Astrophysics

Called Olbers’ paradox, the seemingly simple mystery of the sky’s darkness is something that stumped astronomers for centuries

The nearby star Vega, featured in the 1997 movie Contact, appears to have a smooth disk devoid of giant planets for reasons we can’t explain

The Chandra X-ray Observatory is facing closure. Shutting it down would be a loss to science as a whole

Finding a perfect sphere is actually pretty difficult

A strange supernova remnant first appeared as a “guest star” seen in 1181 by sky watchers in China and Japan

Experiment shows that a nuclear explosion could save the planet from a deadly asteroid impact

Wispy whorls on the moon’s surface are as lovely as they are strange. Scientists are starting to unravel their origins

A famous prediction that microchips improve exponentially over time can be applicable in unrelated developments, such as the technology used to discover colliding black holes

Andromeda and the Milky Way may collide, or they may safely swing past each other. Time will tell

A new explanation for the Wow! signal suggests it was a chance detection of a furious flare crashing into a hydrogen cloud. But some researchers doubt that this idea has truly cracked the case

Dark matter has turned out to be more elusive than physicists had hoped

Surging solar activity means enormous sunspots are in the space-weather forecast. Here’s how to view them safely