NASA's Mars rover has discovered gravel once carried by the waters of an ancient stream that "ran vigorously" through the area, the U.S. space agency said Thursday.

Scientists had previously found other evidence of the one-time presence of water on the Red Planet, but this is the first time stream bed gravel has been discovered.

A Chinese icebreaker docked Thursday at Shanghai after becoming the first Chinese vessel to cross the Arctic Ocean, a landmark trip that is part of Beijing's efforts to expand its presence in the Arctic.

With melting icecaps accelerating the opening of new shipping routes and the exploration of oil, gas and mineral deposits in the Arctic, China has been eager to gain a foothold in the region.

The International Space Station may have to move to avoid some space junk.

NASA said debris from an old Russian satellite and a fragment from an Indian rocket could come too close to the station on Thursday. The station would be moved Thursday morning if necessary, NASA said Wednesday.

More than half the cases of severe intellectual disability caused by genetic defects are the result of random mutations, not inherited, a European study published Thursday suggests.

The findings of the small-scale study give hope to parents of children born with a severe intellectual disabilities who are worried about having another baby with the same condition, said Anita Rauch, a researcher at the Institute of Medical Genetics in Zurich who was one of the study's lead authors.

Biologists on Wednesday said they had unlocked secrets about the vampire squid, a mysterious creature that feeds on the decaying dead in the unlit depths.

The squid is so weird that it is known as a "phylogenetic relic." It has the honour of occupying a taxononomic category all of its own, combining features of octopuses and squids in a unique evolutionary formula that has survived for millions of years.

The countdown is on for skydiver Felix Baumgartner. In just two weeks, the Austrian parachutist will attempt to go supersonic when he jumps from a record altitude of 23 miles (37 kilometers) over the U.S.

Baumgartner expects to reach a top speed of 690 mph (1,110 kph) and break the sound barrier with only his body.

NASA's future plans to explore Mars may end up using astronauts as space messengers.

The new idea surfaced as a special team looking for a new Mars robotic exploration plan released a preliminary report Tuesday.

The U.S. weather satellite that tracks the East Coast and Atlantic hurricanes is broken.

Meteorologists are scrambling to fill in lost data for forecasters with a spare satellite and help from a European satellite.

The infection is as grim as it sounds: "Zombie bees" have a parasite that causes them to fly at night and lurch around erratically until they die.

And experts say the condition has crept into Washington state.

The brain that revolutionized physics now can be downloaded as an app for $9.99. But it won't help you win at Angry Birds.

While Albert Einstein's genius isn't included, an exclusive iPad application launched Tuesday promises to make detailed images of his brain more accessible to scientists than ever before. Teachers, students and anyone who's curious also can get a look.