(CNN)-A prediction with origins in the Mayan civilization has some people convinced the world is about to end. Steve Pace has been prepping for the end of the world for years.
"I foresee the potential for a disaster that is catastrophic."
CNN caught up with him in 2009 as he prepared with food, weapons, even anti-radiation pills all for this year, 2012. Pace is among the Doomsdayers worried that December 21st 2012 will be the last. That's the day when the ancient Mayan calendar is said to end.
But that talk of the end of the world is sheer nonsense, says top scientists. In a YouTube video that NASA put out, experts explain why it's just another day. Their scientists take all of the rumors one by one and debunk them.
For example, one theory is that the planets will somehow align, causing devastating tidal effects. Two problems there : there is no planetary alignment taking place and even if it were only the moon and the sun could have effect on tides on the earth, says NASA.
More info: NASA Doomsday Fact Sheet