It's unclear what will end the world on Friday -- a zombie attack, possibly a collision with a rogue planet -- but doomsday prophets nationwide all agree: Our time is up.

Or not.

NASA scientists have taken to the Internet to let the world know that we are, in fact, safe from all zombies, black holes, supernovas and other threats to humanity -- despite an ancient Mayan claim that the world would end on Dec. 21, 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 scientists said.

The long-awaited end of days coincides with the end of the Mayan calendar, at a date that translates to That date is mentioned twice in Mayan manuscripts, though scholars dispute that it marks the end of mankind. They aren't the only ones who think the theory is far-fetched.

The New York-based oddsmaker put the odds of the world ending Friday at 300 million to 1. That means someone is more likely to win the Powerball lottery jackpot (175 million to 1), witness Michael Jordan's return from retirement (50 million to 1) and see the Chicago Cubs win the World Series next year (1,500 to 1) than die in the apocalypse.

Despite the long odds, Americans are adjusting their plans just in case. Craigslist advertisers have sought passage on any ark being built or, at least, a date. "In case of lava swirling at our feet, I'm 6'1" so you can stand on my shoulders and buy yourself a few more minutes," one poster wrote.

In France, people are flocking to the town of Bugarach because they believe they'll be spared if they can get to a nearby mountain they consider sacred.

Still, many Washington-area bars are unfazed by impending doom and have planned apocalypse-themed events to help people go out with a bang.

Even if the world isn't wiped out Friday, it would be too soon for mankind to celebrate its survival. Archeologists were only able to loosely translate the Mayan calendar. That means they've narrowed the date of global doom down to three dates, Dec. 21, 23 and 24.

Doomsday prophets all latched on to Dec. 21 as the day the world will end because "they could tie it to the winter solstice," said Walter Witschey, an expert of ancient Mayan culture and professor at Longwood University. Regardless, the world probably won't end on Dec. 23 or 24 either, he said.

"The Maya themselves in ancient times ... and even the modern Maya don't ever claim that the world will end [this month]," Witschey said.