Season 4

Join astronomers hunting for Earth-like planets, see how computers distinguish authentic art from forgeries, meet a spider biologist who studies sexual cannibalism, and learn about genes that may be involved in causing autism.

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.

Discover why picky eaters may have a genetic excuse, learn about a new strategy for capturing carbon dioxide from the atmosphere, see just how intelligent marine mammals can be, and meet a biomedical engineer who has figured out a way to make tiny livers in her lab.

Follow a NASA satellite looking for water on the moon, see what ancient salt deposits reveal about life 250 million years ago, learn how bird brains are remarkably similar to our own, and meet a climatologist who digs for clues to climate change in the world's highest glaciers.

Explore the controversies behind genetic testing and genome sequencing, learn about algae fuel, follow an expedition to the Arctic Ocean seafloor, and meet a woman engineer designing prosthetic limbs controlled by human thought.

Get an astronaut's view of the Hubble repair mission, find out why cowbirds are called "gangster birds," meet a Mexican immigrant farmworker-turned-brain surgeon, and learn how neuroscientists are finding ways to erase memories.

Using new data from cave stalagmites and the Mississippi riverbed to understand how and why earthquakes strike in the heartland; the crucial role sleep plays in strengthening memories and facilitating learning; a profile of marine geologist Sang-Mook Lee; paleontologist Jonathan Bloch, who thinks that tiny bones embedded in limestone may be the evolutionary evidence of the creatures that evolved into primates.