  When a classical black hole is perturbed, its relaxation is governed by a set
of quasinormal modes with complex frequencies \omega= \omega_R+i\omega_I. We
show that this behavior is the same as that of a collection of damped harmonic
oscillators whose real frequencies are (\omega_R^2+\omega_I^2)^{1/2}, rather
than simply \omega_R. Since, for highly excited modes, \omega_I >> \omega_R,
this observation changes drastically the physical understanding of the black
hole spectrum, and forces a reexamination of various results in the literature.
In particular, adapting a derivation by Hod, we find that the area of the
horizon of a Schwarzschild black hole is quantized in units \Delta
A=8\pi\lpl^2, where \lpl is the Planck length (in contrast with the original
result \Delta A=4\log(3) \lpl^2). The resulting area quantization does not
suffer from a number of difficulties of the original proposal; in particular,
it is an intrinsic property of the black hole, independent of the spin of the
perturbation.
