Re: gravity waves

Marcel LeBel wrote:
> tessel@xxxxxx wrote:
> ....
> > Since gtr is much more precise about all this than my rather glib verbal
> > description, astronomers are eagerly awaiting the first direct detection
> > of gravitational waves, which might come as early as next year. (The
> > subterranean LIGO and GEO instruments, three in all, newly insulated
> > against perturbing influences like the rumbling of railcars in adjacent
> > states and tumbleweeds blowing around the surface, are taking data at
> > this very minute, if I am not mistaken.)
> >
> This is all very nice and, as you say, very expensive. This is like a
> small scale space program. I mean, all the achievements derived to
> obtain excruciating dampening and precision in all parts of their
> systems....
>
> But all things being equal under gtr, the effects of a gravitational
> wave should affect space-time as a whole. I mean it should be expected
> to affect equally both space contraction and time dilation. Wouldn't it
> be much simpler and cheaper to just compare two very precise clocks to
> check when they BOTH miss a beat or something like that? A coincidence
> detection scheme with a few clocks could even give direction.. That
> would be astronomy.

In the case of linear perturbations, the metric distortion for waves is
purely spacial. It has two components (spin-2) and they are
perpendicular to the propagation direction.

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