Seasons
Networks:
Watch Providers:
JustWatch makes it easy to find out where you can legally watch your favorite movies & TV shows online. Visit JustWatch for more information.
S4:E3 Marathon Mouse/Dinosaur Plague/Franklin Chang-Díaz/Space Storms
First Aired: July 14, 2009
Watch how an "exercise pill" turns couch-potato mice into athletes, explore a controversial new theory of what killed the dinosaurs, meet the first Latino-American astronaut, and find out why the beautiful northern lights signal a threat to our electronic society.
