How do we know the universe will continuously expand and never contract?

Question

How do we know the universe will continuously expand and never contract?

In: 2

Answer 1

We don’t really “know” that, we can’t look into the future after all, but the universe is not just expanding, it’s also expanding faster and faster instead of slowing down, so it’s obvious to assume that it won’t stop.

Scientists used to assume that gravitational pull would slow the expansion down over time and ultimately grind it to a halt and reverse it at some point, but further observations showed that it wasn’t slowing down at all and was instead speeding up.