Now
waves have a
certain wavelength, and common experience
of such
waves as may be seen, for example, on the surface
of the sea tells us that an object which is very much smaller than the length
of the
wave has no appreciable effect upon it.
These
waves come in all possible
wavelengths, and their presence implies that empty space contains a
certain amount
of energy — an energy that we can't tap, but that is always there.