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:
“If the hero is not a person, the emblem
Of him, even if Xenophon, seems
To stand taller than a person stands, has
A wider brow, large and less human
Eyes and bruted ears: the man-like body
Of a primitive.”
—Wallace Stevens (18791955)
“Celebrity is a mask that eats into the face. As soon as one is aware of being somebody, to be watched and listened to with extra interest, input ceases, and the performer goes blind and deaf in his overanimation. One can either see or be seen.”
—John Updike (b. 1932)
“The truth is that a Pigmy and a Patagonian, a Mouse and a Mammoth, derive their dimensions from the same nutritive juices.... [A]ll the manna of heaven would never raise the Mouse to the bulk of the Mammoth.”
—Thomas Jefferson (17431826)