Magnetic Storm

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Science Documentary hosted by Gene Galousha and published by PBS broadcasted as part of PBS Nova series in 2003 - English narration

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Like the plot of a sci-fi B movie, something weird is happening deep underground where the constant spin of Earth's liquid metallic core generates an invisible magnetic force field that shields our planet from harmful radiation in space. Gradually, the field is growing weaker. Could we be heading for a demagnetized doomsday that will leave us defenceless against the lethal effects of solar wind and cosmic rays? "Magnetic Storm" looks into our potentially unsettling magnetic future.

Scientists studying the problem are looking everywhere from Mars, which suffered a magnetic crisis four billion years ago and has been devoid of a magnetic field, an appreciable atmosphere, and possibly life ever since, to a laboratory at the University of Maryland, where a team headed by physicist Dan Lathrop has re-created the molten iron dynamo at Earth's core by using 240 pounds of highly explosive molten sodium. The most visible signs of Earth's magnetic field are auroras, which are caused by charged particles from space interacting with the atmosphere as they flow into the north and south magnetic poles.

At the present rate, Earth's magnetic field could be gone within a few centuries, exposing the planet to the relentless blast of charged particles from space with unpredictable consequences for the atmosphere and life. Other possibilities: the field could stop weakening and begin to strengthen, or it could weaken to the point that it suddenly flips polarity-that is, compasses begin to point to the South Magnetic Pole.

Such a reversal of polarity seems to happen every 250,000 years on average, making us long overdue for another swap between the north and south magnetic poles. Scientist Gary Glatzmaier of the University of California at Santa Cruz has actually observed such reversals, as they occur in computer simulations. These virtual events show striking similarities to the current behavior of Earth's magnetic field and suggest we are about to experience another reversal, though it will take centuries to unfold. Some researchers believe we are already in the transition phase, with growing areas of magnetic anomaly-where field lines are moving the wrong way-signaling an ever weaker and chaotic state for our protective shield.

Geophysicist Rob Coe, also of the University of California at Santa Cruz, may have even found a lava record in Oregon that charts the magnetic mayhem that ensues during a period of reversal. The picture that emerges may not be up to Hollywood disaster standards, but considering that human civilization has never had to cope with such a situation before, it could be an interesting and challenging time