An alarm indicated a possible leak of toxic ammonia. Astronauts evacuated the U.S. side of the station. Later, NASA said the problem might have been a faulty sensor.
Kilauea ranks hottest in terms of total energy. It's been erupting for decades. Meanwhile, Iceland’s Holuhraun eruption radiated the most heat for a single event.
It was an M-class flare, and it might have produced a brief communications blackout on Monday night. But no CME - coronal mass ejection - is headed our way.
The SpaceX Dragon cargo spacecraft successfully docked with the International Space Station on January 12, bringing needed supplies to the six astronauts aboard.
By associating with early humans, dogs enjoyed new foods and the relative safety of human camps. Eventually, dogs traveled the world with their two-legged masters.
Scientists measure the space-time warp in the gravity of a binary star and find the mass of a fast-spinning pulsar -- just before the pulsar disappears.
A flare from our galaxy's core 400 times brighter than usual, in September, 2013. Over a year later, a second large flare. Now scientists are trying to explain why.