How wrinkled is the surface of a black hole?

Rafael D. Sorkin

( Instituto de Ciencias Nucleares, UNAM, A. Postal 70-543, D.F. 04510, Mexico
and
Department of Physics, Syracuse University, Syracuse, NY 13244-1130, U.S.A. )

Abstract

We present evidence that, below a certain threshold scale, the horizon of a black hole is strongly wrinkled, with its shape manifesting a self-similar (``fractal'') spectrum of fluctuations on all scales below the threshold. This threshold scale is small compared to the radius of the black hole, but still much larger than the Planck scale. If present, such fluctuations might account for a large part of the horizon entropy.