The International Space Station regained contact with NASA controllers in Houston after nearly three hours of accidental quiet, the space agency says.

Officials say the six crew members and station are fine and had no problem during the brief outage.

What do pine cones and paintings have in common? A 13th century Italian mathematician named Leonardo of Pisa.

Better known by his pen name, Fibonacci, he came up with a number sequence that keeps popping up throughout the plant kingdom, and the art world too.

Scientists have discovered a 200-kilometer-wide (125-mile-wide) impact zone in the Australian outback they believe was caused by a massive asteroid smashing into Earth more than 300 million years ago.

Andrew Glikson, a visiting fellow at the Australian National University, said the asteroid measuring 10 to 20 kilometers in diameter was a giant compared to the plunging meteor that exploded above Russia a week ago.

The number of African elephants killed by poachers in 2012 will most likely be higher than the 25,000 illegally killed the previous year, the head of U.N. wildlife trade regulator CITES said Tuesday.

"Right across the range of the African elephant, in 2011 25,000 elephants were illegally killed, and based upon our analysis done so far, 2012 looks like the situation deteriorated rather than improved," said CITES Secretary General John Scanlon.

Police in Pakistan are seeking nine men who illegally killed an endangered markhor goat in a national park, officials said Tuesday.

A police case has been registered against the hunters after they killed the markhor in the Chitral Gol National Park in northern Pakistan, close to the Afghan border on Monday, wildlife officials said.

NASA, universities and private groups in the U.S. are working on asteroid warning systems that can detect objects from space like the one that struck Russia last week with a blinding flash and mighty boom.

But the U.S. space agency reiterated that events like the one in the Urals, which shattered windows and injured nearly 1,000 people, are rare.

With scant snowfall and barren ski slopes in parts of the U.S. Midwest and Northeast the past couple of years, some scientists have pointed to global warming as the culprit.

Then, when a whopper of a blizzard smacked the Northeast with more than 2 feet (0.6 meters) of snow in some places earlier this month, some of the same people again blamed global warming.

Ruby-throated hummingbirds are migrating to North America weeks earlier than in decades past, and research indicates that higher temperatures in their winter habitat may be the reason.

Researchers say the early arrival could mean less food at nesting time for the tiny birds that feed on insect pests, help pollinate flowers and are popular with birdwatchers.

Mussels secrete a powerful adhesive to hold tight on rocks swept by violent waves -- and a synthetic version could prove critical for surgery and cancer treatment, researchers said Saturday.

Scientists have created materials that mimic the mussels' sticky proteins and could have medical applications such as sealants for fetal membrane repair, self-setting antibacterial hydrogels and polymers for to deliver cancer drugs and destroy cancer cells.

For decades, the strange substance called dark matter has teased physicists, challenging conventional notions of the cosmos.

Today, though, scientists believe that with the help of multi-billion-dollar tools, they are closer than ever to piercing the mystery -- and the first clues may be unveiled just weeks from now.