DESI

What is dark matter and dark energy? Discover the invisible forces shaping 95% of the universe — from galaxy rotation curves to the accelerating cosmos.

The universe has been expanding for 13.8 billion years, and dark energy is currently accelerating that expansion. If it suddenly reversed and the universe began contracting, we would be heading toward a 'Big Crunch' — but the change would be too slow for any individual to notice.

In 1998, two teams studying distant Type Ia supernovae found that cosmic expansion is speeding up. The cause, dark energy, makes up about 68% of the universe's energy budget, and nobody knows what it is.