David Spence asked:
If a Black Hole's gravitational pull is so strong that light itself (and I presume all aspects of the Electro Magnetic Radiation) cannot escape from it, what (if any) temperature would a Black Hole be at its surface if or within? (assuming it is either equal to or just above Absolute Zero of - 273.15 Celsius, - 459.67 Fahrenheit)
Lerwick, Shetland Islands, Scotland
Dominic - Itís actually incredibly hot. At least the surface of the black hole is very hot because as material is falling in towards the black hole, itís being compressed into an ever smaller volume of space. There's less space close to the black hole than there is far away from it and so, that material is elevated to tremendous pressures and tremendous temperatures of hundreds of millions of degrees, which means it doesnít glow red hot. It glows hot in ultraviolet and x-ray light. And that is how we can detect that black holes are there because we can set this very hot material producing x-rays with x-ray telescopes. Once itís actually past the event horizon, itís very difficult for us to say what happens to that material beyond that point because we can't see it and we donít fully understand what laws of physics apply inside the black hole itself.
In theory, the temperature as seen from outside a black hole is thought to be determined by Hawking Radiation.
We cannot know by observation but simple theoretical physics can tell us sometthing
Some black hole candidates reveal themselves because the accretion disk around them is so hot that it emits X-Rays as matter is shredded and falls into the black hole.
Heh, temperatures are interesting, as they are symmetry breakers. Wish we had some way to find out, there are some ideas with using light to simulate a Black Hole?
I am intrigued with there being any temperature on the surface, if indeed there is one, of a blackhole, if the laws of thermodynamics is anything to go by. I understand that temperature is a measurement of the energy state of atoms in motion as well as the density (pressure) in which x number of atoms occupy in a given space. However, if one is to believe that matter cannot travel faster than the speed of light, and that light (and one would assume matter (atoms) itself cannot escape the gravitational pull of a blackhole, how could one actually measure any temperature of a blackhole unless one is measuring the energy of the matter going into a blackhole, but not the actual blackhole itself.........since matter and energy cannot escape, as mentioned previously, the gravitational pull (surface I suppose) pull???? :D unstman, Sun, 12th Aug 2012
@unstman - there are two extreme conditions under which you could observe a black hole:
might be that just like there are different types of planets, stars, asteroids, comets, solar systems, galaxies, etc.