a co-production of the WGBH/NOVA Science Unit and Clear Blue Sky Productions ; written and directed by David Espar and Susan K. Lewis; produced by Linda Garmon
a co-production of the WGBH/NOVA Science Unit and Clear Blue Sky Productions ; written by Joel Olicker and Chris Schmidt ; produced and directed by Joel Olicker
a co-production of the WGBH/NOVA Science Unit and Clear Blue Sky Productions ; written by John Heminway, produced by John Heminway & Michelle Nicholasen
a PBS digital presentation ; a Gemini Productions film for the WGBH/Nova Science Unit and Clear Blue Sky Productions ; written and directed by Gail Willumsen ; produced by Jill Shinefield, Gail Williamson