Gravity at the speed of light - Help needed.

[Robittybob1]

 

 

It means we don't experimentally observe any (or only a small amount) of aberration. Not because it's absent, but because there are other effects which cancel it.

So is that covering this situation?

"Then, if the infall could take forever to allow us time to take the LIGO further and further away from the BBH but staying on the angular momentum vector, this toing and froing should continue but the amplitude will diminish. The alignment will depend on the speed/directness of gravity (can we draw straight lines or are they curves or whatever). The speed of gravity seems to be the difficult question for if gravity had to take a spiral path would light have to do the same?"

In reality they were orbiting for at least a billion years, so when they estimate the distance back to the BBH is it a straight line or a spiral? I'm wrong for all the spiraling has finished now, it was only spiralling prior to the merger and we couldn't estimate its distance till the merger.

If you can take most of the aberration effects away the line becomes straighter but not dead straight.

[Robittybob1]

Today after several days of being confounded by the speed of gravity issues I'm coming around to thinking light and gravity have the same path between A & B, the gravity strength is the one from the position you see a mass.

This means no matter how tortuous the spacetime is warped between those two points gravity and light will always be in phase.

 

Now this seems like a weird thought but can anyone find the fault in that. I did read something about this recently (I'll see if I can find confirmation of this).

 

"http://math.ucr.edu/home/baez/physics/Relativity/GR/grav_speed.html""Does Gravity Travel at the Speed of Light?" explains it quite well and introduce the idea of gravitational radiation due to the not quite cancelled "velocity terms".

This article https://medium.com/starts-with-a-bang/what-is-the-speed-of-gravity-8ada2eb08430#.1lb1mj5ya "What is the Speed of Gravity?" It is weird gravity proven to travel at the speed of light but the problems that this would cause is cancelled out (so gravity behaves as if it is nearly instantaneous) except where the mass accelerates (is in orbit).

So the sun disappearing trick should be: we see the light for another 8 minutes but gravity is gone immediately (but no one says that either so I still don't get it!)

Edited March 18, 2016 by Robittybob1

[Mordred]

The difficulty lies in multiple theories. One of the hazards of online vs textbook studies.

 

Word of advise treat Gravity as the same as light except quadrupole(spin2) vs dipolar(spin 1) statistics.

 

(Treat the graviton as massless, identical to photons except spin polarization)

 

Any good theory will have competition.

Its not my goal to persuade One side or another. My goal is to teach the the fundamentals to well informed decision

Edited March 18, 2016 by Mordred

[Robittybob1]

 

 

It means we don't experimentally observe any (or only a small amount) of aberration. Not because it's absent, but because there are other effects which cancel it.

If anyone sees information on this could they post it on the forum please.