Where does the extra space come from as the universe expands? and if it’s just stretching, does that mean it somehow is getting thinned out?

Question

Where does the extra space come from as the universe expands? and if it’s just stretching, does that mean it somehow is getting thinned out?

In: 47

Answer 1

It is completely unknown.

One theory that I like says that the reason for the universe’s expansion is that dark energy is a fundamental property of spacetime. It’s the nature of space to grow, and as it does, there exists more space which also has its own dark energy.

In this way, space expands faster and faster as more space comes into existence. It increases in volume forever while all the matter and energy inside is gradually pulled apart.