Krauss argues that what we normally think of as "nothing" isn't really "nothing." That is, even a "vacuum" contains energy.
Thanks for that info. In that case, my apologies for misinformation re Prof Krauss. I had heard him state that it was literally nothing, but if he went on to talk about vacuum energy then that's another matter (dear me, not another pun!
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Still, I think he's unwise to sow confusion by using the word 'nothing' in the first place. I, for one, don't consider the existence of several dimensions containing vacuum energy to be what we "normally think of as nothing". The distinction draws a line between physics and metaphysics.
It looks like there's a mind-boggling amount of energy lurking in a vacuum...
"However, in both Quantum Electrodynamics (QED) and Stochastic Electrodynamics (SED), consistency with the principle of Lorentz covariance and with the magnitude of the Planck Constant requires it [vacuum energy] to have a much larger value of 10^113 Joules per cubic meter"
http://en.wikipedia.org/wiki/Vacuum_energyI don't really know how much energy that is, but I do know that's more than enough to boil an egg (no, really, it is)...and the funny thing is, as space expands, the vacuum energy per unit of volume remains the same.
