disc 1. Catastrophes that changed the planets ; Nemesis: the Sun's evil twin ; How the solar system was made ; Crash landing on Mars. disc 2. Worst days on planet Earth
God and the Universe ; UFOs, the real deal ; How big, how far, how fast ; disc 3. Our place in the Milky Way ; Alien sounds
disc 3. Deep freeze. gdisc 4. Microscopic universe ; Ride the comet ; When space changed history.
