cosmology

Two ways of measuring the universe’s expansion rate yield two conflicting answers. Many point to the possibility of new physics at work, but a new analysis argues that unseen errors could be to blame.

A surprise discovery announced a month ago suggested that the early universe looked very different than previously believed. Initial theories that the discrepancy was due to dark matter have come under fire.

The amount of energy infusing empty space seems too small to explain without a multiverse. But physicists have at least one alternative left to explore.

Two methods of measuring the neutron’s longevity give different answers, creating uncertainty in cosmological models. But no one has a clue what the problem is.

Cosmologists have shown that it’s theoretically possible for a contracting universe to bounce and expand. The new work resuscitates an old idea that directly challenges the Big Bang theory of cosmic origins.

It weighs as much as 780 million suns and helped to cast off the cosmic Dark Ages. But now that astronomers have found the earliest known black hole, they wonder: How could this giant have grown so big, so fast?

Astronomers generally stay away from the “Zone of Avoidance.” When one astronomer didn’t, she found a giant cosmic structure that could help explain why our galaxy moves so fast.

New data tracking the movements of millions of Milky Way stars have effectively ruled out the presence of a “dark disk” that could have offered important clues to the mystery of dark matter.

The Zoomable Universe, a new book by the astrobiologist Caleb Scharf, the illustrator Ron Miller and 5W Infographics, tours the universe’s 62 orders of magnitude.