One of the brightest—and most puzzling—star deaths known was caused either by a pair of giant colliding stars or a repeatedly exploding sun, scientists say.

Oregon scientists have derived stem cells from cloned monkey embryos, a potential boon for human treatments. (AP)

Spaniels and poodles sniff out explosives, drugs, bodies in rubble, and even cancer at the Detector Dogs World Congress in Barcelona, Spain.

More than 30,000 birds were killed by last weekend's Black Sea oil spill. Meanwhile California environmentalists are cleaning birds by hand after spilled oil there.

A Russian oil tanker broke apart in the northeastern Black Sea. The accident may become the worst environmental disaster to hit the region in years.

A South Korean house built to look like a toilet is no joke. Its owner aims to raise awareness about the importance of sanitation.

Ribbons of oil spread through the San Francisco Bay this week, coating birds and other wildlife.

An eight-limbed girl, a celebration of skulls, and a monster hailstorm are among the world's most eye-opening images this week.

The 66-million-year-old molar suggests that India might have played a key role in the rise and spread of hoofed mammals, a new study says.

Yellowstone National Park is rising more than three times faster than has ever been measured, thanks to growing pressure from the ancient volcano on which the park sits.

Supermassive black holes at the centers of distant galaxies are the most likely sources of high-energy cosmic rays, a new study says.

Poverty and tradition drive some Haitians to eat cakes of clay, salt, and butter. Nutritionists fight local beliefs about the dish's merits.

British red squirrels are thriving on an island off the southern coast of England, safe from a deadly poxvirus carried by the more common North American gray squirrel.

Even planets far from an ideal orbit may be habitable because of greenhouse gas warming, a new study shows.

Almost a century after a mysterious explosion flattened a huge swath of Siberian forest, scientists say they have found a crater made by the cosmic object that created the blast.