[Doctor Stochastic]

What would you call the place where the marble-sized universe was located?
Everywhere.

What were its physical properties?
Very dense.

Do we say that an infinitely large space containing nothing, a total vacuum, was then and has since been filled by a universe of objects ranging from galaxies to sub-atomic particles?
No. Space is what is expanding.

[ExGeeEye]

Pardon my density...

Space is what is expanding.

Into what?