distorting spacetime.

      Chipper Q
      Chipper Q
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      Yeah, I'm guessing they'd be

      10 Aug 2006 0:33:41 UTC
      Message 43926
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        Yeah, I'm guessing they'd be too weak, and that the arrangement of satellites was designed to measure a static field... but it seemed like the arrangement of the satellites is similar to the design of the space-based LISA, where the satellites are the test masses. I know the change in the location of mass in the Earth doesn't involve the density of a neutron star, but the detector is much closer to the source...

        Ernesto Solis
        Ernesto Solis
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        Hey Chipper Q Weak or not,

        12 Sep 2006 22:54:38 UTC
        Message 43927
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          Hey Chipper Q

          Weak or not, could there have been a trace of gravitational wave somewhere?

          Are their any other sources(short gravitationsal waves) other than just LISA?
          Just curious!
          Ernie S
          Team Art Bell
          God Bless

          Have a good day Chipper Q

          Chipper Q
          Chipper Q
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          RE: Weak or not, could

          13 Sep 2006 19:13:14 UTC
          Message 43928
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            Quote:
            Weak or not, could there have been a trace of gravitational wave somewhere?


            Hi Ernie!
            According to theory there would have to be, but considering the mass in question (a small bit of the Earth), I guess the effect would be far weaker than what should already be there, in the stochastic background of gravitational waves. In other words, sources like neutron stars and black holes, having a great deal more mass per unit volume, are the only kinds of objects that will make waves big enough to be detected, even though they're much farther away. Hopefully that's correct.

            LISA is the Laser Interferometer Space Antenna, planned to be launched around 2015. One of the neatest things about it is that it wouldn't be affected by any of the noise (like the ground vibrating from passing cars and trucks) that the ground-based detectors have to contend with...

            Ernesto Solis
            Ernesto Solis
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            RE: RE: Weak or not,

            14 Sep 2006 5:26:02 UTC
            Message 43929 in response to message 43928
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              Quote:
              Quote:
              Weak or not, could there have been a trace of gravitational wave somewhere?

              Hi Ernie!
              According to theory there would have to be, but considering the mass in question (a small bit of the Earth), I guess the effect would be far weaker than what should already be there, in the stochastic background of gravitational waves. In other words, sources like neutron stars and black holes, having a great deal more mass per unit volume, are the only kinds of objects that will make waves big enough to be detected, even though they're much farther away. Hopefully that's correct.

              LISA is the Laser Interferometer Space Antenna, planned to be launched around 2015. One of the neatest things about it is that it wouldn't be affected by any of the noise (like the ground vibrating from passing cars and trucks) that the ground-based detectors have to contend with...

              Thanks Chipper Q

              The web page for LISA is interesting. I wonder if something different might
              be developing by 2015.

              Have a Chipper day
              Ernie

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