Eli5: How come the universe is always expanding?

Question

Eli5: How come the universe is always expanding?

In: 1

Answer 1

The simple answer is dark energy, the weird answer is that we don’t know what dark energy is, its just the explanation for the energy needed for expansion.

eg.
“The universe is expanding because dark energy”

“what’s dark energy?”

“I have no idea”

“so how do you know theres dark energy?”

“because the universe is expanding”