
NASA’s Neil Gehrels Swift Observatory has ended its science mission now that the spacecraft is orbiting less than 171 miles (275 kilometers) above Earth’s surface. The greater atmospheric drag at this height prevents the satellite’s telescopes from steadily gazing at their astronomical targets. Swift conducted its final observation on Oct. 20. It is expected to […]

A new study of two supernova remnants, the debris left behind after stars explode, suggests the explosions came from stellar siblings that once orbited each other. The first star’s detonation sent its binary companion hurtling through space, and then, after traveling for thousands of years, the surviving star blew up too.