Paper referred to http://www.calphysics.org/zpe.html In one paragraph they talk about (wave fragments), How could such an enormous energy not be wildly evident? There is one major difference between zero-point electromagnetic radiation and ordinary electromagnetic radiation. Turning again to the Heisenberg uncertainty principle one finds that the lifetime of a given zero-point photon, viewed as a wave, corresponds to an average distance traveled of only a fraction of its wavelength. Such a wave ''fragment'' is somewhat different than an ordinary plane wave and it is difficult to know how to interpret this. And later on they say Recent work by Christian Beck at the University of London and Michael Mackey at McGill University may have resolved the 120 order of magnitude problem. In that case dark energy is nothing other than zero-point energy. In Measureability of vacuum fluctuations and dark energy and Electromagnetic dark energy they propose that a phase transition occurs so that zero-point photons below a frequency of about 1.7 THz are gravitationally active whereas above that they are not. If this is the case, then the dark energy problem is solved: dark energy is the low frequency gravitationally active component of zero-point energy. How can a wave fragment have a frequency?