For eons, the Awash River in eastern Africa's Great Rift Valley has drawn so many humans and other animals that the valley is considered a picture window on evolution.

» Roots of human fossil tree deepen

Politically, Taiwan's relationship to Beijing could be characterized as a rift born of defiance on one side and menace on the other. But geologically, the small island of Taiwan appears to be on a collision course with mainland China.

The spectacular images of the deep reaches of the universe are everywhere these days, from posters to postage stamps.

Are the footprints of surprisingly ancient Americans preserved in 40,000-year-old volcanic ash in southern Mexico? In December, an article in the journal Science cast a cloud of doubt over that claim.

Home fires kill several thousand people a year in the United States. Only half of these fires occur during the night, and the chance of death is related more to whether the victim is asleep than whether the fire occurs during the day or night.