The SCI FI Channel begins airing the second series of the revamped Doctor Who, starring David Tennant in place of Christopher Eccleston, tonight at 8PM ET with “The Christmas Invasion” followed by “New Earth” at 9:30PM. Update: Time correction, plus I forgot to mention that Who has been listed in the Guinness Book of World Records as the TV’s longest-running sci-fi show, although there is some confusion about Stargate SG-1 entry as “Longest running sci-fi TV show (consecutive)”. Doctor Who ran for 26 “consecutive” years. Guinness either means currently in production, or (my theory) that the writer’s strike in 1980 that cancelled “Shada” is considered a break, and the number and length of episodes back then resulted in the total produced time being less than what SG-1 has. Anyone want to do the maths?