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Scientists are always looking for a more accurate answer to the question, "What time is it?" Now they've built the most precise atomic clock yet — but it's not just telling time. It has the potential to investigate the accuracy of the General Theory of Relativity.

The program is part of a national push for science education among minorities. A U.S. Department of Commerce study found that blacks and Latinos are half as likely as whites to have a job in science or engineering.

The dose of radiation an astronaut would experience on a trip to Mars is higher than the annual limit set for workers at nuclear power plants. But Mars enthusiasts say the radiation threat isn't high enough to cancel the trip.

Our closest relatives, chimpanzees and gorillas, breast-feed their offspring for several years. Some baby orangutans nurse until they are 7 years old. Researchers found a way to test ancient teeth for clues about when humans cut nursing short.

Scientists have discovered water that was sealed in Canadian bedrock for nearly half of Earth's history. It may contain the descendants of ancient microbes. The discovery could give scientists new insights into early life on Earth and inform the search for life on other planets.

Millions of basketball fans will fill out NCAA tournament brackets this week and try to correctly predict the outcomes of every game. The chances of succeeding are about 1 in 150 quintillion. A group of computer scientists are trying to beat those odds by writing programs that learn to pick winners.

For more than a century, neurons have been the superstars of the brain. Now researchers say that when they placed human versions of another type of brain cell into mice brains, the mice grew up to be faster learners. This supports the hypothesis that these glial cells — and not just better-known neurons — play an important role in learning.

Bees and flowers communicate in colors, scents and shapes. Now scientists have discovered that bumblebees can also sense flowers' electric fields. This sixth sense helps them remember and recognize nectar-rich blooms while foraging.

In New Jersey, thousands of discarded Christmas trees have dodged the wood chipper and hit the beach instead. They're being used to jump-start new dunes, but scientists warn that these man-made dunes could be less sturdy than dunes that form naturally.

What killed the dinosaurs? It's history's ultimate murder mystery, and for decades the prime suspect has been a giant asteroid. New data suggest that it struck right before the extinction. But scientists say it still may not tell the full story of what happened to the dinosaurs.