Season 3, Episode 5 Leeches; SETI; Edith Widder

First Aired: July 23, 2008

Leeches, bloodsuckers with a bad reputation; the Allen Telescope Array, a project that searches for intelligent life elsewhere in the universe; creating embryonic-like stem cells from adult skin cells; marine-bioluminescence specialist Edie Widder, who developed a camera system that uses a light wavelength that's invisible to sea creatures.