The NASA rover Curiosity has beamed back pictures of bedrock that suggest a fast-moving stream, possibly waist-deep, once flowed on Mars — a find that the mission's chief scientist called exciting.

There have been previous signs that water existed on the red planet long ago, but the images released Thursday showing pebbles rounded off, likely by water, offered the most convincing evidence so far of an ancient streambed.

The Australian government admits the Great Barrier Reef has been neglected for decades after a study showed it has lost more than half its coral cover in the past 27 years.

Environment Minister Tony Burke said research released Tuesday by scientists from the Australian Institute of Marine Science and the University of Wollongong should be setting off alarm bells across the country.

A giant supply ship burned up over the South Pacific early Wednesday in a self-destruct operation after a six-month mission to the International Space Station, the European Space Agency (ESA) said.

Laden with rubbish from the ISS, the Automated Transfer Vehicle (ATV) undocked from the orbital outpost last Friday to begin its final maneuvers.

From missing seismic devices to insufficient emergency back-up systems, stress tests on Europe's nuclear power plants show hundreds of problems requiring billions in new investment, an EU report showed Tuesday.

In the report obtained by Agence France Presse, the European Commission estimates the cost of improving safety at 134 reactors "in the order of 10-25 billion euros" ($13-$32 billion) and wants the upgrades monitored and finalized by 2015. But it demands no plant closures.

Australia's Great Barrier Reef has lost more than half its coral cover in the past 27 years due to storms, predatory starfish and bleaching linked to climate change, a study found Tuesday.

The research by scientists from the Australian Institute of Marine Sciences (AIMS) and the University of Wollongong warned that coral cover on the heritage-listed reef -- the world's largest -- could halve again by 2022 if trends continued.

When a bio-medical study is retracted, most of the time it is because of misconduct rather than error, a report published Monday said.

Two-thirds of all retractions around the world stem from acts like fraud, suspected fraud or plagiarism, it added.

A team of New Zealand scientists claimed to be a step closer to producing allergy-free milk Tuesday, using a genetically-modified cow for their medical breakthrough.

The team at the AgResearch Institute said they had bred the first cow in the world to produce high-protein milk with significantly reduced amounts of a protein believed responsible for allergies.

Plans to use an array of powerful air cannons in an undersea seismic study near a Central California nuclear power plant have federal and state officials juggling concerns over marine life with public safety.

Pacific Gas & Electric Co. wants to use big air guns to emit strong sound waves into a large, near-shore area that includes parts of marine reserves to make three-dimensional maps of fault zones, some of which were discovered in 2008, near its Diablo Canyon nuclear power plant.

A Chinese rocket on Saturday successfully launched a Venezuelan earth-observation satellite into orbit, state media said.

The satellite, dubbed "Generalissimo Francisco de Miranda" after the major Venezuelan independence figure, was launched from the northwest Jiuquan base in the Gobi desert using a 'Long March' class rocket, said Xinhua.

An Alaska scientist whose observations of drowned polar bears helped galvanize the global warming movement has been reprimanded for improper release of government documents.

An Interior Department official said emails released by Charles Monnett were cited by a federal appeals court in decisions to vacate approval by the Bureau of Ocean Energy Management of an oil and gas company's Arctic exploration plan.