Re: Gravitational astronomy

[Jack Uretsky <jlu@HEP.ANL.GOV>]

On Sat, 12 Aug 2000, Glenn A. Carlson wrote:

> > Subject: Re: The Universe
> > Date: Fri, 11 Aug 2000 14:00:45 -0500
> > From: Gary Karshner <Karshner@STMARYTX.EDU>
>
> > Observationally we know there is a limit to how far
> > we can see. The three degree background radiation sets that limit. It comes
> > from a time when the universe became transparent, further than that cannot
> > be seen since radiation swamps out any information.
                OK so far.

> > This physical
> > limitation makes the number of galaxies uncountable physically.

        Since galaxy formation presumably occurred after transparency
(when atoms had recombined), the conclusion does not follow, nor is it
correct.

> I agree that the microwave background sets an observational limit for
> photon astronomy, but what about gravitational radiation?  Isn't it
> possible, if only in principle, to use the gravitational waves emitted
> before the recombination time, when the universe became transparent to
> photons, to study the structure of the early universe?

        Local discrete sources of gravitational radiation would be
massive quadrupoles.  It would be a real shock to find any of these in
the early universe.  I suppose that there well may be a background,
comparable to the microwave background.
        The place to look for papers is the LosAlamos preprint archive.
                                Regards,
                                        Jack