There are a lot of theories as to just how the world will end on 21 December 2012, from a Mystery Planet
, various ways the earth will align with different things
, to the Sun going crazy
. My personal favourite, however, is that the Earth’s poles will reverse, with total chaos resulting. As usual with all these theories, every lunatic and crackpot has their own interpretation of what exactly this means and claims that theirs is the only Truth. While researching this article, I was surprised at the sheer number of different interpretations — far too many to tackle individually. Their are common threads, however, usually real facts carefully edited and distorted to back the false claim, or copy-and-pasted from rival believers.
Every now and then, the Earth’s magnetic poles switch places. North becomes South, and South becomes North. The reversals are visible in geological records, and we can see that the field has reversed tens of thousands of times since the Earth’s creation. In addition, the magnetic field fluctuates in strength, and the alignment is variable. At the moment, for example, the Magnetic North Pole is moving from Canada to Siberia, and is accelerating – it was moving at 10km per year at the beginning of the 20th century, compared to 40km per year at the beginning of the 21st century. However, the reversals have nothing to do with the rotation of the Earth.
In addition, the reversals are not regular. The last reversal was a little under eight hundred thousand years ago. The longest gap between reversals yet found is more than fifty million years, and the shortest is only a few thousand. A graph of all geo-magnetic reversals shows a random distribution – in other words, the reversals do not follow any timetable, and are not predictable. Anybody claiming to know when the next reversal will happen, or that we are “overdue”, is not speaking the truth.
Polar reversal refers to the North and South poles switching places. Unlike the magnetic poles, the North and South poles mark the points around which the Earth rotates – the imaginary axis of rotation passes through the North and South poles. Although there is a connection between the Earth’s rotation and the Earth’s magnetic field, the location of the poles has nothing to do with the location of the magnetic poles. When a geo-magnetic reversal happens, a compass will point in another direction, but the Earth won’t suddenly flip over, or screech to a halt and rotate in the other direction and I will demonstrate why. The Earth’s surface rotates at a speed of almost 1700km/h. You can calculate this yourself: The equator is, very roughly, about 40000km long, and a day is 24 hours. Any point on the equator therefore moves 40000km in 24 hours, or 1666.66km/h. Assuming it now suddenly rotates the other way around at the same speed, that means it has to change speed by over 3000km/h. Of course, the atmosphere is free to move as it pleases, so it will take a while to catch up. Can you imagine the effects of a 3000km/h wind, over the entire surface of the planet? What about the oceans? What would happen to every single mountain, every single house and car and boulder and animal? NOTHING would survive, and this is the scenario painted by the most extreme 2012 theorists. Now, we know that geo-magnetic reversals have happens thousands of times in the past, yet we still have mountains that are hundreds of millions of years old! We still have life on earth! In other words, there is no connection between Geo-magnetic reversals and Polar reversals.
You could argue, perhaps, that the poles change place, but that the Earth continues to rotate in the same direction. You can test this theory by spinning a gyroscope (or more dramatically, a bicycle wheel) and then suddenly trying to flip it upside down. The gyroscopic forces involved are surprisingly powerful. A hand-held gyroscope will buck wildly, the bicycle wheel will tear itself from your grip and fly across the room. An entire planet? No.
Some 2012 theorists argue that the changing magnetic field interacting with the Sun’s magnetic field is what flips the earth over. But the Earth’s magnetic field simply isn’t that powerful. Look at how slowly the needle on a magnetic compass, weighing only a few grammes swings around. The Sun’s field is actually quite powerful, but the strength fades with distance – at 150 million kilometres away it’s faint enough to be undetectable. Try to imagine how powerful the force required to move trillions and trillions of tonnes of rock and magma must be, and it becomes obvious that the interacting magnetic fields have no effect at all.
Exposure to Radiation
The most important thing about the Earth’s magnetic field, from the point of life, is that it carves out a region of space known as the Magnetosphere. This region marks a boundary past which certain types of radiation are deflected onto new paths. Particles from the Sun and deep space hurtling towards Earth are scooped up by the Earth’s magnetic field and neatly steered towards one of the magnetic poles where they eventually swoop down and hit the upper atmosphere, exciting the gasses and creating the ghostly glows known as Aurora Borealis and Aurora Australis. Some of the doom-mongers suggest that, during a geo-magnetic reversal, we will lose the magnetosphere and be exposed to deadly radiation from space.
For once they got the basics right, but as usual they’ve left out some important details. First, the magnetosphere plays no part in protecting us from the most abundant forms of radiation – gamma rays, X-rays, ultra-violet light and cosmic rays. These are all absorbed by the atmosphere, ten’s of kilometres above the ground. Even those particles which move slowly enough to be deflected by the magnetosphere (which, incidentally, should not be taken lightly – they pose a very real and serious danger for astronauts outside the atmosphere, and even air-liners cruising at high altitudes are exposed to a small dose) are partially absorbed by the atmosphere.
The amount of radiation reaching the surface of the Earth would definitely increase, but not by much. More people would suffer skin cancer. We would not all die horribly from radiation poisoning.