Earth Has an Orbital Companion Stuck in a Horseshoe-Shaped Orbit Around the SunLargest horseshoe companion knownBy Clay Dillow
Near-Earth asteroids aren’t all that rare, but today two researchers at Armagh Observatory in Northern Ireland say they’ve found an extremely rare near-Earth object in an orbit very similar to Earth’s. Asteroid 2010 SO16 is not exotic because of it’s closeness to the home planet, but because it is stuck in a rare horseshoe orbit.
Horseshoe orbits only happen under a specific set of circumstances, so it is believed they are pretty rare. The name “horseshoe” is derived from the shape of the object’s orbit as seen from Earth--that is, it doesn’t stop mid-orbit, turn around, and travel in the other direction. It has everything to do with shifts in the object’s orbital path and our perspective of the object as it gets closer, shifts orbit, and then gets further away without ever passing Earth.