This documentary gives voice to astronomers, these discoverers of comets who share with us their passion for the stars, so close and yet so far from us. In 1994, the comet Shoemaker-Levy hit Jupiter head-on. For the first time, astronomers witnessed live a cosmic collision whose impact force would have destroyed the Earth. To ward off this threat, scientists study the trajectory of asteroids. That of Toutatis, for example, which will brush past our planet in 2004 before quietly passing on its way.