Evidence for gravitational waves

[coldcreation]

...however, resonance patterns within gravitational systems are well known. Those are similar to waves in that there are hills and valleys, some stable (L4, L5) others unstable (L1, L2 and L3). I wouldn't call those waves though...

[BlameTheEx]

Originally Posted by coldcreation

Gravitational wave, as we write are not a proven phenomenon.

Yes, a few observations agree with Einstein's prediction. That is no surprise.

What is a surprise is that gravitational wave detectors (similarly, neutrino detectors) have found no conclusive evidence beyond the margine of error.

I'm trying to say that gravity is not necessarily something that propagates like photons, of waves on the surface of the ocean. (Note that a graviton has never been observed)

If it is not something that propagates, then there is no such thing as G waves.

Hmm. I could point out that there is no such thing as proof, if defined as absolute proof. All there is evidence.

The binary pulsars provided evidence which Einstein's theory predicted and explained. That is a major blow to any alternative theory that doesn't also explain this evidence. It may explain it in a completely different way but explain it it must or be seriously weakend.

As for the gravity wave detectors - what is it they didn't detect? To use them as more than the most limited of refutals you must show the strength of evidence for astronomical events that should have been detected. Gravity waves strong enough and local enough to be detected by these devices may just be very rare.

[coldcreation]

Originally Posted by BlameTheEx

Hmm. I could point out that there is no such thing as proof, if defined as absolute proof. All there is evidence.

The binary pulsars provided evidence which Einstein's theory predicted and explained. That is a major blow to any alternative theory that doesn't also explain this evidence. It may explain it in a completely different way but explain it it must or be seriously weakend.

As for the gravity wave detectors - what is it they didn't detect? To use them as more than the most limited of refutals you must show the strength of evidence for astronomical events that should have been detected. Gravity waves strong enough and local enough to be detected by these devices may just be very rare.

Very astute BlameTheEx, evidence, not proof. Therefore interpretations are to be made rather than assertions. Any assertions have to be based on fundamental laws of nature. If there are non to back specific claims, then the claims rests as speculative. Not that anything is wrong with speculation. But they remain just that. Note that what is called new physics is often solely of speculative origin.

If GR was considered ‘new physics’ at the time of its inception, it is very different from the ‘new physics’ involved in superstring and inflationary theory. Einstein’s stance was straightforward:

“Turning to the theory of relativity itself, I am anxious to draw attention to the fact that this theory is not speculative in origin; it owes its invention entirely to the desire to make physical theory fit observed fact as well as possible.... The abandonment of certain notions connected with space, time, and motion hitherto treated as fundamentals must not be regarded as arbitrary, but only as conditioned by observed facts.” (Einstein 1921, see 1954). [GR is a class of “principle-theories” as its inventor called them.] “These employ the analytic, not the synthetic, method. The elements which form their basis and starting-point are not hypothetically constructed but empirically discovered ones, general characteristics of natural processes, principles that give rise to mathematically formulated criteria…” (1919, see 1954). “If the basis of theoretical physics cannot be an inference from experience, but must be a free invention, have we any right to hope that we shall find the correct way? Still more—does this correct approach exist at all, save in our imaginations? To this I answer with complete assurance, that in my opinion there is a correct path. Moreover, that it is in our power to find it.” (Albert Einstein 1919, see Ideas and Opinions 1954, 1982, Three Rivers Press, New York).

I agree...

Gravitational waves are just one predicted feature of a theory with implications in all branches of physics (cosmology, etc.). Some of those implication remain obscure to date. Notably the implications regarding the cosmological constant...

Something has only just begun

A.M. Coldcreation

[maddog]

The notion of Gravitational Wave is the elegant duality like light in QM expressed for
Gravity. Both a particle and a wave. No current qualified valid evidence yet exists
for either GW or the Graviton. Yet some form of a field exists in the theoretically
Gravity can be defined as a valid according QFT. Yes, we don't detect these critters
yet. Doesn't mean they are not present. We now have evidence for Dark Matter
and we don't know why. It is true that in every String Theory worked out to date
(that have heard of), the spin-2 particle (thought to be a graviton) is present.
Interesting.

maddog