Black hole collapse - ray tracing

Click For Summary
SUMMARY

This discussion focuses on the lack of reliable ray tracing results for collapsing black hole models, specifically the Oppenheimer-Snyder and Vaidya metrics. Participants explore the relationship between ray tracing and null geodesics, asserting that the static Schwarzschild metric behaves similarly to the Oppenheimer-Snyder model under specific conditions. The conversation highlights the importance of simulated images in understanding light behavior near black holes, particularly in relation to the event horizon of Sagittarius A*.

PREREQUISITES
  • Understanding of ray tracing in general relativity
  • Familiarity with the Schwarzschild and Vaidya metrics
  • Knowledge of null geodesics and their significance in black hole physics
  • Basic concepts of light behavior in gravitational fields
NEXT STEPS
  • Research the Vaidya metric and its implications for light behavior in collapsing black holes
  • Explore simulated images of black holes, particularly focusing on Sagittarius A*
  • Study the relationship between null geodesics and ray tracing in general relativity
  • Investigate the feasibility of resolving event horizons using infrared observations
USEFUL FOR

Astronomers, physicists, and researchers interested in black hole dynamics, ray tracing techniques, and the observational challenges of studying black holes.

tom.stoer
Science Advisor
Messages
5,774
Reaction score
174
I know several raytraycing results for static Schwarzschild black holes, but I have never seen something similar for collapse models like Oppenheimer-Snyder or Vaidya.

Are there reliable raytraycing results showing the effect on light rays from far distant light emitters observed by (far distant) observers?
 
Physics news on Phys.org
no ideas?
 
push
 
What do you mean by raytracing results? Mathematical theorems? Simulated images? Characterizations of possible orbits? The Vaidya metric represents the collapse of a field of incoherent radiation, so I would think that the geodesics would be the same as the trajectories of the infalling matter, which would also be the same as the rays in an optical simulation.

Is this of any interest? Seahra, "An introduction to black holes," http://www.math.unb.ca/~seahra/resources/notes/black_holes.pdf Has a bunch of discussion of horizons in the Vaidya metric.
 
Assuming I'm right in thinking that ray tracing is just null geodesics, the static schwarzschild should be the same as oppenheimer-snyder if you make sure light only passes in the external part of the metric, as the metric is the same.

I'm guessing this may not be particularly helpful, though.
 
Last edited:
pervect said:
Assuming I'm right in thinking that ray tracing is just null geodesics, the static schwarzschild should be the same as oppenheimer-snyder if you make sure light only passes in the external part of the metric, as the metric is the same.
Yes.

The Schwarzschild portion is growing with t to smaller r(t), therefore the images of rays not crossing r(t) are rays like in Schwarzschild spacetime with smaller r(t) but constant mass M.

But what I am especially interested in is the image of rays
a) passing through the dust ball (assuming that the dust is transparent)
b) close to r(t) in the far future where r(t) → 2M asymptotically
 
So realistic simulations of what might be seen through a telescope? I think the studies so far have been studies of the feasibility of resolving the event horizon of Sag A* using infrared. I would be surprised if anyone had tried simulating anything else, because Sag A* is the only realistic prospect for us to resolve.
 

Similar threads

Insights Oppenheimer-Snyder Model: Overview of Gravitational Collapse
  • · Replies 5 ·
Replies
5
Views
3K
High School How can a black hole absorb matter?
  • · Replies 31 ·
2
Replies
31
Views
2K
Undergrad Black hole formation and infinite redshift
  • · Replies 8 ·
Replies
8
Views
2K
Graduate Do Black Holes have Singularities?
  • · Replies 20 ·
Replies
20
Views
3K
Undergrad Black hole horizon for different observers
  • · Replies 24 ·
Replies
24
Views
3K
Undergrad Do any real macroscopic black holes have a singularity?
  • · Replies 11 ·
Replies
11
Views
2K
Undergrad Evaporating black hole: First principles consideration
  • · Replies 1 ·
Replies
1
Views
1K
Undergrad You can't actually enter a blackhole?
  • · Replies 40 ·
2
Replies
40
Views
3K
Undergrad Observing a Collapsing Shell: Time Dilation Explained
  • · Replies 2 ·
Replies
2
Views
2K
High School How do Black Holes Grow? A Far-Away Observer's Perspective
  • · Replies 67 ·
3
Replies
67
Views
6K