how does a blackhole evaporate?

Question

I read that due to vacuum fluctuations one can get a particle and its antiparticle out of nowhere. one particle gets into the black hole while the other doesn't in a fluctuation near a black hole.
As a result we observe as though the black hole has emitted a particle. All this theory was good but the actual happening is that the black hole gained a particle isn't? and a black hole gains extra mass by sucking up the hydrogen near it (the accretion disk).
So how exactly do we say a black hole evaporates?

Answer 1

When the anti-particle runs into a particle inside the black hole they annihilate each other. This reduces the mass inside.

A black hole will gain matter from an accretion disk only it is part of a binary (or more) system. In other words, there's a star reallly close to supply new matter to the black hole. In this case I don't know if the black hole would be gaining or losing mass. I'd guess gain. But eventually the neighboring star will stop losing matter to the black hole and the black hole will then evaporate.

Answer 2

Hawking Radiation.

Hawking Radiation is the antiparticle effect that demiurge42 is talking about.

According to Wikipedia: http://en.wikipedia.org/wiki/Hawking_Radiation
"Physical insight on the process may be gained by imagining that particle-antiparticle radiation is emitted from just beyond the event horizon. This radiation does not come directly from the black hole itself, but rather is a result of virtual particles being "boosted" by the black hole's gravitation into becoming real particles.

A more precise, but still much simplified view of the process is that vacuum fluctuations cause a particle-antiparticle pair to appear close to the event horizon of a black hole. One of the pair falls into the black hole whilst the other escapes. In order to preserve total energy, the particle which fell into the black hole must have had a negative energy (with respect to an observer far away from the black hole). By this process the black hole loses mass, and to an outside observer it would appear that the black hole has just emitted a particle.

An important difference between the black hole radiation as computed by Hawking and a thermal radiation emitted from a black body is that the latter is statistical in nature, and only its average satisfies what is known as Planck's law of black body radiation, while the former satisfies this law exactly. Thus thermal radiation contains information about the body that emitted it, while Hawking radiation seems to contain no such information, and depends only on the mass, angular momentum and charge of the black hole. This leads to the Black hole information paradox."

Steven Hawking's theory is that the virtual particle is formed of two particles that form and instantly destroy each other. These virtual particles are created because of vacuum fluctuations at the quantum level. However, if a virtual particle is created too close to the black hole then before the virtual particles can destroy each other one is absorbed into the black hole. To balance the equation of energy the particle inside the black hole is destroyed so the black hole seems to be emitting half of a pair of virtual particles. Hawking Radiation has been detected, but the theory is still being argued about.

Further more the virtual particles don’t account for the conservation of information test theory in physics. Hawking has agreed that the conservation of information is true about black holes and that any information lost inside a black hole remains there and is not lost from the universe; the Hawking Paradox.

What all this means is that due to a strange action of the universe the matter inside of a black hole is being robbed by virtual particles. If the black hole goes into an empty area of space then it stops sucking in matter and so it starts to evaporate. The problem with understanding this is that the virtual particle is an undefined particle that exists for only a few seconds, they cannot be measured very well and they actually only appear when you are not looking for them. I know it sounds strange and I don’t claim to understand all of it, but the physics community accepts the theory and uses some pretty high power math and strange quantum physics formulas to allow for them. For more information read this article: http://en.wikipedia.org/wiki/Vacuum_fluctuations. Which will make it all as clear as mud; I am only a lay man, not a physicist so some things I have to take on faith believing that the people, like Hawking, who understand this math and these theories, are right. I have that faith because their math and experiments are reproducible and have survived review by other physicists.

Answer 3

EXCELLENT QUESTION!


The particles you are referring to are called virtual particals, in a sense they are not real particles. Normally, quantum fluctuations in a vacuum cause these virtual particals to pop into existance for a brief moment in time, and then annialate one other nearly instantaneously.

Now because of the law of conservation of mass. Mass cannot be created nor destroyed, only changed from one energy and back. So the universe shall have the same amount of fermions (protons, neutrons, quarks) at all times.

So the only way a particle may pop into existence is for an antiparticle to be created along side it. Let's say the antiparticle falls into the black hole, it's mass has just been decreased, at the expense of a real particle escaping.

Hawking radiation is what it's called. Stephen says that the surface area of a black hole's event horizon is dependent on the total "entropy" of the black hole.

Answer 4

If a black hole could exist it would not be able to evaporate.
Something called Hawking radiation is said to diminish the mass of a black hole.
Virtual particles are said to emerge from space then merge and annihilate each other.
If a pair emerges close to the event horizon one of the two could be trapped by the black hole and one escape to space apparently diminishing the mass by half the virtual particle.
There are some very good reasons why this scenario is a stretch and more good reasons why a black hole is a non-viable entity.

Answer 5

There "may" be a point at which the strength of a black hole weakens if it has sucked in too much matter and energy. For all intensive purposes though the apex of a black hole is infinite. Until we can observe and document faster then light phenom we will never know.

FYI, black holes do not just suck up hydrogen, they suck up everything! Once anything gets to a certain point near the accretion disk, it is doomed, nothing can escape it, It is an infinite gravity well, unless something has infinite power +1, nothing cannot escape it.

It is possible that dark matter and energy are able to escape a black hole since they do not adhere to "normal" laws of physics that we know.

Answer 6

The problem is that the English language does not have the correct words to describe what is happening. Matter has properties that are similar to what we call a particle but matter also has properties that are more consistent with a wave. The English description of situations using the analogy of a particle nature of matter are not complete. Without significantly advanced Math one can not adequately describe what is happening.

Answer 7

Hi. Through Hawking Radiation. http://www.answers.com/main/ntquery?s=Hawking+Radiation&gwp=13

Answer 8

the blackhole evaporates by hawking radiation

Answer 9

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Answer 10

It doesn't. It remains dormant in huge time cycles.