dark matter

photo of spiral galaxy
NASA

Scientists talk a lot about dark matter. It sounds exciting, but what does it do for us?

"If the dark matter wasn't there, the galaxy should fly apart," Case Western Reserve University physics professor Glenn Starkman said.

Starkman chases dark matter for a living. Scientists started thinking about dark matter in the middle of the last century, when they looked at galaxies and saw something wasn't quite right.