Dark matter

The irreversibility of time may be a clue as to what makes up the universe’s dark matter.

The physicist James Bullock explains how a complicated “dark sector” of interacting particles may illuminate some puzzling observations of the centers of galaxies.

For five years physicists have been tantalized by possible evidence of dark matter in the Milky Way’s center. But new results from small satellite galaxies have complicated the story.

Katherine Freese, a physicist who will soon lead the Nordic Institute for Theoretical Physics, reflects on the hunt for dark matter and how dark matter heating may have produced the first stars.

A new analysis strengthens the case that gamma rays emanating from the center of the Milky Way come from dark matter particles known as WIMPs.

Whispers of the elusive particles are becoming stronger with a series of signals that appear to be zeroing in on a leading contender.

Three “extremely large telescopes” poised to begin observations within a decade could help answer some of the universe’s oldest and best-kept secrets.