Sky Guy: Will the world end on December 21? Look at the science

Well, at least it will soon be over.

Not the actual end of the world, mind you, but the persistent speculation and fear about the world ending on December 21, 2012. Although this prophecy actually goes back at least three decades, the Internet and other social medias have been increasingly accelerating and perpetuating this idea for the past 10 years or so.

Some TV stations have even been airing "documentaries" about the upcoming end of the world. With menacing music, special effects and selective facts, so-called "experts" try to sell the viewer on their conclusions.

And there are books.A lot of books.Books that are foretelling the end of the world; books invoking panic about the end of the world; books about how to survive the end of the world; and psycho-babble books about how to deal with the stress of the end of the world.

I am surprised that no one has yet published, "The End of The World for Dummies!"

Hollywood even jumped on the bandwagon with the disaster movie "2012," released in 2009.

And, of course, charlatans have been giving speeches and interviews about how the world will end in December 2012.

Documentaries, books, movies, interviews, speeches - wow! It would seem that the end of the world is a profitable business indeed. It always has been. And that is why there are, and forever will be, those who will create, manipulate, and enable alarm about Doomsday: Dollars.

So here we are just a few days away from the climax of the "Dec. 21, 2012 apocalypse" fad, and some people are beginning to worry.

And, all the while, scientists are shaking their heads in disbelief, wondering how people could be so gullible.

This date, Dec. 21, 2012, has become the focus of so much doom and gloom because it is a convergence of many unrelated events that independently would normally be overlooked or ignored. But together, pretenders have used them to mastermind and create an elaborate labyrinth of misrepresentation.

At the heart of this fairy tale is something that most people have never even thought about or even heard of until recently: the Mayan calendar.

This is not the first time a calendar has generated anxiety. Why, just recently our own Western Gregorian calendar produced a scare. Who remembers when religion, astrology, and even Nostradamus were used to predict that the world would end, or become misaligned, or be besieged by catastrophes, all because of a change in the cycle of a calendar?

Very good; put your hands down. That particular round of nonsense was coined "Y2K." And in case you haven't paid attention since Dec.31, 1999, the world is still here.

And now it is all happening again. It is time for your ol' buddy Tom to come to the rescue and do some rumor control. Let's deal with each concern separately.

THE MAYAN CALENDAR

So what's all the hubbub about?

On Dec. 21 (or 23), which also happens to be the winter solstice, the Mayan calendar, adopted from the Olmec civilization, will read all zeros: 13.0.0.0.0. This marks the end of Baktun 13, one of the Mayan time cycles analogous to our century increments. One Baktun is about 394 years.

Why December 21 or 23? As with any dating and cataloging of historical records, there must be an agreement of a zero date, or origin, of calendars. In this case, there must be alignment between the Mayan calendar and our Gregorian calendar, the currently accepted international civil calendar. Most scholars agree as to the Mayan zero date and, therefore, agree that Baktun 13 ends on December 21.

However, there are a handful who subscribe to a different Mayan zero date and thus claim that Baktun 13 ends on December 23.

Although it has been studied extensively by archeologists, anthropologists and historians, there is nothing special about the Mayan calendar or this particular Baktun cycle. At least no more special or magical than any other time-keeping method used by cultures past or present throughout the world.

The Mayans simply believed that another cycle would begin where the previous one ended. Consider: Most of our calendars end on December 31.

That's all there is to it.

At no time did the Mayans predict that the world would end at the completion of one of their cycles. In fact, some Mayan long-count texts refer to dates many Baktuns past 13, going as far ahead as the year 4772 by our calendar.

Indeed, the only significance to the ending of a Baktun cycle is that the Mayans would celebrate period endings. We do the same thing every New Year's Eve.

It really wasn't until the 1970s when New Age authors started to write about the Mayan Baktun cycle did somw people start to become concerned, roused by authors' claims that it would mark the end of the world.

One author in particular, who I will not promote by acknowledging, fueled this growing hysteria by making a fuss over the fact that Dec. 21, 2012, is also the winter solstice and that the sun, when viewed from Earth, would be near the galactic center.

(The operative word here is "near;" for the sun never eclipses the galaxy's true center from our terrestrial point of view and the closest winter solstice alignment with the galactic center isn't for another 200 years. More on this later.)

Since then, there have been many broad and creative interpretations of the Mayan calendar, celestial alignments and astrological meanings about how Dec. 21, 2012, is going to be devastating. None of these arguments are based on observations, facts, experiments, or - let's just say it - reality.

