Anonymous

Your question is not well written. I assume you are asking if those two atoms 20 billion light years away "from each other" would eventually meet, but your question seems to ask if the universe would meet itself.

Anonymous

It would depend on their direction of motion. If they are moving directly at each other, they will meet. Any other morion. they will not meet.

Anonymous

only if they are moving extremely close to an intersecting course at the start. The odds of that are pretty low.

Anonymous

I think so, given enough time