Cosmology

Researchers have nailed down an elusive quantity called baryon number, which may be responsible for the cosmic mismatch between matter and antimatter

First glimpsed as “little red dots” in deep-space images from the James Webb Space Telescope, these giant, gas-shrouded black holes are full of surprises

A private spacecraft launched to boost the decaying orbit of NASA’s Swift Observatory is now suffering from potentially mission-ending malfunctions

A recent study in the journal Nature carries cosmos-quaking implications for our understanding of the universe—except a new preprint says that it’s wrong

The exoplanet telescope TESS revealed a distant world using an entirely different detection method than the one it was built around

A new study claims that the universe isn’t entirely the same no matter where you look—a radical proposal

The evidence is mounting: this interstellar visitor is even older and weirder than anyone thought

Astronomers may have found the remains of two long-dead stellar siblings

The M.I.T. cosmologist shares his thoughts on physics, the federal funding of science and the resilience of the scientific community

A blip of light in the outer reaches of the Milky Way might be a bizarre black hole born at the beginning of time itself—and the long-sought solution to the mystery of dark matter. Astronomers are calling it “Phoebe”

Where did stars, and light itself, come from? Is there a hidden sector of particles and forces called “dark energy” affecting the cosmos?

Deep surveys of the sky have turned up galaxies vastly larger than our own. Are there even bigger ones yet to be seen?