PLANETARY ALIGNMENT

There is no special arrangement of the planets this month. In fact, they are spread out in a rather unremarkable way, even more so when considered in three-dimensions.

'Nuff said.

NIBIRU

Another assertion presented by advocates of the 2012 end-of-the-world scare is the alleged existence of a mysterious planet adrift in our solar system. This world, called Nibiru, is claimed to be heading straight for Earth, either on a collision course or a near flyby.

This planet was supposedly first discovered by the Sumerians, an ancient civilization. Some stories of Nibiru also include - what else? - aliens, called the Anunnaki, who purportedly once visited Earth.

Oh, but there is more. Self-proclaimed Nibiru expert Nancy Lieder, who claims to be in communication with aliens from Zeta Reticuli via an implant in her brain (really), initially calculated the Nibiru cataclysm to occur in May 2003. When that didn't happen, she readjusted her prediction to link it with the Mayan calendar.

In actuality, the Sumerians never developed advanced astronomy or even understood simple celestial mechanics. Claims to the contrary are manufactured by artists and speakers who want to sell their wares. It was Lieder who originated the Nibiru encounter.

Of course, there is no such world as Nibiru, and the many discoveries of dwarf planets in the Kuiper Belt beyond Neptune do not support the existence of some secret planet that would enter the inner solar system.

If a planet or other massive body were heading toward the Earth, its gravitational influence would have been observed, especially on the outer planets. In addition, thousands of professional and amateur astronomers from all over the world would already know about it.

Further, it would now be visible to the naked eye; anyone looking to the heavens would be able to see it. No one has.

We must also note that such a direct trajectory would violate the physics of orbital dynamics that govern the motions of celestial bodies.

But enter the conspiracists who claim that "they" (usually the government, NASA, or the United Nations) are covering it all up and silencing those who know "The Truth."

Let's be realistic: The existence of a nearby, invisible, undetected planet is a ridiculous claim.

GALACTIC CENTER ALIGNMENT

The alignment and intersection of certain celestial orbs and circles happening at the same time as the Mayan Baktun 13 ends is often offered as verification by doomsayers. It does sound ominous and rare. It is also misrepresented, playing on the public's general misunderstanding of astronomy.

Let's sort through it. As I often like to do, I'll begin by defining some terms.

The ecliptic is a circle on the celestial sphere (sky) that traces the apparent path of the sun throughout a year. Of course, it actually represents the orbit of Earth around the sun, but for our discussion we are interested in only geocentric perspectives (as were our ancestors).

Second, we'll consider the galactic equator. The Milky Way galaxy, as with most galaxies, is planar, or situated on a plane, but it does have some thickness. There is an imaginary line that divides this plane into a "top" and a "bottom." This is the central plane of our galaxy, called the galactic equator and, in galactic coordinates it is zero degrees.

This is not unlike how the equator on Earth, with latitude of zero degrees, divides the globe into a Northern ("top") and Southern ("bottom") Hemispheres.

We must realize that the ecliptic, as a great circle, is going to intersect with the galactic equator as seen from Earth. It has to, for it encircles Earth on the celestial sphere. This is basic geometry and has no special meaning.

What is interesting, and even a little counter-intuitive, is that the intersection of these two planes is about 60 degrees. That is, Earth and the other planets of our solar system, do not orbit the sun parallel to the plane of the galaxy or even the sun's orbit around it.

Finally, our third term: The winter solstice is that point on the ecliptic where the sun is at its lowest point in the sky in the Northern Hemisphere. This event occurs on or near December 21 of every year and marks the first day of winter.

Now, let's bring all this together.

The intersection of the ecliptic with the galactic equator is a mere mathematical point in space, lacking any dimension. However, the sun is a physical object and therefore has an angular diameter, approximately 0.5 degree. You have observed this: the sun is a disk in the sky.

On December 21, which is the winter solstice this year, the intersection of the ecliptic and the galactic equator will be eclipsed by the disk of the sun as seen from Earth. This is not a rare occurrence, and certainly not one that marks or causes the end of the world.

All this means is that the sun, as a two-dimensional disk from our vantage point, will be overlapping a geometric point in space as seen from Earth. (I keep emphasizing "as seen from Earth" because none of this exists from the vantage points of other planets or moons in the solar system. They have their own alignment geometries.)

Earth wobbles as it rotates on its axis, a phenomenon called precession. This is a 26,000-year cycle that also has no grand significance; it is the same physical principle that causes a spinning top to wobble. But as a result of this precession, the winter and summer solstices, and the vernal and autumnal equinoxes, all shift by about a degree every 71.5 years.

