While the enormous interest in 2012 prophecies that has been gathering for some time strongly suggest that something momentous will happen in that year that affects the whole world, permanently changing everything, some of the things prophesied for that year will not happen, because they can't, and others are non-issues, trivial and not worth bothering with. There may be enormous mass fires scrubbing whole counties clean; 1,000-year floods that wash away entire towns or even cities (as witness the current situation in Cedar Rapids, Iowa); giant tornadoes up to half a mile wide, perhaps carrying tons of burning material, ripping up the Midwest as it goes; Category 8 hurricanes; 9.5 earthquakes; a dinosaur-killer asteroid or comet impacting the Earth; mile-high tsunamis; nuclear war; killer pandemics; mass sterility among ourselves or our farm animals or cultivars; mass insanity, ditto -- the list of possibilities is endless. But some things can't happen, and others are at bottom ho-hum affairs. Here's the short list:

1) Pole shift: Some commentators on 2012 prophesy a rapid shifting of the Earth's poles of rotation, "rapid" meaning that a shift of more than 20 degrees of inclination takes place within a week or less. Have we forgotten torque and angular momentum, folks? When the axis of a rotating body shifts its inclination by a significant amount, which can be as little as one degree, that means its angular momentum changes.

In physics, the angular momentum of an object rotating about some reference point is the measure of the extent to which the object will continue to rotate about that point unless acted upon by an external torque. In particular, if a point mass rotates about an axis, then the angular momentum with respect to a point on the axis is related to the mass of the object, the velocity and the distance of the mass to the axis (http://en.wikipedia.org/wiki/Angular_momentum). A torque (τ) (also called a moment) is a vector that measures the tendency of a force to rotate an object about some axis (center). The magnitude of a torque is defined as the product of a force and the length of the lever arm (radius). Just as a force is a push or a pull, a torque can be thought of as a twist (http://en.wikipedia.org/wiki/Torque). The heavier a rotating body is, the greater its angular momentum, and the more torque is required to force its axis of rotation to change. Torque is a force, or mass x accelaration, where in this case accelaration is a change in either the angular velocity of the body or its axis of rotation, or both. You can see this easily in the form of a car being braked to reduce its speed or bring it to a stop. The friction of the brake shoe against the mechanism that turns the wheel does the job, and the faster the wheel is turning, the harder the brake shoe must be applied to slow it down or halt its action. Friction generates heat -- drag your shoe along the ground and touch the surface where it contacts the earth, or brake a turning wheel and touch the wheel right afterward, and you can feel extra heat.

What this translates to is that to change the Earth's axis of rotation within a few days would take an enormous force, and given how large the Earth's mass is, that means the heat released by that change would be enough to slag the Earth's crust right down to the mantle. It could only happen once, and after that there would be at most a glowing incandescent ball of non-living matter -- or maybe just a great pile of white-hot rubble -- cruising through space where the living Earth had once been. In either case life, including humans as well as any other, would no longer exist on Earth, and never would again. Yet those who prophesy this "pole shift" seem to believe it has happened again and again during Earth's long history. It is claimed that Einstein predicted a pole shift. Well, so what? The Earth's rotation axis may in fact have shifted a few times in its history, but if so, each of those shifts took place over millions of years, and were due to a geometrical imbalance in the positions of the continental masses around the globe. Even that is unlikely, though there is some wiggle-room for thinking it might have happened. That Einstein supposedly predicted pole shifts means either that he was referring to long, slow shifts for geological reasons, or that he didn't know what the hell he was talking about. A man can be brilliant in some areas and a normal clod like the rest of us in others, and this was as true of Einstein as anyone else. That is the normal lot of us all, talent in one or more areas, less than stellar performance in others. So it was with Einstein. Unlike his Special and General Theories of Relativity, the idea of a pole shift, even over long, long periods of time, remains to be proven out, so we'll have to wait on that one. But when it comes to a pole shift of mere days, we can say with certainty that no, it won't happen. Not even once. The continued existence of our planet as a living world testifies to that.

