DOCUMENTARY WATCH

Fireballs From Space

World, 9pm

This astronomical detective story takes an exhilarating ride aboard asteroids, comets and other celestial bodies that cross Earth's orbit and, some say, threaten our very existence. From the meteor thought to have killed the dinosaurs 65 million years ago to the fiery comet Shoemaker-Levy 9 that ploughed head-on into Jupiter, computer animation shows how these fireballs form and what happens when they explode in space or collide with immovable objects. See how space agencies are working to prevent a disastrous impact, and go behind the scenes of a Nasa project that, for the first time, orbited and landed a satellite on an asteroid.