Season 4

1. Glacier Meltdown

2007-01-31

2. Destructive Forces

2007-02-21

3. Stone Age Apocalypse

2007-02-28

4. Comets

2007-03-07

5. Prehistoric Americans

2007-03-14

6. Deep Space Probes

2007-03-27

Great distances and dangerous environments make robotic spacecraft the best way for scientists to explore our solar system. Acting as our eyes and ears, these probes have revealed secrets about the distant planets and their moons, their surfaces, weather and environments.

7. Dino Meteor

2007-04-12

8. Planet Storm

2007-04-26

9. Polar Apocalypse

2007-04-01

10. Killer Lakes

2007-05-03

Since the death of 1,700 people near a lake in Africa, scientists have uncovered a terrifying series of hazards in lakes across the world.

11. Ring of Fire

2007-08-02

12. Alien Safari

2007-08-09

With advanced technology in their hands, astronomers and scientists may now be capable of detecting extraterrestrial life in the universe. In fact, some think the proof may be found in as little as a decade. Astronomers involved in the effort, including those at SETI (Search for Extraterrestrial Intelligence), discuss the possibilities and the likely spots for finding life outside of Earth.

13. Hyper Hurricanes

2007-10-18

14. Dangers of the Deep

2007-10-25

15. Solar Force

2007-10-30

16. Birth of the Solar System

2007-11-06

Thanks to new developments in the technology of astronomy, scientists have been able to collect new information, giving them clues to how our solar system was formed.

17. Hubble Trouble

2007-11-06