“Christmas Out of the Box” (8 p.m., National Geographic) lends a scientific veneer to a whimsical exploration of Christmas fantasies. “Experts” ponder the power and thrust needed to send a big man in a sleigh on a global trek and the physiology of reindeer noses. Others speculate on the origins of the star of Bethlehem.

More down-to-earth discussions explore ways the seasonal demand for toys and presents has turned a religious holiday into a $450 billion Christmas Industrial Complex.

¢ On a similar if not holiday-specific theme, “Sweet Tooth” (9 p.m., National Geographic) explores the ongoing business battle for candy-and-confection supremacy. Just how do they get that white goop into every Twinkie? How has Peeps processing technology evolved over the decades? How do humble jellybeans survive the cutthroat candy competition?

¢ Liam Neeson narrates “CNN Presents: After Jesus – The Earliest Christians” (6 p.m., CNN). The special explores the growth of Christianity in its first four centuries from that of a tiny sect in a far-off province to the established religion of the late Roman Empire. How did the faith evolve over centuries of persecution to become the predominant religion of the Western world?

Holiday highlights

Gluttons for holiday movies, good, bad and awful have only five more days to feast. Here’s tonight’s menu.

¢ Patrick Stewart stars in the 1999 adaptation of “A Christmas Carol” (7 p.m., TNT).

¢ A boorish divorced man (Jay Mohr) is doomed to repeat the holiday in the comedy “Christmas Do-Over” (7 p.m., Family).

¢ A loving aunt (Sean Young) wants to take in orphaned kids “Home for the Holidays” (8 p.m., Lifetime).

¢ A publishing phenomenon (Rob Lowe) turns into a Scrooge in the fantasy “A Perfect Day” (9 p.m., TNT).

Tonight’s other highlights

¢ Doug adopts a dog on “King of Queens” (7 p.m., CBS).

¢ Fred Astaire dances on the ceiling in the 1951 musical “Royal Wedding” (7 p.m., TCM).

¢ A sicko has a sordid auction on “Criminal Minds” (8 p.m., CBS).

¢ Scheduled on “Dateline” (8 p.m., NBC): a fatal workplace shooting.

¢ Scheduled on “Primetime” (9 p.m., ABC): basic instincts.

¢ Stephen Colbert engages in a musical feud with the Decemberists on “The Colbert Report” (10:30 p.m., Comedy Central).