se virtual pairs cause the atoms electron to shake in its orbit. Now, if a virtual pair appears near a black hole, one particle might become caught up in a the holes gravity and dragged in, leaving the other without its partner. Unable to annihilate and turn back into energy, the lone particle must become real, and can now escape the black hole. Therefore, mass and energy are lost; they must come from someplace, and the only source is the black hole itself. So the hole loses mass. If the hole has a small mass, it will have a small radius. This makes it easier for the virtual particles to split up and one to escape from the gravitational pull, since they can only separate by about a wavelength. Therefore, hotter black holes (which are less massive) evaporate much more quickly than larger ones. The evaporation timescale can be derived by using the expression for temperature, which is inversely proportional to mass, the expression for area, which is proportional to mass squared, and the blackbody power law. The result is that the time required for the black hole to totally evaporate is proportional to the original mass cubed. As expected, smaller black holes evaporate more quickly than more massive ones. The lifetime for a black hole with twice the mass of the sun should be about 10^67 years, but if it were possible for black holes to exist with masses on the order of a mountain, these would be furiously evaporating today. Although only stars around the mass of two suns or greater can form black holes in the present universe, it is conceivable that in the extremely hot and dense very early universe, small lumps of overdense matter collapsed to form tiny primordial black holes. These would have shrunk to an even smaller size today and would be radiating intensely. Evaporating black holes will finally be reduced to a mass where they explode, converting the rest of ...
