Recent content by Berislav

Odd. I never thought Bush was into SM.

No, they would evaporate very quickly. They were likely talking about strangelets.

Let's attack the UN! o:)

Yey! http://www.nationstates.net/cgi-bin/index.cgi/target=display_nation/nation=tensor_analysis

g_{00}=c^2 \left( 1-\frac{2GM}{c^2 r} \right) As you can see the metric blows up in that limit. This is because time has no geometric structure, or meaning as such, in Newtonian physics. No, it blows up. No, it doesn't. That's called gauge fixing. Which doesn't have anything to do with...

Yes, my mistake. The appearance of the metric tricked me. I should have checked the curvature 2-form before I said anything.

Are you sure that the Riemann tensor of this metric is zero? In my previous post I used: ds^2=-dt^2+R^2(t) (\frac{dr^2}{1-kr^2}+r^2d\Omega^2) There still is a coefficient multiplying dr^2. I think one should say that it isn't physical as R (or a, in your notation) will become negative...

I'll attempt to fill in for pervect in the mean time. :smile: The Robertson-Walker metric is derived by assuming homogenity and isotropy (nothing else about the content of the universe): ds^2=-dt^2+R^2(t) (\frac{dr^2}{1-kr^2}+r^2d\Omega^2), where k can be anything, but we can redefine...

I didn't mention that spacetime because I never heard about it. :redface: I apologize. :frown:

Please check the metric again. You will see that that is not what happens to it. And I think that Wald didn't take that limit because he dealt with SR and Newtonian approximations in one of the previous chapters, so he assumed that the reader understands that that is how one reduces to Newtonian...

I am not sure, but I think that if spacetime is approximately flat then gravity is negligable. Also, there is a problem with the fact that Newton's physics has no underlaying geometric structure (i.e, it is not a flat spacetime). If you mean if the spacetime is asymptotically flat then most...

Yes. Because of the principle of equivalence.

Here's a wikipedia article about it: http://en.wikipedia.org/wiki/Hodge_star_operator I heard that the first reference is often called the 'Bible of GR'.

No. That's not how one would do it. The spacetime wouldn't static anymore. One would for one have to use this metric (provided by pervect and robphy): https://www.physicsforums.com/showthread.php?t=88883 because instantaneous propagation of matter of the source of gravity would lead to a...

I'm sorry. I didn't have time to respond to your entire post at once. Proper time is Newtonian time. Time as a coordinate is non-Newtonian. I don't have that and I'm not sure how one would make such a mapping. But what about Wald p. 138, 139? The effective potential equation (6.3.15) is a...