The asteroid, which follows Neptune's orbit around the sun, ...classified as a Trojan, was found in a difficult-to-detect area near Neptune, known as the Lagrangian point L5. Lagrangian points are five areas in space where the gravitational tugs from two relatively massive bodies -- such as Neptune and the sun -- balance out. This allows smaller bodies, like asteroids, to remain stable and fixed in synch with the planet's orbit, as they orbit the sun... Trojan asteroids have previously been found in some of the stable points near Neptune and Jupiter, but this is the first discovery of a Trojan...