How can the universe be speeding up in its expansion? Since gravity is the only force that controls wouldn’t the universe ultimately always contract again over time because gravity would eventually win out over the initial acceleration caused by the big bang?

Question

How can the universe be speeding up in its expansion? Since gravity is the only force that controls wouldn’t the universe ultimately always contract again over time because gravity would eventually win out over the initial acceleration caused by the big bang?

In: Physics

Answer 1

There is a thing called the cosmological constant, or energy density of space, or dark energy, which forces the universe to get progressively bigger. As is obvious from its name, we don’t really know what it is. This is an area of active research.