"Since 1974, the guiding principle for building extensions of the standard model has been the so-called desert hypothesis. ... Its premise is that there is no new physics between the energy scales of electroweak unification (109 GeV or 1 TeV) and the vicinity of the Planck mass MPl (1019 GeV). That implies an enormous "desert," 16 orders of magnitude wide, where one would expect to encounter nothing new. MPl is the mass at which a particle's Compton wavelength becomes equal to its Schwarzschild radius—a realm where one can't do without a quantum theory of gravity. ... The leading contender for the elaboration of the desert picture has been the supersymmetric extension of the standard model ..."