I caught the end of a NOVA program last night and was facinated by it.... the subject was about the earth's magnetic pole flipping from North to South. (00) Huh?! Say What?!
Using information stored in old lava flows (contains information about the levels of magnetic energy at the time of the flow) and the abilities of a supercomputer to process complex equations over a period of years rather than centuries, it shows that the earth's magnetic field flips from North to South every 200,000 years or so. (The timing fluctuates from 10,000 to over 700,000 yrs, but the average is 200,000 years.) And we're waaaay over due for a 'flip'.
It appears this flipping process maintains the earth's magnetic energy, rather than having it "decay" as they usually do when left alone. Also, during the transition the protection against the sun's ultraviolet rays weakens... this would cause more cancers. (hmmmm.... might explain how dinasaur remains were found to have cancerous growth even though they didn't smoke cigarettes.) Who knows what else may happen. I wonder if this has anything to do with the upcoming event predicted by the spiritual guru's for 2011/2012. Could be.
There are indications that we are in the process of 'flipping' now. Here is an article about it or do a google search... you'll get many hits using "earth magnetic flip" as a search key. Or, of course, you can make up your own search keys.
(Here's a CNN article that may be a little easier to read.)