General Relativity question involving Metrics

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Homework Help Overview

The discussion revolves around a problem in general relativity involving a specific metric and its implications for gravitational redshift, effective potentials, and light cones. Participants are exploring various aspects of the metric and its physical interpretations.

Discussion Character

  • Exploratory, Conceptual clarification, Problem interpretation

Approaches and Questions Raised

  • Participants are attempting to calculate the gravitational redshift and are discussing their results, with some expressing uncertainty about their findings. Questions about the effective potentials for massive and massless particles are raised, along with interpretations of stability and behavior near r = 0. There is also a query regarding the asymptotic nature of curves related to the gravitational redshift.

Discussion Status

The discussion is ongoing, with participants sharing their attempts and questioning the clarity of the problem. Some guidance is being offered informally, but there is no explicit consensus on the approaches or interpretations yet.

Contextual Notes

Participants note the vagueness of certain aspects of the problem, particularly regarding the effective potentials and the behavior of particles in the given metric. There is an acknowledgment of the complexity involved in interpreting the results.

Auburnman
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Homework Statement



(30 points) Consider the metric
ds^2 = -(1 -(r^2/R^2))dt^2 + (1-(r^2/R^2))^-1 dr^2 + (r^2)d(omega)^2

Note that spacetime becomes
at at small r, not large r. r < R.
(a) Calculate the (exact) gravitational redshift (w_2)/(w_1) between two stationary ob-
servers at radial coordinates r1 and r2 and the same angular coordinates.
Discuss interesting limiting cases.

(b) Calculate and sketch the eff ective potentials V (r) for the radial motion of particles,
for the cases of massive and massless particles.
Interpret this e ffective potential: are there stable orbits? Are particles attracted
to r = 0? Can particles reach r = 0?
(c) Draw some light cones. Comparing your plot to that for the Schwartzschild
metric, what appears to be happening at r = R?

Homework Equations


Schwartzchild metric, and the given metric

The Attempt at a Solution


for the first part i got (w2/w1) = [1-(r1^2/R^2)]^.5 / [1-(r2^2/R^2)]^.5 but i don't think this is correct please help!
 
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I got the same thing for part (a). Number 4 is whack man!
 
you know how 2 do 4b? because if i get that i can get the rest of problem 4
 
I have an idea but haven't worked it out. The question just seems so vague that I'm not even sure if I'm on the right track. Is your curve for part (a) asymptotic?
 
yes, what did u get for the true false questions?
 
lol who is this?
 
does that matter?
 
is there some other median besides this that you would like to talk about the problems or u going to work on it alone?
 

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