What is the entropy of a black hole?

Answer 1

Hi Albert F

That a black hole has a quantifiable entropy is a result obtained originally by Beckenstein and by Hawking. The entropy (S) of a black hole is related to the surface area (A) of its horizon:

S = Akc^3 / 4Gh-bar

(k blotzmann's constant, c speed of light, G gravitational constant, h-bar reduced Planck's constant)

Black holes also have a characteristic (no-zero) thermodynamic temperature(T):

T = h-bar.c^3 / kGM8Pi

(M mass of hole)

The entropy of the hole gives rise to black hole thermodynamics, and equivalent thermodynamic laws for black holes:

1st law: a differential equation relating the mass, area, charge and spin
2nd law: the horizon area can't reduce (because that means the entropy would reduce)*
3rd law: you can't reach zero surface gravity (K)

* this is a classical result and so doesn't include the Hawking radiation process. If you include the Hawking process then the horizon can be reduced, and the entropy loss is compensated for by radiation emissions


There is an informational consequence (or two) to the linking of the horizon area to the black hole entropy: it is basis for a holographic interpretation of black holes (the horizon area reduces the dimensionality of the hole's information content by 1, like a hologram). There is also the difficult "information loss problem" which is probably a topic for a different question.


Hope this helps!
The Chicken

Answer 2

I'm not sure what you mean by what. But black holes have the maximum possible entropy.

Answer 3

A black hole is represented by a singularity in which matter is forced into a dot the size of a period (infinite density) and the laws of physics as we know them likely no longer apply. Entropy as defined by our laws of physics should cease to exist.

Answer 4

The classic view is, in case your math is particular adequate, then you definitely can map what has befell, and what is going to take position. (attempt that with the Lottery sometime....) For black holes... the extra huge the black hollow, the cooler that's - and, the longer that is going to exist. So, the micro-miniature black holes that the LHC become feared will be produced - they might exist for some billionths of a second, then evaporate. that they had be *very* warm, and on account that the mass interior of them doesn't be adequate to entice different mass (it turned right into a minimal of become hoping...), they might in simple terms exist, then quit to exist. for familiar black holes - image voltaic mass ones - in the adventure that they were to do not have any extra count to eat, then, *finally* that they had evaporate. And, you're accurate - interior the nice and comfy temperature lack of existence of the universe, even as all the different stars have died & their warmth has radiated away, then the purely warmth "source" may be the black holes that would (by using then) be trillions of years old. one element i'm not responsive to... they could be radiating Hawking radiation - yet i do not understand if that would move to thermal potential.... exciting question....

Answer 5

Since we can't see inside of a black hole, we don't know what's there. If it's 10,000 angels dancing on a pin, I'd say its entropy is pretty low.

Answer 6

I have no idea wha entropy means but did you knw that after billions of years black holes turn into white holes and spit out everything they swallowed up?

Can I have 10 points for telling you that pwease?

Answer 7

"...black holes are maximum-entropy objects, meaning that the maximum entropy of a region of space is the entropy of the largest black hole that can fit into it..."

Answer 8

Uh, well isn't this kind of obvious?

Entrophy is what makes time directional.

As you approach the speed of light, mass increases and time decreases. At the speed of light, as you enter the black hole, time decreases to approach zero. As it approaches zero, entrophy approachs infinity.

Answer 9

Judgment Day.

Good luck!

Rebecca
http://www.ipowergrfx.com

Answer 10

there is no matter available for thermodynamic measure