Re: "Will the LIGO Experiment Work?"

On 28 Jan, 15:45, "Ufe" <u...@xxxxxxx> wrote:
     The transverse waves are only observable if the two objects can be
resolved as separate objects (near field radiation). If they cannot be so
resolved (far field radiation) by the gravitational wave detector, they will
be impossible to detect because the detector will experience only the static
field from their common center of gravity. The cyclical field which for
which detection was hoped for will cancel. A further complication in the
detection of the transverse wave is the fact that they will not produce a
'stretching" of the local horizontal, they will produce a "tilting" of the
local vertical. The LIGO array should not capable of detecting the effect
even if it has sufficinet amplitude.

     The longitudinal waves emanating from the center of gravity of the
emitting system always produce far field radiation which cancels completely.
An additional complication results from the fact that any residual component
of the gravitational radiation is attenuated not only by the expected
inverse square law, it suffers an additional attenuation in proportion to
the cube of distance rather than the square of distance do the transverse
waves. It would seem reasonable to assert that there are no longitudinal
waves for LIGO to detect.

That is not stricly true. A single LIGO will indeed detect only
gravity gradients along the line separating mirrors. However LIGO is
international. The Japanese and Europeans have detectors placed in
various directions. These are all linked up via a grid. A computer
integrates all the inputs.

My only doubts about LIGO is that it will detect only short wavelength
gravitational waves. GTR gives us a fourth power law. This means that
separations shorter than a radian rapidly go to zero.


- Ian Parker
.

Relevant Pages

  • Re: Will the LIGO Experiment Work?
    ... The greatest possible gravity wave would occur if its source disappeared ... | Gravitational Observatory - LIGO). ... A typical source for such waves would ... | impossible to detect because the detector will experience only the static ...
    (sci.physics.relativity)
  • Re: "Will the LIGO Experiment Work?"
    ... This will produce negative-going pulse as its gravity vanishes, ... A typical source for such waves would be ... the gravitational wave (as seen at an "infinite distance") ... | resolved by the gravitational wave detector, ...
    (sci.physics)
  • Re: "Will the LIGO Experiment Work?"
    ... A typical source for such waves would be ... distance between the ends of the array, as sensed by Laser inteferometry, to ... resolved by the gravitational wave detector, ... field from their common center of gravity. ...
    (sci.physics.relativity)
  • "Will the LIGO Experiment Work?"
    ... An ambitious experiment to detect gravitational waves from ... distance between the ends of the array, as sensed by Laser inteferometry, to ... resolved by the gravitational wave detector, ... from their common center of gravity. ...
    (sci.physics)
  • "Will the LIGO Experiment Work?"
    ... An ambitious experiment to detect gravitational waves from ... distance between the ends of the array, as sensed by Laser inteferometry, to ... resolved by the gravitational wave detector, ... from their common center of gravity. ...
    (sci.physics.particle)