Can black holes be disintegrated from a sufficiently powerful explosion?

Bararontok

Is it possible for another black hole with an axis of rotation parallel to the first black hole and spinning in the same direction as the first black hole transfer some of its rotational energy through its gravitational field to the first black hole and make it spin faster? Would it also make it easier for the second black hole to do this if it is larger than the first black hole?

PoeMeson

But if you're sucking up all the hawking radiation you are depriving the black hole of what it needs to evaporate.

FOIWATER

Isn't the hawking radiation WHAT is evaporates

Not a necessity TO evaporate

PAllen

The fastest a black hole can evaporate is in absolute zero degree 'empty space', which is what most figures for evaporation rates assume. That is, quoted evaporation times already assume the fastest possible conditions. For stellar black holes, there will be net growth due to CMB being 'hotter' than their Hawking temperature until the heat death of the universe. And for small black holes (if they exist), the CMB is indistinguishable from absolute zero, so there is no further speed up possible. Certainly, there is no way for evaporation to proceed faster than the normally quoted figures, for any black hole.

twofish-quant

Not convinced.

Temperature differences give you the direction of the energy flow. The speed at which an object cools depends on the detailed physics. If the calculations are assuming ordinary radiative processes from the black hole into empty space, then those aren't obviously fundamental thermodynamic limits.

I'll have to look at the derivation to be convinced.

You have a black hole at temperature T_BH and you put that into empty space which we assume is at zero K. If the calculations assume that the black hole is just radiating into cold space, then simple radiation not the fasting possible rate of cooling.

If there's another thermodynamic constraint then that's different.

twofish-quant

Another question. How do black holes interact with cosmological constants. Suppose there is a "big rip" what happens to black holes?

PAllen

What non-radiative process might you propose? For normal matter, most everything else boils down to collisions (potentially augmented by fluid flow, but the microscopic transfer is still a collision). Collision with a black hole will simply grow the hole.

So, yes, I am assuming there is no alternative process.

twofish-quant

Give me some time and I think of something.

Bit you aren't interacting with the black hole, you are interacting with the radiation field around the black hole. You put a black hole with temperature T in empty space with zero temperature. The black hole will radiate empty space with a temperature gradient. Now we put in a refrigerator at temperature less than the temperature gradient. What happens?

So the question here is can you come up with physics argument why there can't be an alternative process?

Drakkith

Twofish, I understand that closer to the black hole you would have more radiation, but how does somehow taking a section of space near the BH and removing the radiation increase the rate at which the BH radiates? Doesn't it simply depend on the amount of radiation falling on the BH compared to the amount of radiation being emitted?

twofish-quant

Still working it out, but it looks promising.

The situation is that it appears that the derivation of the Hawking-Unruh equations assumes that some fraction of the radiation that gets produces just outside of the black hole, falls back into the black hole. Now if you can somehow capture some of the the "fallback" radiation then that would increase the leakage from the black hole.

What I'm trying to figure out now is the maximum radiation that you can get if you prevent "fallback."

Drakkith

Just how far from the event horizon is the radiation produced at? I'm assuming it is created at various distances, with less being produced at increasing distance from the EH, although I don't really have any idea.

Naty1

According to Wikipedia the Stefan–Boltzmann-Schwarzschild-Hawking power law has
nothing to do with exterior temperatures.


http://en.wikipedia.org/wiki/Hawking...le_evaporation


Power loss P is hc⁶/15360[pi]G²M²

Spinalcold

Wouldn't a faster spinning black hole evaporate SLIGHTLY faster due to hawking radiation getting caught up in the polar jets? I could he wrong but I thought faster spinning black holes have larger jets which help the accretion disk slow enough so more particles can be absorbed. The same process could help to throw away hawking radiation so that less of it was reabsorbed.

mrspeedybob

I vaguely remember a pop-sci bit a while back talking about creating baby universes in a lab by pinching off bits of space which would then be separate from our universe and expand in their own big bang. Something like this http://www.npr.org/templates/story/s...toryId=6545246

I have no idea what the details are but someone more familiar with this idea might chime in. Would it be possible to pinch off a volume of space containing a black hole so that the black hole no longer exists in out universe, but in its own new universe? It may not technically be disintegration as the OP was asking about the effect is the same, the BH no longer exists, at least in our universe.

stevebd1

According to a number of sources, spinning (and charge) actually reduces HR though for it to reduce significantly, the black hole would have to be very near maximal (i.e. a/M=1).

One source-
http://edoc.ub.uni-muenchen.de/6024/1/Deeg_Dorothea.pdf

iced199

Even if you could somehow blow apart a black hole, which seems impossible because trying to do so would just make the black hole larger, it would break into smaller black holes, which could merge back into the original. Nothing changed.

jarroe

what effect would a supernova blast have if it were within a light year distance of a black hole? we shall never know but the math i'm sure would boil it down to the dreadful singulairity!!!!!!