Question on Phenomena beyond General Relativity

Harry Wang
Messages
2
Reaction score
0
Hello, I'm Harry.
I'm new here, hope not breaking any posting rules in any ways :)

I have a question and would like to ask for some suggestions and information.
The question is about general relativity or gravity and structure of the Universe in general; I know there are definitely quite a few phenomenons that is beyond GR's explanation, however I'm specially curious about singularities in spacetime from the research projects I'm currently under.

Due to GR's dependence on manifold, there's seems to be not much freedom to talk about singularities. Yet there probably are phenomenons beyond black holes that are also singularities, however I don't know their names and corresponding theories due to lack of background knowledge, leading me asking for a favor, if there is such phenomenon could you name it for me? And if you know the corresponding theory, would you also name it for me?

I would make further research on my own because I don't want to sound like a lazy douche :P
However I need some help on the keywords and direction which I should look for, so it would be wonderful if someone would give me some hints on these. Thanks a lot!

Your, truly
 
Physics news on Phys.org
Singularities are not phenomena "beyond general relativity." They are a standard prediction of GR. The fact that GR doesn't describe a singularity as a point-set doesn't mean that GR can't talk about them. It can.

Black hole singularities are not the only type of singularity in GR, or even the only type we observe in our universe. The big bang was a singularity. Naked singularities (cf. timelike singularities) are the subject of the cosmic censorship hypothesis. GR also allows non-curvature singularities, such as the ones that occur in some Taub-NUT spacetimes.
 
  • Like
Likes Harry Wang
bcrowell said:
Singularities are not phenomena "beyond general relativity." They are a standard prediction of GR. The fact that GR doesn't describe a singularity as a point-set doesn't mean that GR can't talk about them. It can.

Black hole singularities are not the only type of singularity in GR, or even the only type we observe in our universe. The big bang was a singularity. Naked singularities (cf. timelike singularities) are the subject of the cosmic censorship hypothesis. GR also allows non-curvature singularities, such as the ones that occur in some Taub-NUT spacetimes.
Thank you sir bcrowell ! And thanks for putting up my naive words due to lacking of GR knowledge:P
 
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...
ASSUMPTIONS 1. Two identical clocks A and B in the same inertial frame are stationary relative to each other a fixed distance L apart. Time passes at the same rate for both. 2. Both clocks are able to send/receive light signals and to write/read the send/receive times into signals. 3. The speed of light is anisotropic. METHOD 1. At time t[A1] and time t[B1], clock A sends a light signal to clock B. The clock B time is unknown to A. 2. Clock B receives the signal from A at time t[B2] and...

Similar threads

Replies
118
Views
10K
Replies
17
Views
3K
Replies
2
Views
2K
Replies
12
Views
2K
Replies
2
Views
2K
Replies
8
Views
2K
Replies
12
Views
3K
Back
Top