Is the surface of a Black Hole hot or cold?

Question

Try give an explanation for your answer. Serious or funny, it matters not, so long as the answers are about the singularity dot!

Answer 1

By definition black holes are dots thus have no surfaces thus no temperatures but they are also infinite holes therefore you could go through them...contradiction, well thats what black holes are all about. My theory is that they are both hot and cold. In the initial segments of the the hole it will be very hot as everything is being sucked in...in the lower segments of this hole, when everything has lost practically all energy, things would start to cool down...to what I think close to the perfect zero temp.

Answer 2

Black holes DO have a surface. What makes them black is the intense gravity and what makes them holes is that everything 'falls' into it. That said, the surface of a black hole would be cold. The compression needed to stop atomic movement would eliminate heat (I'm thinking), however there would be some release of energy (gamma rays) that would heat up any surface approaching the 'hole'. so, it might FEEL hot, but in actuality, it would be cold.

Ask Stephen Hawking, he seems to spend a lot of time pondering this.

Answer 3

Well just outside the blackhole it is extremely hot due to the pressure increase and amazing acceleration around the point. This has been somewhat proven.

As for the blackhole itself or the "surface" of the event horizon, I would have to muse that it is actually eventually quite cold because at some point the matter would not exist or move as matter anymore and this would suggest that the temperature is absolute zero (or perhaps it infinately approaches that??). The heat outside the blackhole however should be causing things to expand.

Answer 4

This question relates to one of Stephen Hawking's most famous theoretical papers, from around 1974. In that paper, he considers black holes in a vacuum, enclosed in a box with reflecting walls. He argues that the "surface" of the black hole, the event horizon, must emit particles with a characteristic temperature. The mechanism, roughly speaking, is that virtual particle pairs occurring spontaneously in the vacuum are separated by the gavitational tide of the black hole, one virtual particle goes into the hole and the other escapes into the box. The box fills with radiation, and eventually the process comes into equilibrium, where the production of particles is balanced by the absorption of particles into the Black Hole. The characteristic energy of the particles in the box can be related to a temperature, and he associates this temperature with the temperature of the black hole.

The implication of this thought experiment is that a black hole in a vacuum, and not in a reflecting box, would also have a temperature. The temperature is low for large black holes, and high for small black holes. If the black hole is isolated in a vacuum, the production of particles will eventually cause it to evaporate. This evaporation is really an explosion, because as it gets smaller, the production of particles goes up exponentially. A very small black hole has a very high temperature that causes it to explode and disappear in a blast of high-energy particles.

So the answer to the question is that each black hole has a unique temperature that depends only on its mass. Since the mass of black holes can range, in theory, from very small to essentially infinite, the temperature can range from very high to essentially zero.

Answer 5

Black holes dont have a "surface", they are actually a lack of a surface. If the centre is nothingness then that would make it cold, but if all the matter that enters gets compacted into a singularity then it would be hot.

Answer 6

Although a black doesn't have a solid surface, it can emit radiation (really!). The temperature of this radiation (Hawking radiation, after its discoverer) depends on the size of the hole. The temperature of the radiation from a subatomic black hole would be quite high, but the emitted temperature from, say, a stellar mass black hole, is less than the background temperature of space (about 3K) and so it absorbs energy.
Then AGAIN....the local environment of a black hole could be hot to the point of emitting hard x-rays, due to it accreting matter.

Answer 7

It is difficult to add anything to the excellent answer already given by "cosmo".

If a black hole is large enough you could pass into it, crossing its event horizon, hardly noticing it. Presumably the temperatures on either side would not be significantly different. For large black holes, then, the surface would be cold. For small ones it would be hot. But this is what cosmo has already said. His/her answer would get my vote as the best answer.

Answer 8

The surface of a black hole is, by defintion of a black hole, 0 kelvin, the coldest temperature established thus far in the known universe. In a black hole all atomic strcuture breaks down, as happens at zero kelvin.

Answer 9

i feel its vaccum out there and its usually cold...and i am talking about the surroundings and coming to the surface of the black hole... a hole is a hole is a hole.... so no surface out there......a singularity dot as u said and that need to be considered

Answer 10

It doesn't have a surface as such, but it depends on the environment - If it's in empty space then it will be cold, whereas if it's in the heart of a packed galaxy then it can be extremely hot because it sucks matter into itself at relativistic velocities, and the interaction of this matter causes intense heating.