When the summer solstice arrives Wednesday, it will mark six months until the winter solstice on Dec. 21, when, according to some people's reading of the Mayan Long Count calendar, the world will be destroyed.
Scientists and archaeologists have debunked the doomsday theory, but it remains alive and well in popular culture.
"People who are not specialists in the Maya calendar have taken a few quotes and a few misunderstandings by scholars, and they've picked it up and run with it," says Simon Martin, co-curator of a "Maya 2012: Lords of Time" museum exhibit in Philadelphia. "So it becomes somewhat unrecognizable."
In 2009, the movie "2012" destroyed the world in the best special-effects fashion. The cable channel Spike TV has announced a new reality show called "Last Family on Earth," in which one of the prizes is a spot in an underground bunker provided by Vivos, a company that sells space in such shelters. Vivos maintains a countdown clock on its website.
Striking a more positive note, the online stock trading firm Ameritrade suggests, "Say the sun rises on December 22, and you still need to retire. Ameritrade consultants can help you build a plan that suits your life."
The source of the current fear apparently is the end of the cycle of the Mayan Long Count calendar, one of the Mayans' many calendars. The Mayan culture in Middle America thrived for six centuries before collapsing around A.D. 900, according to recent scholarship, because of a series of droughts and possibly warfare. The Mayans were sophisticated calendar makers and time keepers; in Guatemala recently, a Mayan mural with calendar calculations etched on the walls was discovered.
Kate Quinn, director of the University of Pennsylvania Museum of Archaeology and Anthropology, or the Penn Museum, where the "Lords of Time" exhibit was displayed, says that the previous end date on the Mayan Long Count calendar occurred 5,125 years ago and was regarded as a significant event.
Martin, co-curator of the exhibit, says that because of different correlations of dates, there is some dispute over when the Mayan Long Count calendar actually will end this time. He said you might want to wait until Dec. 25 to be in the clear.