Asteroid Has Been Following Us for Thousands of Years So-called trojan asteroid discovered in Earth's orbit By Mark Russell, Newser Staff Posted Jul 28, 2011 9:22 AM CDT 4 comments Comments This artist's concept provided by NASA illustrates the first known Earth Trojan asteroid, discovered by NEOWISE, the asteroid-hunting portion of NASA's WISE mission. (AP Photo/NASA - Paul Wiegert) (Newser) – It turns out that Earth has another neighbor besides the moon: a so-called Trojan asteroid that has been traveling with us around the sun for thousands of years, reports the Los Angeles Times. Plenty of other planets have their own asteroids—there are at least 4,000 in Jupiter's orbit alone—but scientists were never able to find any around the Earth, in part because the sweet spot where asteroids could exist was hidden by the brightness of the sun. But an astronomer from Alberta thought to use NASA's Wide-Field Infrared Survey Explorer, a space-based telescope that can point its lens at a 90 degree angle to the sun—and it did indeed find such an asteroid. Should scientists be able to find others, NASA may have itself a candidate for a visit by astronauts, a feat it's looking to attain in as little as 15 years. A scientist who wasn't part of tracking down this Trojan explains that the newly discovered asteroid isn't suitable for a visit because it's too tilted in relation to the solar system.