Therefore, since the sun is about 0.5 degree wide, it takes the winter solstice sun 36 years to precess through the galactic equator.

Are you ready for a surprise? The winter solstice sun started to eclipse the galactic equator in 1980. Every year since then, the disk of the sun was in alignment with the galactic equator on December 21.

Every year.

Further, the closest center alignment of the disk of the winter solstice sun with the ecliptic/galactic equator intersection was in 1998. In case you haven't noticed, the world did not come to an end because of this.

The disk of the winter solstice sun will not leave the ecliptic/galactic equator intersection point until 2016.

So, given that the solar system is nearly 5 billion years old, that the sun orbits the Milky Way once every 250 million years, that Earth has been undergoing one precession cycle every 26,000 years, that Earth orbits the sun once a year, and that the other planets also orbit the sun, it becomes clear that there have been many alignments of various things. And there will continue to be in the future.

These arrangements are simply the result of a dynamic universe. We shouldn't try and invent some magical astrological interpretation of them.

(Disclaimer: Before some of you start writing angry letters to the editor, yes, I am aware that the alignment of Earth, moon and the sun does cause the tides. But this is gravitational physics - it doesn't "mean" anything.)

OTHER SPACY CLAIMS

Some other concerns that have popped up over the Dec. 21, 2012, end-of-the-world scare are usually spin-offs from Nibiru or the ecliptic/galactic equator alignment.

One of these claims is that Earth will flip over or reverse its rotation because of some type of "cosmic energy." We must remember that Earth is being bombarded by energy and radiation every second of every day, both from the sun and from interstellar space.

Only a massive collision with another body (enter Nibiru) could overcome the momentum and inertia to flip the planet or change its rotation.

Others allege that Earth's magnetic field will suddenly reverse its polarity. This one is at least partially grounded in reality, but it is still pseudoscience. And it has nothing to do with any heavenly alignment or calendar date.

The polarity of Earth's magnetic field does indeed cycle. It has flipped about two dozen times in the past 5 million years, the last time being 780,000 years ago. Our magnetic field has weakened by about 30 percent during the past 2,000 years, an indication that another polarity reversal is in progress.

But these magnetic events have never caused any large-scale extinctions. Our ancestors survived several such reversals without any significant drop in population.

The flipping of Earth's magnetic polarity is not a rare or isolated occurrence and is a gradual process that takes place over hundreds of centuries. The 24-hour timeframe of December 21 is irrelevant and quite insignificant to that process.

Other random arguments have also been tossed into the mix. One links disaster with the supermassive black hole at the center of our galaxy, some 30,000 light years away and something of which the ancient Mayans would have had no concept. Another posits that there will be great solar storms that will incinerate Earth, but scientists point out the sun is behaving in its typical and usual way.

We must keep our imaginations in check.

CONCLUSION

Calendars exist as tools only. They keep track of the passing of time and are manmade constructs. Nature does not "know" what a calendar and its units are. The universe continues on, obeying physical laws, and not in any way influenced by our superstitions.

I can say from personal experience that there is always some group somewhere that thinks the world is about to end. They are usually fanatics who have uncovered some "Truth," astrologers who think the alignment of some celestial bodies are portents of doom, or just individuals who think the woolly worms look funny. These people usually receive little attention.

Worse, there are those looking to make a buck by selling books, movies and TV shows or convincing the susceptible and gullible to surrender all their positions.

None of these prophecies are ever based on scientific principles. Earth is still here. It will be for many millennia to come.

I know that stories of ancient civilizations, mysticism and the end of the world are exciting. Very "Indiana Jones-ish." But it is just fun. We must not be paranoid about nonsense.

I am disappointed when facades like this are brought into the spotlight and people believe it. Why in the 21st century - the information age - do people still buy into them? This I don't understand.

Bill Nye, the Science Guy, once said, in the face of scientific ignorance, that as an educator he feels that he has failed. Maybe some fault does lie, in part, with science teachers who, either by choice or policy, have not properly taught students the scientific method and critical thinking.

As a science educator myself, this I do understand.

But people have to take personal responsibility as well.The wealth of our knowledge is but a few keystrokes away.I will concede that it can be tedious to sort through everything, but learning in any form is never easy.

As for me, I am making plans for 2013.

December 21 will be nothing more than the shortest day of the year in the Northern Hemisphere. Let us not turn into anything more than that.

Tom Webber, the Times-Union's Sky Guy, is the director of the Bryan-Gooding Planetarium/Alexander Brest Space Theater at the Museum of Science & History. He writes a column each month in the Life section and also lends his expertise when there's something special going on, or just when he feels like it.