Cosmology

It was an old idea of Stephen Hawking’s: Unseen “primordial” black holes might be the hidden dark matter. A new series of studies has shown how the theory can work.

Cosmologists have concluded that the universe doesn’t appear to clump as much as it should. Could both of cosmology’s big puzzles share a single fix?

Detailed computer simulations have found that a cosmic contraction can generate features of the universe that we observe today.

Modified gravity theories have never been able to describe the universe’s first light. A new formulation does.

Astronomers are discovering that magnetic fields permeate much of the cosmos. If these fields date back to the Big Bang, they could solve a major cosmological mystery.

The astrophysicist and social media phenom Katie Mack is ready to tell you about the fate of the universe.

Einstein’s equations describe three canonical configurations of space-time. Now one of these three — important in the study of quantum gravity — has been shown to be inherently unstable.

Physicists have proposed extra cosmic ingredients that could explain the faster-than-expected expansion of space.

In our mind’s eye, the universe seems to go on forever. But using geometry we can explore a variety of three-dimensional shapes that offer alternatives to “ordinary” infinite space.