TODAYshow.com's Dara Brown talks with author and professor Gerardo Aldana about his theory that the Mayan calendar, which many believe indicates that the world will end in 2012, is wrong.

2012 and Maya prophecies: What were they thinking?

The statement said the "story" started with claims by the ancient Sumerian civilization that a "supposed planet" called Nibiru was headed toward Earth.

"This catastrophe was initially predicted for May 2003, but when nothing happened the doomsday date was moved forward to December 2012 and linked to the end of one of the cycles in the ancient Mayan calendar at the winter solstice in 2012 -- hence the predicted doomsday date of December 21, 2012," NASA said.

Maya text cites 2012 as end of calendar cycle, not end of world

"Just as the calendar you have on your kitchen wall does not cease to exist after December 31, the Mayan calendar does not cease to exist on December 21, 2012," it added. "This date is the end of the Mayan long-count period but then -- just as your calendar begins again on January 1 -- another long-count period begins for the Mayan calendar."

More world stories from NBC News:

• EXCLUSIVE: US behind Afghan 'insecurity,' Karzai says
• Sex mobs target Egypt's women
• Researchers: North America least likely region for terrorism
• Africa's lion population plummets, study finds
• North Korea pays tribute to Kim Jong Il's 'threadbare' parka
• ANALYSIS: Egyptians warn Morsi is no friend of US
• Bread and expired milk: School lunch scandal sparks outrage in China
• Experts: Antarctica, Greenland ice melting into sea