# Two event horizons in close proximity

1. Jun 30, 2004

### kurious

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?

2. Jun 30, 2004

### DW

Photons don't orbit at the event horizon. They unstably orbit at the Photon sphere.

3. Jun 30, 2004

### mathman

When two black holes meet, they would most likely collapse into one. Similarly with lots of black holes touching.

4. Jun 30, 2004

### jcsd

Can the orbit be stable in an idealized Schwarzchild black hole?

5. Jun 30, 2004

### DW

No, thats actually the kind of hole I was referring to. For the ideal Schwarzschild hole the photon sphere is at
$$r_{ps} = \frac{3GM}{c^2}$$.