The Earth's magnetic field protects our planet from dangerous solar and cosmic rays, like a giant shield. As the poles switch places (or try to), that shield is weakened; scientists estimate that it could waste away to as little as a tenth of its usual force. The shield could be compromised for centuries while the poles move, allowing malevolent radiation closer to the surface of the planet for that whole time. Already, changes within the Earth have weakened the field over the South Atlantic so much that satellites exposed to the resulting radiation have experienced memory failure.That radiation isn't hitting the surface yet. But at some point, when the magnetic field has dwindled enough, it could be a different story. Daniel Baker, director of the Laboratory for Atmospheric and Space Physics at the University of Colorado, Boulder, one of the world's experts on how cosmic radiation affects the Earth, fears that parts of the planet will become uninhabitable during a reversal. The dangers: devastating streams of particles from the sun, galactic cosmic rays, and enhanced ultraviolet B rays from a radiation-damaged ozone layer, to name just a few of the invisible forces that could harm or kill living creatures.How bad could it be? Scientists have never established a link between previous pole reversals and catastrophes like mass extinctions. But the world of today is not the world of 780,000 years ago, when the poles last reversed, or even 40,000 years ago, when they tried to. Today, there are nearly 7.6 billion people on Earth, twice as many as in 1970. We have drastically changed the chemistry of the atmosphere and the ocean with our activities, impairing the life support system of the planet. Humans have built huge cities, industries and networks of roads, slicing up access to safer living spaces for many other creatures. We have pushed perhaps a third of all known species toward extinction and have imperiled the habitats of many more. Add cosmic and ultraviolet radiation to this mix, and the consequences for life on Earth could be ruinous.And the perils are not just biological. The vast cyber-electric cocoon that has become the central processing system of modern civilization is in grave danger. Solar energetic particles can rip through the sensitive miniature electronics of the growing number of satellites circling the Earth, badly damaging them. The satellite timing systems that govern electric grids would be likely to fail. The grid's transformers could be torched en masse. Because grids are so tightly coupled with each other, failure would race across the globe, causing a domino run of blackouts that could last for decades. No lights. No computers. No cellphones. Even flushing a toilet or filling a car's gas tank would be impossible. And that's just for starters.But these dangers are rarely considered by those whose job it is to protect the electronic pulse of civilization. More satellites are being put into orbit with more highly miniaturized (and therefore more vulnerable) electronics. The electrical grid becomes more interconnected every day, despite the greater risks from solar storms.No lights. No computers. No cellphones. Even flushing a toilet or filling a car's gas tank would be impossible. And that's just for starters.One of the best ways of protecting satellites and grids from space weather is to predict precisely where the most damaging force will hit. Operators could temporarily shut down a satellite or disconnect part of the grid. But progress on learning how to track damaging space weather has not kept pace with the exponential increase in technologies that could be damaged by it. And private satellite operators aren't collating and sharing information about how their electronics are withstanding space radiation, a practice that could help everyone protect their gear.We have blithely built our civilization's critical infrastructure during a time when the planet's magnetic field was relatively strong, not accounting for the field's bent for anarchy. Not only is the field turbulent and ungovernable, but, at this point, it is unpredictable. It will have its way with us, no matter what we do. Our task is to figure out how to make it hurt as little as possible
The science shows that magnetic pole reversal is - in terms of geologic time scales - a common occurrence that happens gradually over millennia. While the conditions that cause polarity reversals are not entirely predictable - the north pole's movement could subtly change direction, for instance - there is nothing in the millions of years of geologic record to suggest that any of the 2012 doomsday scenarios connected to a pole reversal should be taken seriously. A reversal might, however, be good business for magnetic compass manufacturers.
There is an island populated by stone age people who have had pretty much no contact with modern humans. It is forbidden to go there, and the one ship that did run aground suffered the fate of every soul aboard being killed by the stone age humans.
On August 2, 1981, the MV Primrose ran aground on North Sentinel Island, stranding twenty-eight sailors. The next morning, the captain of the ship broadcast urgent messages indicating that natives were on the verge of attacking the vessel with arrows and spears. After being shipwrecked for two weeks, all crew and passengers on the ship were successfully evacuated by helicopter.
In 2006, Sentinelese archers killed two fishermen who were fishing illegally for mud crabs within range of the island. Their boat's improvised anchor failed to prevent it from being carried away by currents while they were asleep. The boat drifted into the shallows of the island, where they were killed. An Indian Coast Guard helicopter that was sent to retrieve the bodies was driven off by Sentinelese warriors, who fired a volley of arrows.