A Does anyone know asymmetric dynamic global solutions to Einstein eqs?

Heikki Tuuri
Messages
164
Reaction score
64
https://link.springer.com/article/10.12942/lrr-2005-6

https://en.wikipedia.org/wiki/Exact_solutions_in_general_relativity

http://www.numdam.org/article/SEDP_1989-1990____A15_0.pdf

A moderator removed this off-topic discussion from another thread. Does anyone on the Physics Forums have expertise on the existence of global solutions of general relativity?

As you see, people have worked very hard for 104 years to prove existence theorems. As far as I know, they are all limited to small perturbations of highly symmetric solutions.

Can anyone point to research that might have progressed closer to realistic physical configurations?
 
Physics news on Phys.org
Heikki Tuuri said:
Can anyone point to research that might have progressed closer to realistic physical configurations?
Part of the problem (the main problem) was your personal and overly restrictive view of what constituted a realistic physical configuration. For example, you objected to the FLRW solution as being unrealistic whereas most scientists and particularly cosmologists consider it realistic.
 
Heikki Tuuri said:
As you see, people have worked very hard for 104 years to prove existence theorems. As far as I know, they are all limited to small perturbations of highly symmetric solutions.
That is not true. Global existence (as in the maximal hyperbolic Cauchy development) is a result from 1969 (Choquet-Bruhat, Geroch). What is limited is the understanding of those solutions.
Can anyone point to research that might have progressed closer to realistic physical configurations?
What do you mean by realistic physical configuration?
 
Heikki Tuuri said:
A moderator removed this off-topic discussion from another thread.

Which is completely irrelevant to this thread. Please do not carry over whatever issue you might have with the moderators in a previous thread to new threads.
 
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

Back
Top