[TigerTale]

The vacuum has energy, and "contains" space--so technically it's not "nothing." Right? Or am I confused?

Can't we say that even the pre-Big Bang singularity had--at a minimum--mass, and so was not "nothing?"

If you can explain the phenomenon of vacuum energy in layman's terms, I would appreciate it.

Sorry, this previous post was intended for SubMareener.

[SubMareener]

It appears from the experimental evidence, that what we call "empty space" is actually made up of a froth of "stuff". It is a little like the air we breath. You can't see it, but is has effects you can measure.

In the current wave/particle quantum models, this is described as particles and their anti particles suddenly materializing in free space. The now real, virtual particles, recombine before anyone notices that they are there, usually.

There are exceptions that make it so one can notice. Near the event horizon of a black hole, one particle could fall in, while the other escapes. This is the effect that causes black holes to gradually evaporate.

The other effect, an I have forgotten its name, takes place when the vacuum is very thin between two metal plates. In this case, the virtual particles made real get trapped in the metal and can't recombine with their partners. This causes a measurable force between the plates.