A theory/hypothesis

[Paddy™]

Lawrence Krauss has a fairly recent book about that very question, Ash. I don't understand any of it, of course haha. But the gist of it is, there's no such thing as "nothingness" in the universe, in that even empty space is a bubbling soup of quantum particles, constantly popping in and out of existence (apparently to/from nowhere). Empty spaces weighs something, in other words.

I'm sure that clears everything up for you XD

EDIT: Here's Lawrence giving a talk on the subject:

https://www.youtube.com/watch?v=-EilZ4VY5Vs