Two event horizons in close proximity

  • Thread starter kurious
  • Start date
In summary, when two black holes of equal mass move together and their event horizons meet, photons do not orbit at the event horizon but instead unstably orbit at the photon sphere. In the case of ideal Schwarzschild black holes, the photon sphere is at a specific radius.
  • #1
kurious
641
0
Two black holes of equal mass move together so their event horizons meet.
How would a photon initially going around one horizon in a circle,know which horizon to go around when it comes to the place where the horizons meet?
And if there were thousands of small black holes filling a large area of space, all with touching event horizons, how would the photon behave?
 
Physics news on Phys.org
  • #2
kurious said:
Two black holes of equal mass move together so their event horizons meet.
How would a photon initially going around one horizon in a circle,know which horizon to go around when it comes to the place where the horizons meet?
And if there were thousands of small black holes filling a large area of space, all with touching event horizons, how would the photon behave?

Photons don't orbit at the event horizon. They unstably orbit at the Photon sphere.
 
  • #3
When two black holes meet, they would most likely collapse into one. Similarly with lots of black holes touching.
 
  • #4
DW said:
Photons don't orbit at the event horizon. They unstably orbit at the Photon sphere.

Can the orbit be stable in an idealized Schwarzschild black hole?
 
  • #5
jcsd said:
Can the orbit be stable in an idealized Schwarzschild black hole?

No, that's actually the kind of hole I was referring to. For the ideal Schwarzschild hole the photon sphere is at
[tex]r_{ps} = \frac{3GM}{c^2}[/tex].
 

1. What are event horizons?

Event horizons are boundaries around a black hole or other massive object where the gravitational pull is so strong that nothing, including light, can escape. This creates a point of no return, where anything that crosses the event horizon is pulled into the object's singularity.

2. How is an event horizon formed?

An event horizon is formed when a massive object, such as a black hole, has a strong enough gravitational pull to bend space and time. This creates a region where the escape velocity is greater than the speed of light, making it impossible for anything to escape.

3. What is the significance of two event horizons in close proximity?

Two event horizons in close proximity can occur when two black holes are in a binary system, orbiting each other. This can have significant effects on the surrounding space, such as the emission of gravitational waves, and can also lead to the merging of the black holes.

4. How do two event horizons affect the behavior of matter and energy?

The presence of two event horizons in close proximity can cause a phenomenon known as the "innermost stable circular orbit" (ISCO). This is the closest distance that matter or energy particles can orbit around the black holes without being pulled into the event horizons. The ISCO can also cause the accretion disk of matter around the black holes to become unstable and emit bursts of radiation.

5. Can two event horizons merge?

Yes, two event horizons can merge through a process known as black hole coalescence. This occurs when two black holes in a binary system merge together, resulting in a single black hole with a larger event horizon. This process is thought to be responsible for some of the most energetic events in the universe, such as the emission of gravitational waves.

Similar threads

I Do any real macroscopic black holes have a singularity?
    • Special and General Relativity
Replies
11
Views
694
B Entering a black hole -- I know I must be wrong (Help me understand why)
    • Special and General Relativity
Replies
29
Views
287
I Time Dilation Near a Black Hole: Accelerating Objects Approaching the Event Horizon
    • Special and General Relativity
2
Replies
35
Views
1K
B Crossing the Bekenstein Bound at Black Hole Event Horizon
    • Special and General Relativity
Replies
8
Views
939
I Black Holes: Event Horizon Causally Disconnected?
    • Special and General Relativity
Replies
21
Views
2K
B Exploring Time and Space Dilatation Near Black Hole Event Horizon
    • Special and General Relativity
Replies
3
Views
1K
B Black Holes: How Do They Move?
    • Special and General Relativity
Replies
22
Views
2K
B Can we see 2 black holes orbiting each other?
    • Special and General Relativity
2
Replies
57
Views
1K
B Physics near the event horizon
    • Special and General Relativity
2
Replies
39
Views
3K
I Gravity at Schwarzschild Radius of a Black Hole
    • Special and General Relativity
Replies
17
Views
2K

Hot Threads

Recent Insights

Back
Top