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DISCOVERY Asteroid, Earth Share Same Orbit The asteroid is shown in gray and its extreme orbit is shown in green. (Paul Wiegert, NASA / AP Photo)

Asteroid, Earth Share Same Orbit

NASA has recently discovered that Earth shares its orbit around the Sun with a small "Trojan" asteroid, which is just 300 meters (984 feet) in diameter, but owes its distinct name to its stable spot either directly behind or in front of Earth. Since they share the same orbit, there is no risk that the Trojan will ever collide with Earth—or at least not any time soon. According to the author who published a study on the discovery, the asteroid's orbit is "stable for at least 1,000 years," and will remain at least 15 million miles away from Earth for the next 100 years.

July 28, 2011 8:19 PM