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Date Posted: 13:10:20 08/01/04 Sun
Author: One-eeyd Jack
Subject: About black hole evaporation and Hawking radiation....
In reply to: One-eyed Jack 's message, "Well, there are some problems with your speculation." on 01:01:23 07/31/04 Sat

The time a black hole takes to evaporate is proportional to the cube of its mass. The power of Hawking radiation is inversely proportional to the mass of the black hole, given by P = K/M2, where K is a complex constant equal to 3.563 x 1032 W kg2.

The size of a black hole's event horizon is proportional to its mass, and is given by Rs = 2GM/c2.

A black hole weighing 200 pounds on the surface of the Earth would have about 90 kilograms of mass, and would be about 2.67 X 10-20 centimeters in diameter. (This is very approximately 1,000,000,000,000 times smaller than the atoms in your brain, incidentally.) A black hole of this size would almost instantly disappear in an incredible burst of energy, expressed as Hawking radiation.

If a black hole weighing 200 pounds appeared in your brain, you would probably not get a chance to feel a 200-pound weight dragging your head toward the ground because your head would be vaporized by the black hole's explosively rapid evaporation into pure energy:

"...The Hawking radiation itself would consist of fiercely energetic particles, antiparticles, and gamma rays. Such radiation is invisible to the human eye, so optically the evaporating black hole might look like a dud. However, it is also possible that the Hawking radiation, rather than emerging directly, might power a hadronic fireball that would degrade the radiation into particles and gamma rays of less extreme energy, possibly making the evaporating black hole visible to the eye. Whatever the case, you would not want to go near an evaporating mini black hole, which would be a source of lethal gamma rays and energetic particles, even if it didn't look like much visually."

"...In the final second of its existence, the mini black hole radiates about 1000 tonnes of rest mass energy. Such an explosion is large by human standards, but modest by astronomical standards. An evaporating black hole would be detectable from Earth only if it went off within the solar system, or at best no further away than the nearest star."

)reference for the quote above)

Very interesting stuff, black holes and Hawking radiation. All of the material in this post is available from science sites on the Internet, incidentally.

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