Transformations in curved spacetime?

wpan
Messages
4
Reaction score
0
I know that the spacetime in special relativity is not curved and that the axis can be transformed via the lorentz transformations.

I was wondering if the curved spacetime in general relativity can be transformed in such a way, and if so, how?
 
Physics news on Phys.org
Yes of course. The Lorentz transformations are the set of transformations that preserve the space-time interval $$ ds^2 = dt^2 - dx^2 - dy^2 - dz^2 $$. A similar concept of space-time interval also applies to GR.
 
Depends on just what you mean, but generally, 'no'.

Wikipedia puts it this way: [Minkowski space is the the flat space-time of SR]
http://en.wikipedia.org/wiki/Lorentz_transformation

In Minkowski space, the Lorentz transformations preserve the spacetime interval between any two events. They describe only the transformations in which the spacetime event at the origin is left fixed, so they can be considered as a hyperbolic rotation of Minkowski space...
In the flat spacetime of SR the space-time separation between two events or two observers is the integral of ds along a straight line from one event to the other. [There is only one such straight line.] The analogous measure in curved spacetime would be the integral of ds along a geodesic [free fall path], generally a curved worldine. But in general in curved spacetime there are multiple geodesics connecting the events so you won't see much talk of “space-time separation” in GR because there are many such paths.
 
Last edited:
OK, so this has bugged me for a while about the equivalence principle and the black hole information paradox. If black holes "evaporate" via Hawking radiation, then they cannot exist forever. So, from my external perspective, watching the person fall in, they slow down, freeze, and redshift to "nothing," but never cross the event horizon. Does the equivalence principle say my perspective is valid? If it does, is it possible that that person really never crossed the event horizon? The...
In this video I can see a person walking around lines of curvature on a sphere with an arrow strapped to his waist. His task is to keep the arrow pointed in the same direction How does he do this ? Does he use a reference point like the stars? (that only move very slowly) If that is how he keeps the arrow pointing in the same direction, is that equivalent to saying that he orients the arrow wrt the 3d space that the sphere is embedded in? So ,although one refers to intrinsic curvature...
So, to calculate a proper time of a worldline in SR using an inertial frame is quite easy. But I struggled a bit using a "rotating frame metric" and now I'm not sure whether I'll do it right. Couls someone point me in the right direction? "What have you tried?" Well, trying to help truly absolute layppl with some variation of a "Circular Twin Paradox" not using an inertial frame of reference for whatevere reason. I thought it would be a bit of a challenge so I made a derivation or...
Back
Top