If modern-day Mayans aren't worried about an apocalypse occurring on Dec. 21, why should you be?

While there are a fair number of spiritualists, preachers, doomsday preppers and pundits keen to cry apocalypse, there's a notable lack of Mayans trumpeting the so-called prophecy -- probably because it isn't even a prophecy. Dec. 21 is basically when the Maya calendar flips to a new page. The end of a cycle can be superficially compelling but rarely spells actual doom -- Earth survived Y2K, after all, and your calendar doesn't automatically explode on New Year's Eve.

In Mexico, where many of the modern-day Maya live, most of the hubbub centers around accommodating the flood of tourists that are flocking to ancient ruins in anticipation of Friday.

Jose Manrique Esquivel, a resident of the Yucatan peninsula and a Maya descendent, told the Associated Press that his community was planning to celebrate in the coming days.

"For us, this Dec. 21 is the end of a great era and also the beginning of a new era. We renew our beliefs. We renew a host of things that surround us," Esquivel said.

Rather than preparing for an apocalypse, many modern Maya are using Dec. 21 as a chance to call for environmental responsibility.

"We're putting in danger the existence of our world," Esquivel told the Associated Press. "It's our goal for this date to create consciousness about our Earth. We want to say to everybody that the Maya live and we want to gather our strength to save the Earth."

Modern Maya and scholars emphasize that the so-called Mayan apocalypse prophecy stems from a misreading of a way that the Maya measured time called the Long Count calendar. This complex rotating calendar, used by a number of Mesoamerican societies, uses a number system based on powers of 20 and includes subdivisions called bak-tuns that are units of 144,000 days.

In Maya theology, Earth was created in 3114 B.C., a date that on the Maya Long Count calendar is written as This year, on Dec. 21 -- though some scholars dispute whether this is the right date or not -- the calendar will turn over like a car's odometer, back to, marking that passage of 13 bak-tuns.

No archaeological evidence points to any belief that this calendar change held any particular apocalyptic significance for the Maya.

“There will be another cycle,” E. Wyllys Andrews, the director of Tulane University's Middle American Research Institute, told Tulane's news service in 2008. “We know the Maya thought there was one before this, and that implies they were comfortable with the idea of another one after this.”

NASA is so sure that the world isn't going to end that the space agency has already posted a news item scheduled for Saturday, titled “Why the World Didn't End Yesterday.” The agency also maintains a page dedicated to debunking some of the more popular rumors about the end of the world.

Some end times enthusiasts have linked Dec. 21 to a story about a planet called Nibiru that will crash into Earth.

“If there were anything out there like a planet headed for Earth," NASA astrobiologist David Morrison says in a statement, "it would already be [one of the] brightest objects in the sky. Everybody on Earth could see it. You don't need to ask the government -- just go out and look. It’s not there.”