Sean Spicer, the RNC's Communications Director, referred to the end of the Mayan calendar on Dec. 21. Doomsday theories have evolved around this date, suggesting the ancient culture knew the world would end then.

The National Aeronautics and Space Administration (NASA) has  received thousands of letters expressing far-reaching concern about the possible "end of the world," prompting the agency to respond by reassuring people that the Internet is full of "false rumors."

NASA posted on their website's Frequently Asked Questions section:

The world will not end in 2012. Our planet has been getting along just fine for more than 4 billion years, and credible scientists worldwide know of no threat associated with 2012.

NASA has also explained that while the Mayan calendar "ends" on Friday, it does not cease to exist. NASA compared the event to the end of a year in modern terms, when most families must get a new calendar to start counting down another year. 

As for Spicer, if he hasn't started his Christmas shopping yet, he might want to take a good look at that calendar now.