Was the universe once of zero
size?
Probably not. But it was infinitely dense. It is wrong to think about outside
What happened before this?
Hard to be sure - maybe inflation (later). Something is needed to start the expansion
What is the future of the
expansion?
That depends on what the universe contains. Best current
idea is that it will expand indefinitely
Why are there galaxies?
We need to see some more
evidence....