Summary The solar system and its planets seem like a familiar place. Yet scientists now think they've detected something huge lurking in the far reaches of the system we call home. Could it be that a missing, giant ninth planet orbits our sun in the dark reaches of space? We'll meet the astronomers hunting for this hypothetical world. Scientists who are only now beginning to understand how such a massive planet could have ended up so far away from the Sun - way beyond where science predicts planets can form. We join teams in the UK, Germany and the United States who are unlocking the ancient secrets of our planets' past. Only a revolution in our understanding of the Solar System's formation - and a re-assessment of Jupiter's early history - can reveal how Planet 9 was born. Stunning CGI animation will explore the origin or our solar system while dramatic experiments that recreate the micro gravity of space will reveal the secret to the earliest moments of our planets' formation.

• Documentary