If two black holes with equal mass and angular momentum, but the latter in opposite directions were to collide, they would release a great deal of radiation and would subsequently lose energy and the resulting black hole would have a lower total mass than the two previous ones combined.(adsbygoogle = window.adsbygoogle || []).push({}); But how can I calculate how much of their combined original mass would (at most) be released as radiation in the collision?

I know I should start from the "area-theorem". Unable to find it in my coursebook, I looked it up on wikipedia.

Hawking's Area theorem:

[tex]A_H=\frac{4\pi G^2}{c^4}((M + \sqrt{M^2-a^2})^2+a^2)[/tex]

- This being the area of the eventhorizon of the black hole.

Is there some relation between the areas the two original black holes and the subsequently combined black hole?

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Colliding rotating black holes

**Physics Forums | Science Articles, Homework Help, Discussion**