Dark energy

The largest-ever 3D map of the cosmos hints that the dark energy that’s fueling the universe’s expansion may be weakening. One community of theoretical physicists expected as much.

A generation of physicists has referred to the dark energy that permeates the universe as “the cosmological constant.” Now the largest map of the cosmos to date hints that this mysterious energy has been changing over billions of years.

By mapping the largest structures in the universe in X-rays, cosmologists have found striking agreement with their standard theoretical model of how the universe evolves.

An idea derived from string theory suggests that dark matter is hiding in a (relatively) large extra dimension. The theory makes testable predictions that physicists are investigating now.

As measurements of distant stars and galaxies become more precise, cosmologists are struggling to make sense of sparring values.

By measuring the universe’s emptiest spaces, scientists can study how matter clumps together and how fast it flies apart.

Big Freeze, Big Rip, Big Crunch, Bounce or vacuum decay? Steven Strogatz speaks with theoretical cosmologist Katie Mack about the five ways that scientists think the universe could come to an end.

Reports that the James Webb Space Telescope killed the reigning cosmological model turn out to have been exaggerated. But astronomers still have much to learn from distant galaxies glimpsed by Webb.

Two physicists have calculated that the universe has a higher entropy — and is therefore more likely — than alternative possible universes.