Large Extra Dimensions
Formulae from the previous section are only applicable if laws of gravity are approximately valid all the way down to the Planck scale. In particular, for black holes with masses below Planck mass (~10−5 g), they result in unphysical lifetimes below Planck time (~10−43 s). This is normally seen as an indication that Planck mass is the lower limit on the mass of a black hole.
In the model with large extra dimensions, values of Planck constants can be radically different, and formulas for Hawking radiation have to be modified as well. In particular, the lifetime of a micro black hole (with radius below the scale of extra dimensions) is given by
where is the low energy scale (which could be as low as a few TeV), and n is the number of large extra dimensions. This formula is now consistent with black holes as light as a few TeV, with lifetimes on the order of "new Planck time" ~10−26 s.
Read more about this topic: Hawking Radiation
Famous quotes containing the words large, extra and/or dimensions:
“Miss C_____ is ... remarkably neat in her person and is uncommonly diligent in every part of useful economy.... She hath indeed under her father’s tuition acquired ... a large share of real learning of almost all the living and dead languages. Nor was the leisure which she found for such acquirements produced by neglecting anything necessary or useful for the family, but by the most assiduous industry.”
—Sarah Fielding (1710–1768)
“I did toy with the idea of doing a cook-book.... The recipes were to be the routine ones: how to make dry toast, instant coffee, hearts of lettuce and brownies. But as an added attraction, at no extra charge, my idea was to put a fried egg on the cover. I think a lot of people who hate literature but love fried eggs would buy it if the price was right.”
—Groucho Marx (1895–1977)
“Words are finite organs of the infinite mind. They cannot cover the dimensions of what is in truth. They break, chop, and impoverish it.”
—Ralph Waldo Emerson (1803–1882)