Earth's magnetic field protects us from solar radiation, as shown in this image (an artist's conception from NASA). Is it possible that this protective shield might disappear on December 21, 2012?
So far, we’ve debunked four end-of-the-world claims in our 2012 blog series (see them all here). But those who are predicting a 2012 doomsday seem to have taken a “more is more” approach in terms of their ideas about just what will bring about an apocalypse on December 21, 2012 – one website lists 22 possible causes! One pervasive claim on 2012 sites is the idea that Earth will undergo a magnetic pole reversal on 12/21/2012, leaving us completely unprotected from fatal levels of solar radiation.
First, let’s examine the facts behind this claim:
The Earth’s magnetic field has been declining in strength over the past century or so.
Earth’s magnetic field does protect us from solar radiation.
Unfortunately for the 2012 crowd, that is where the facts end. While Earth’s magnetic field strength has been declining recently, it is still well above average. A graph of field strength over time shows many fluctuations – the current decline is nothing unique. While there’s no way to prove that we aren’t heading for a reversal, there is also no definitive proof that we are.
Secondly, the protection from solar radiation afforded by our magnetic field would not disappear during a reversal. While the magnetic field strength does decrease during this process, it does not fall to zero – and even a weak field can stop many solar rays. Those that do get through a weakened magnetic field would then have to deal with our atmosphere, which is as effective at stopping solar radiation as a 13-foot-thick wall of concrete! The greatest risk during a reversal would be to satellites and astronauts orbiting the Earth at high elevations, where our atmosphere is too thin to provide much protection. If previous magnetic reversals coincided with damaging levels of solar radiation here at ground level, we would see evidence of it in the fossil record – and we simply don’t.
If these arguments haven’t convinced you, then here’s one more: magnetic reversals take thousands of years to complete, not a single day! So rest easy – and don’t be afraid to step into the sun on 12/21/2012.
To find out more about the 2012 claims, plan to attend our Science 360 show “The Truth Behind 2012” when it opens on February 6.
Casey Rawson is the Science Content Developer for Science 360. Her favorite 2012 possibility is #21; the phrase "catastrophic pinball machine" conjures up some great images.