CMB

The recent discovery of some of the first galaxies in the universe illuminates the darkest era in cosmic history.

Most every cosmologist believes the universe is flat. A new analysis argues that it’s closed.

Astronomers have known where the universe’s missing matter has been hiding for the past 20 years. So why did it take so long to find it?

For decades, astronomers weren’t able to find all of the atomic matter in the universe. A series of recent papers has revealed where it’s been hiding.