[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: 1/f spectra

Yesterday, Steven Weinberg (who received the Nobel prize in physics for
unifying the electromagnetic weak nuclear forces) happened to mention in
his address to the Acoustical Society of America that 1/f spectra have the
unique distinction of being "scale invariant" in the sense that the energy
in an interval df is proportional to df/f.  He noted that any other law
would require some choice of units.  As a result, the 1/f nature of the
angular spectrum of the cosmic background radiation (recently verified by
observation) was predicted by cosmic inflation theory.  All this was in the
context of a talk about the relevance of acoustics to the first 380,000
years of the expanding universe, before the point at which the universe
became transparent to photons. -- jos