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.

Most animals leave their home turf when they reach adulthood to avoid competing with relatives. But here's an exception: More than three decades of dogged research shows that prairie dogs are more likely to disperse when all of their family members are gone.

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.

Our short Argentine Invasion traces the relentless and bloody march of a band of ant warriors whose empire now wraps around the planet (they've been found on every continent except Antarctica). Adam Cole charts their impressive path to global ant dominance in a stylish graphic.

No word yet on whether memorizing The Cat in the Hat will now become a requirement for medical school admission.

The U.N. says today symbolically marks the moment when the world's population reaches 7 billion. A little more than two centuries ago, the global population was 1 billion. How did it grow so big so fast? With the help of a sound montage and video, it gets a bit easier to see how the Earth can produce that kind of a crowd.