International scientists say they've discovered an 18-kilo (40-pound) meteorite in eastern Antarctica, the largest found in that area in 25 years.

The Brussels-based International Polar Foundation said Thursday the meteorite is an "ordinary chondrite," the most common meteorite. It was discovered Jan. 28, and is undergoing a special thawing process in Japan so water won't penetrate it before it's studied.

Levels of carbon dioxide rose hand-in-hand with warming at the end of the last Ice Age, according to a study Thursday that deals a blow to climate skeptics.

French researchers said they had answered a riddle that has perplexed scientists.

There's a new spin on supermassive black holes: They're incredibly fast, astronomers say.

It's long been suspected that gigantic black holes lurking in the heart of galaxies rotate faster and grow larger as they feast on gas, dust, stars and matter. But there hasn't been a reliable measurement of the spin rate of a black hole until now.

Researchers steering a remote-controlled submarine around the world's deepest known hydrothermal vents have collected numerous samples from sunless depths of the Caribbean Sea where blazing hot, mineral-rich fluid gushes from volcanic chimneys that look like gnarled tree stumps.

Jon Copley, chief scientist for the expedition of Britain's National Oceanography Center, said Wednesday he believes that laboratory analysis in the coming months will reveal some new life forms that have evolved in the pitch-black vent areas of the Cayman Trough, more than 3 miles (5 kilometers) below the sea's surface between the Cayman Islands and Jamaica.

The largest genetic study of mental illnesses to date finds five major disorders may not look much alike but they share some gene-based risks. The surprising discovery comes in the quest to unravel what causes psychiatric disorders and how to better diagnose and treat them.

The disorders — autism, attention deficit-hyperactivity disorder or ADHD, bipolar disorder, major depressive disorder and schizophrenia — are considered distinct problems. But findings published online Wednesday suggest they're related in some way.

Beijing residents were urged to stay indoors Thursday as pollution levels soared before a sandstorm brought further misery to China's capital.

A thick blanket of smog covered large swathes of the country in the morning, causing residents to once again dig out face-masks as China's grueling winter of pollution continues.

An international consortium of scientists said on Wednesday they had collected 1.5 million specimens of wildlife in an unprecedented mission to document the biological treasures of Papua New Guinea.

Marine invertebrates, fungus, algae, plants and roughly half a million insects were among the bounty from the three-month exploration of one the world's last biodiversity hotspots, they said at a press conference in Paris.

A campaign by global environmental movement Earth Hour to get promises of action from individuals and organisations has spread to at least 50 countries, its chief executive said Wednesday.

Andy Ridley said the "I Will If You Will" campaign, launched in 2012 in 13 countries, is expected to expand its geographic reach almost fourfold this year, strengthening the group's impact beyond an annual lights-out event.

Hyperbaric chambers have been used for decades to treat divers with the bends, burn victims and people with traumatic injuries, but in the U.S. they're increasingly being used on ailing pets.

Doctors at the University of Florida's College of Veterinary Medicine have recently used an oxygen chamber on dogs, cats, ferrets, rabbits and one monkey.

The vast majority of the Earth's estimated 13 million species are still unknown and to describe them all would take up to 2,000 years, according to a leading Brazilian scientist.

"We estimate that there are a total of around 13 million species (known and unknown) in the world," Thomas Lewinsohn, a renowned professor of ecology at the State University of Campinas (UNICAMP) in Sao Paulo state.