Horizon 2014-2015 Episode 7 Secrets of the Solar System ( Air Date 2015-03-03 ) Genre Documentary category. Overview "New planets are now being discovered outside our solar system on a regular basis, and these strange new worlds are forcing scientists to rewrite the history of our own solar system. Far from a simple story of stable orbits, the creation of our solar system is a tale of hellfire, chaos and planetary pinball.".