In the video, which was posted online Wednesday (Mar. 7), Don Yeomans, head of the Near-Earth Objects Program Office at NASA/JPL, explains away many of the most frequently cited doomsday scenarios.
Addressing the belief that the calendar used by the ancient Mayan civilization comes to a sudden end in December 2012, and that this will coincide with a cataclysmic, world-ending event, Yeomans said: "Their calendar does not end on December 21, 2012; it's just the end of the cycle and the beginning of a new one. It's just like on December 31, our calendar comes to an end, but a new calendar begins on January 1." Yeomans also attempted to allay fears regarding potential causes of a Mayan apocalypse, including Nibiru, an imaginary planet that some people think is swinging in from the outer solar system just in time to collide with Earth in December.
"This enormous planet is supposed to be coming toward Earth, but if it were, we would have seen it long ago. And if it were invisible somehow, we would have seen the [gravitational] effects of this planet on neighboring planets. Thousands of astronomers who scan the sky on a daily basis have not seen this," he said. [Video: NASA Debunks Doomsday Theories]
He added that there is zero possibility of a NASA cover-up. "Can you imagine thousands of astronomers who observe the skies on a daily basis keeping the same secret from the public for several years?" As for solar flares, Yeomans explained that these do exist — in fact, two massive solar flares erupted just days ago, sending bursts of solar radiation into space — but they are part of the sun's normal 11-year cycle. Radiation from solar flares can damage orbiting satellites, but Earth's magnetosphere shields its inhabitants from the blasts, and the flares are not a health concern.
"Then we have planetary alignments," Yeomans said. Some doomsayers believe the other planets and the sun will align with the Earth in December and cause catastrophic tidal effects.
"Well, first of all, there are no planetary alignments in December of 2012, and even if there were, there are no tidal effects on the Earth as a result. The only two bodies in the solar system that can affect the Earth's tides are the moon, which is very close, and the sun, which is massive and also fairly close. But the other planets have a negligible effect on the Earth."
(Incidentally, it is perfectly normal for the sun and moon to align, bolstering each other's gravitational pulls on Earth and generating higher-than-normal ocean tides. This happens twice each month.)
Addressing the claim that Earth's axes are going to shift on Dec. 21, 2012, he said: "The rotation axis can't shift because the orbit of the moon around the Earth stabilizes it and doesn't allow it to shift."
Yeomans noted that the magnetic field does shift every half-million years or so, but "there's no evidence it's going to happen in December, and even if it were to be shifting, it takes thousands of years to do so. And even if it did shift, it's not going to cause a problem on the Earth apart from the fact that we're going to have to recalibrate our compasses."
Invoking the astronomer Carl Sagan's famous maxim, he said: "Extraordinary claims require extraordinary evidence. Since the beginning of time there have been literally hundreds of thousands of predictions for the end of the world, and we're still here."