Astrophysics

Astronomers are mystified by a strange star explosion in a distant galaxy that might be a relic from an earlier cosmological era.

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.

The core of a neutron star is such an extreme environment that physicists can’t agree on what happens inside. But a new space-based experiment — and a few more colliding neutron stars — should reveal whether neutrons themselves break down.

Newly discovered “standard sirens” provide an independent, clean way to measure how fast the universe is expanding.

Astronomers have for the first time matched a gravitational-wave signal to a kilonova’s burst of light, observations that will “go down in the history of astronomy.”

Repeating radio bursts are among the most mysterious phenomena in the universe. A new theory explores how some of their puzzling properties can be explained by galactic lenses made of plasma.

Even as the solar eclipse was mesmerizing millions, astronomers were training their space- and land-based telescopes on a far more violent astrophysical event.

The first major results from the Dark Energy Survey signal the start of a new era of cosmology.

Astronomers thought that all Type Ia supernovas shine with the same brightness, making them incredibly useful cosmic yardsticks. But uncertainty over what causes these explosions has led researchers to reconsider their assumptions.