Wrong and wrong..
Einstein thought the universe was static..neither expanding or contracting.

He was wrong.. when the big bang theory was proven..it was also proven that the universe is constantly expanding.. not static.. and not contracting..

If you left earth.. and just travelled in one direction..you'll never return.

what about the 3rd dimension in space of up and down?
Remember there is no gravity or sense of time in space.

Cheers,
Bob.