Tags: Planet.
2010 TK7 is the first Earth trojan asteroid to be discovered; it precedes Earth in its orbit around the Sun. Trojan objects are most easily conceived as orbiting at a Lagrangian point a dynamically stable location (where gravitational and centrifugal forces balance) 60 degrees ahead of or behind a massive orbiting body in a type of 1:1 orbital resonance. In reality they oscillate (librate) around such a point.
