LIGO and LISA

http://www.space.com/scienceastronom...ts_030407.html


Looking for gravity waves is like looking for ET's it seems. If these waves
aren't detected within 20 years
it will be a huge blow to relativity.

On Feb 22, 5:11 am, "TMA" wrote:
http://www.space.com/scienceastronom...ts_030407.html

Looking for gravity waves is like looking for ET's it seems. If these waves
aren't detected within 20 years
it will be a huge blow to relativity.

Hardly.

It is much more likely that the experimentalists cannot reach the
sensitivity needed to distinguish gravity waves from thermal noise on
that timescale. GR will live on until such time as a major
gravitational event occurs close enough that it should be detected but
was not. The signals they are looking for are unbelievably feeble.

My guess is when they get the experiment sensitive enough they will
see them. The behaviour of binary pulsars is exactly in line with what
GR predicts. In fact it was so precisely in line with what GR
predicted that the discreprancies between the first binary pulsar
observed and theory was used to find an error in the computer algebra
program that generates the series to compute the gravitational
potential in the solar system.

Regards,
Martin Brown

"Martin Brown" wrote in message
oups.com...
On Feb 22, 5:11 am, "TMA" wrote:
http://www.space.com/scienceastronom...ts_030407.html

Looking for gravity waves is like looking for ET's it seems. If these
waves
aren't detected within 20 years
it will be a huge blow to relativity.

Hardly.

It is much more likely that the experimentalists cannot reach the
sensitivity needed to distinguish gravity waves from thermal noise on
that timescale. GR will live on until such time as a major
gravitational event occurs close enough that it should be detected but
was not. The signals they are looking for are unbelievably feeble.

My guess is when they get the experiment sensitive enough they will
see them. The behaviour of binary pulsars is exactly in line with what
GR predicts. In fact it was so precisely in line with what GR
predicted that the discreprancies between the first binary pulsar
observed and theory was used to find an error in the computer algebra
program that generates the series to compute the gravitational
potential in the solar system.

Regards,
Martin Brown


Yes, just like looking for ET's!

On Feb 21, 9:11 pm, "TMA" wrote:
http://www.space.com/scienceastronom...ts_030407.html

Looking for gravity waves is like looking for ET's it seems. If these waves
aren't detected within 20 years
it will be a huge blow to relativity.

The above article is 4 years old. I went to a talk by one of the LIGO
scientists last month, and it would seem that LIGO is now operational
at Phase I. This puts it right on the edge of being able to detect
fairly rare events. Phase II should greatly improve the sensitivity,
and there's also a Phase III, IIRC. However, I wouldn't hold your
breath waiting. It could be years before they detect something.

LISA, OTOH, will be much more sensitive, but is still a decade off, if
the politicians don't kill it off in order to get another jock to the
moon.

PJR