The season opener examines artificial diamonds that are indistinguishable from the real "girl's best friend"; how researchers determined the source of the anthrax used in the 2001 anthrax attacks; the pitch-correction software Auto-Tune. Also: a profile of computer scientist Luis von Ahn (Carnegie Mellon), who trains computers using games and developed ReCAPTCHA to decipher unidentified words in digitalized books.
The search for Earth-like planets using the Kepler telescope; neurologist Rudy Tanzi's efforts to discover the cause of autism; whether a computer can identify a forged painting; biologist Maydianne Andrade's studies of the Australian redback spider (the female eats the male after mating).
Drugs that may aid children with muscular dystrophy; the northern lights. Also: paleontologist George Poinar, who's discovered clues about parasitic pandemics that may have decimated the dinosaurs; rocket scientist-astronaut Franklin Chang-Diaz.
The sense of taste; synthetic trees that can cleanse the air of carbon dioxide; what the study of walruses and sea lions reveals about the evolutionary roots of human language. Also: medical engineer Sangeeta Bhatia, the director for multi-scale regenerative technology at MIT, is profiled.
A team of NASA scientists who are studying how to build a permanent base on the moon; the role that the zebra finch, an Australian songbird, played in understanding the neuronal processes behind sound. Also: microbiologist Jack Griffith, who discovered the oldest known organic molecules on Earth; climate scientist Lonnie Thompson.
The implications of personal genetic profiles, which predict the likelihood of people contracting serious diseases; a Texas algae farm where researchers work to turn algae into biofuel; Gakkel Ridge, which lies deep beneath the Arctic Ocean. Also: roboticist Yoky Matsuoka is profiled.
The 2009 mission to repair the Hubble space telescope, which required intensive spacewalks; the whys of the cowbird, which lays its eggs in other birds' nests. Also: a profile of Dr. Alfredo Quiñones-Hinojosa, a Johns Hopkins neurosurgeon who illegally entered the U.S. in 1987 in search of farm work; and the story of Henry Molaison, who suffered severe short-term memory impairment after having part of his brain removed during an experimental procedure to stop severe epileptic seizures.
How and why earthquakes occur in the heartland; the role sleep plays in memories and learning; paleontologist Jonathan Bloch's search for the pre-primate missing link. Also: South Korean geophysicist Sang-Mook Lee, who is paralyzed from the neck down, is profiled.