This is a good introduction: http://math.ucr.edu/home/baez/einstein/

 

 

No, that isn't what was said at all. The Shapiro time delay is a consequence of GR. That is why you can't solve the equations and then add in an extra delay.

Extra help Shapiro delay is already included....

 

This is a good introduction: http://math.ucr.edu/home/baez/einstein/

 

 

No, that isn't what was said at all. The Shapiro time delay is a consequence of GR. That is why you can't solve the equations and then add in an extra delay.

Thanks both of you for those valuable links. Should keep me busy for a while!

I can't see how you could treat them seperate

Indeed... so again for the benefit of all, gravitational waves come from linearising the Einstein field equations. You think of a 'total metric' as the sum of a background metric and a small perturbation.

 

g = g0 + h

 

The perturbation h can then be shown, with some work, that it satisfies the wave equation. Thus, as it stands, it is not clear how one could really treat gravitational waves and the metric as being completely separate things.

 

The only hope that I see is that one could include some separate field and construct it so that all the predictions of observable effects of gravitational waves are described using this extra field. I have no idea if anyone has tried to do this, or how successful this idea is. Nor am I sure that it is well motivated.

Thanks both of you for those valuable links. Should keep me busy for a while!

 

And quiet, hopefully. (Just kidding)

The only hope that I see is that one could include some separate field and construct it so that all the predictions of observable effects of gravitational waves are described using this extra field. I have no idea if anyone has tried to do this, or how successful this idea is. Nor am I sure that it is well motivated.

 

Sounds a little reminiscent of Brans-Dicke theory (but that is way over my head)

 

This is a good introduction: http://math.ucr.edu/home/baez/einstein/

 

 

No, that isn't what was said at all. The Shapiro time delay is a consequence of GR. That is why you can't solve the equations and then add in an extra delay.

As I said I'm not that great with those thoughts as yet, so your reasoning could be correct but to me it feels like "forbidden" ("can't" and "forbidden" are similar) for want of a better word. It was only a word that has come from me, from my misunderstanding, I never said I was quoting anyone.

The difficulty in most model systems is defining the system from other models. Took me years to learn that...

 

Wish there was a simple answer but you must study each metric at all definitions.

 

Lol welcome to science, where every viable explanation is possible till shown not viable. (and there is always viable counter explanations)

Edited March 18, 20169 yr by Mordred