2) The giant planet/brown dwarf "Nibiru" entering the inner Solar System and wreaking havoc: Supposedly over the last few decades a large body invisible in visible-light wavelengths but evident to infrared detectors has been plummeting into the inner Solar System from the Oort Cloud of comets that is the outer bound of the Solar System, a light-year or more out from the Sun. According to this prophesy, "Nibiru" moves in a tremendously elongated ellipsoidal orbit around the Sun, one focus around the Sun, another somewhere in the Oort Cloud. If such a body were to travel from the Oort Cloud to the inner Solar System in anything under a few tens of millennia, it would have to have been fired from a cosmic cannon of some sort -- otherwise it would have enjoyed a slow, majestic journey to our neck of the Solar neighborhood with consequences that would have been noticed by every people on Earth over the last many centuries, strongly perturbing the orbits of whatever gas giants, ice giants, and other bodies lying along its route of march as it went. It would have precipitated comets and asteroids along that route into the inner Solar System, as well, heralds of approaching doom many of which would have peppered Earth and Moon with bolide strikes, leaving the Earth looking like a cosmic dart-board, with few, if any, living creatures left alive on it afterwards. And all the planets along its journey would have been thrown into chaos, some of them possibly being sent on a sunward death plunge ending in their being swallowed up by the Sun, giving rise to Solar Storms that would have fried any remaining inner planets to a crisp. On top of that, supposedly "Nibiru" repeats this dance of death every fifty million years. The Earth is four and a half billion years old -- a hundred times more than "Nibiru's" orbital period -- and there is no sign at all that such a thing has ever happened to the Earth and the rest of the Solar System in all their existence. Sorry, folks, it doesn't work.

3) Alignment of Earth and Sun with the "black monster" at the galactic center: This idea involves the fact that at the heart of the Milky Way -- and all other large spiral galaxies -- there lies a supermassive black hole millions of times more massive than our Sun, and that on December 21, 2012, the Sun and Earth will "align" with it. I'm not sure just how people are defining that "alignment," but if, as is usually the case, it means all three entities -- black hole, Earth, and Sun -- are on the same line, this ends up in the So What? category. Why? Because, since that black hole is at the center of mass/rotation of the Milky Way, everything else in the Milky Way revolves around that black hole every so many hundreds of millions of years. And that means that any planet of any star in the Milky Way or other galaxy which, like Earth, orbits its star in a plane parallel to the general plane of its host galaxy, is aligned with its star and the black hole at the heart of its host galaxy twice in every single one of its years. On those occasions, either it's between its star and the black hole on the line to which all three belong, or its star is between it and that black hole on the line to which all three belong. For example, as seen from Earth -- and thus from the Sun, since both are 25,000 miles from the center of the Milky Way, their orbital displacements negligible at that distance -- the galactic center, and thus the supermassive black hole at that center, is currently apparently located at 26 degrees 58' of the astrological sign Sagittarius (not quite 270 hours right ascension; this puts the galactic center somewhere back very early in the constellation of Sagittarius or late in the constellation of Scorpio -- the constellations are zones in the sky as defined by astronomers, whereas the tropical signs are twelve divisions of equal size along the celestial equator, as measured from the point in the sky occupied by the Sun at the first moment of Spring each year). So every year, on the 18th of December and 18th of June, the Sun, Earth, and the black hole at the heart of the Milky Way all lie on the same line -- hardly a once-in-a-million-year event! Furthermore, these twice-yearly alignments take place a few days before the Winter and Summer Solstices, whereas the "alignment" prophesied as happening in 2012 will supposedly take place on December 21 of that year, right on the Winter Solstice. So this one doesn't work, either.

Doubtless there are other questionable "prophecies" centering on the year 2012 which, upon examination and rigorous analysis, will be found not to hold water. This is not a matter of religious faith or lack thereof, of moral turpitude or virtue, but rather has to do with basic mechanics, celestial and mundane. Somebody didn't check their facts -- or never took basic physics, or has never driven a car, or maybe had had a few too many when he dreamed up his "prophecies" . . .