Russian scientists on Saturday dismissed initial reports that they had found a wholly new type of bacteria in a mysterious subglacial lake in Antarctica.

Sergei Bulat of the genetics laboratory at the Saint Petersburg Institute of Nuclear Physics had said Thursday that samples obtained from the underground Lake Vostok in May 2012 contained a bacteria bearing no resemblance to existing types.

A rough, whitish block recovered from an Elizabethan shipwreck may be a sunstone, the fabled crystal believed by some to have helped Vikings and other medieval seafarers navigate the high seas, researchers say.

In a paper published earlier this week, a Franco-British group argued that the Alderney Crystal — a chunk of Icelandic calcite found amid a 16th century wreck at the bottom of the English Channel — worked as a kind of solar compass, allowing sailors to determine the position of the sun even when it was hidden by heavy cloud, masked by fog, or below the horizon.

Japanese scientists have produced 26 generations of clones from a single mouse, the lead researcher said Friday, possibly paving the way for the mass replication of valuable livestock.

The team have so far produced 598 mice that are genetic copies of one original creature in an experiment that has so far been going for seven years, said Teruhiko Wakayama of the Riken Center for Developmental Biology.

A fifth of Canada's glaciers could be gone by the end of the century, a casualty of global warming that would drive a 1.4-inch (3.5-centimeter) rise in sea levels, a study found Thursday.

"Even if we only assume moderate global warming, it is still highly likely that the ice is going to melt at an alarming rate," lead author Jan Lenaerts said in a statement.

The face of Mars is dotted with a maze of channels, pointing to possible ancient megaflood episodes.

Now scientists peering below the surface have uncovered the first evidence of underground channels apparently created by flooding — a finding that's expected to further illuminate the role of water in Mars' history.

Talk about a caffeine buzz: A new study says honeybees get a shot of caffeine from certain flowers, and it perks up their memory.

That spurs them to return to the same type of plant, boosting its prospects for pollination and the future of the plant species.

A new study looking at 11,000 years of climate temperatures shows the world in the middle of a dramatic U-turn, lurching from near-record cooling to a heat spike.

Research released Thursday in the journal Science uses fossils of tiny marine organisms to reconstruct global temperatures back to the end of the last ice age. It shows how the globe for several thousands of years was cooling until an unprecedented reversal in the 20th century.

A rare bright comet shows up in the northern hemisphere this week, cruising past Earth with promise of spectacular naked-eye viewings of the giant ball of ice and dust streaking the twilight sky with a blazing tail.

Dubbed Pan-STARRS after the Hawaii-based telescope that first spotted it nearing our corner of the universe, the comet should be at its brightest from about Friday to the middle of next week, say astronomers.

Indonesia scientists say they are closely monitoring a smoking volcano on Java island, urging villagers and tourists to stay off the mountain's slope.

Government volcanologist Hendra Gunawan said Thursday that Mount Tangkuban Perahu in West Java province shot up smoke and ash nearly 500 meters (1,640 feet) into the air since Monday, and was placed at the second-highest alert level.

The subatomic particle whose discovery was announced amid much fanfare last year, is looking "more and more" like it could indeed be the elusive Higgs boson believed to explain why matter has mass, scientists said Wednesday.

But in the latest update, physicists told a conference in La Thuile, Italy, that more analysis is needed before a definitive statement can be made.