Is the world likely to end regarding astronomical changes in 2012?

Question posed by Magenius

There's a doomsday 'theory' doing the rounds on the internet at the moment (and has been for some time) that predicts the end of the world in December 2012. As I understand it, this latest in a long history of doomsday predictions (all proven false by the very fact that we're still here), has sprung forth from the fact that a calendar system used by a number of ancient Mesoamerican peoples including the Maya comes to an end on this date.

My first issue with this particular armageddon prediction doesn't have much to do with astronomy, so I won't spend much time on it, just to say that the Mayan calendar system in question didn't have an end date as such, rather that it ran in cycles called 'Baktun', and at the end of thirteen of these cycles (a total of 5125.26 years*), rather than the world vanishing down a cosmic plughole, the calendar simply resets, much like the odometer in a car**.


The (alleged) astronomical issue
Apparently the mechanism by which we are to be destroyed (or transcended to a higher plane, as some folks would have us believe) is a supposed 'alignment' that will occur on the very date that the Mayan calendar is set to expire. Celestial alignments of any sort seem to hold a particular fascination with the kind of people who peddle doomsday claptrap to the masses - think back to the latter years of the last century, and you may remember similar stories of impending doom due to a planetary alignment. This obsession with ascribing meaning or purpose (benign or otherwise) to alignments in the sky may well have something to do with the human race's continuing obsession with astrology which is, after all, based in superstition and mythology, rather than science and fact. That's not to say that it can't be fun when played with appropriately, but using it to spread fear and misinformation is something that I can't help but frown upon.

Anyway, the alignment is said to be between the Earth, Sun and galactic centre. A number of people are assuring us that this means that Earth/solar system will be at its closest ever point to the galactic centre, meaning that... well, I've heard all sorts here, from previously undetected black holes or brown dwarf stars raining down on us, to us passing through a photon stream, to gravitational effects due to the alignment causing increased solar activity and frying us all.

My first comment is that I fail to see how an Earth - Sun - galactic centre alignment can cause any of these events. I have seen no '2012 phenomenon' proponent give any real evidence for any of the events that he or she has decided are going to happen. In fact, many of the accounts that I have read start off plausibly enough, with some decent background science talking about the way our solar system orbits the supermassive object at the centre of our galaxy, as well as some pretty sane comments about the Mayan calendar system and its history. But at some point, usually around the mention of The Alignment, the text invariably goes one of two ways: either it starts spouting bad, misunderstood or downright fabricated science, or it descends into outright hysteria.

But back to the science: I have four further comments to make, with the rather charitable assumption that celestial alignments can be the cause of things going horribly wrong for the human race***:

1. There will be a vague alignment of the Sun with 'the great rift'**** as seen from our vantage point on Earth. There is, however, no evidence that I have come across so far that the Sun will actually align perfectly with the galactic centre. If there is such an alignment, due to the Earth's movement around the Sun, it will be momentary. Another way of looking at it: the bulge at the galactic centre is so large, that the Earth-Sun-galactic centre will happen once a year starting in 1980, and ending in 2016. We haven't yet been ripped apart, so why should it happen in 2012?
2. The Earth/ solar system will be no closer to the galactic centre in 2012 than it has been in the last few thousand years, or will be in the next few thousand. This part of the story is tripe from the start.
3. This 'alignment' is certainly a rare one - it happens once every 26 thousand years or so. But that means that it has happened before, and is there any evidence for massive loss of life on Earth at the time? No. In fact, the most recent mass-extinction event was around 65 million years ago when the dinosaurs became extinct, and that, most astronomers currently believe, was caused by a big rock from space, not a galactic alignment.
4. A number of 2012ists go one step further and state that the solar system follows a 'wavy' path around the galactic centre, and therefore crosses the 'galactic plane' every so often. This is true. They also state that this will happen on December 21 2012, and that this will cause the galactic alignment to be even more un-groovy for us. This is false. This is, in fact, utter tosh as we are currently some considerable distance above the galactic plane, and moving further away. We will not cross the galactic plane again for at least another 30 million years.

So is the world likely to end in 2012?

No. No more than in any other year. Please disregard any of the 2012 rubbish you may come across in your travels around the internet, and if a friend or family member sends you anything about it, please do the right thing and let them know it's all a big pile of stupid.

Have a question about this topic? Comment below! Got an astronomy related question of your own? Ask it here.




* They were an optimistic lot.
** When (if) you reach the 'end' of your odometer's ability to count, your car doesn't puff out of existence or (necessarily) encounter some great cataclysm and/or explode. The counter just goes back to zero.
*** I don't actually believe this for a moment, but it simplifies things a bit.
**** The dark band through the centre of the Milky Way caused by interstellar dust blocking light from further afield.