# Black hole evaporation, where does it all go?

1. May 6, 2013

### Geordie Ross

I hear that black holes evaporate, but does it all get converted into Hawkins radiation? And what role do white holes play in evaporation?

2. May 6, 2013

### Staff: Mentor

Hawking.
Probably yes, but a theory of quantum gravity is needed to study that in detail. As the black hole gets hotter and hotter, it begins to emit heavier particles, in addition to the photons.
There are no indications that white holes exist.

3. May 6, 2013

### Geordie Ross

Thanks, and is it true that the smaller the black hole, the faster it evaporates? And is there a critical mass that prevents super massive black holes from evaporating?

4. May 6, 2013

### bapowell

Yes, smaller black holes radiate at higher temperatures. The Hawking temperature is directly proportional to the surface gravity, $\kappa$, of the object, $T = \kappa/2\pi$. As the black hole shrinks, its surface gravity goes up (proportional to $1/R^2_S$, where $R_S$ the Schwarzschild radius) and, hence, so does its temperature.

There is no critical mass that prevents black holes from evaporating.

5. May 6, 2013

### Geordie Ross

Thank you for the detailed replies, my curiosity is temporarily quenched!