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Post by Al Truest on Nov 20, 2003 1:58:02 GMT
MM, have you heard theories of the Earth's geomagnetic field reversing, whereby there may be from four to eight 'poles'. This reversal could last for more than 3,000 years. It would increase skin cancer exposures by a sizeable amount, but everyone would get to see "Northern Lights" at night.   |
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Post by Lori on Nov 20, 2003 22:44:19 GMT
But wouldn't the sun have died out before then? Also, what are Northern Lights?  |
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Post by Al Truest on Nov 21, 2003 4:16:50 GMT
Lori, there are no studies that suggest (that I'm aware of) the end of the sun in the next few thousand years. I was saying that the field reversal is possibly overdue, and could stay reversed for 3,000 years. The 'Northern Lights' or, 'Aurora Borealis' as it is known in the northern hemi-sphere, is a stream of plasma that follows the earth's magnetic field. When combined with gases in the ionosphere, it produces beautiful light shows in the sky. The colors range from from red, green, blue and violet. This photo taken in Finland demonstrates this phenomenon:  With 2-4 times as many magnetic poles, these could be seen around the world. |
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Post by Lori on Nov 21, 2003 8:07:23 GMT
Ahhh. But what is a field reversal? |
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Post by Al Truest on Nov 21, 2003 14:49:25 GMT
Simply stated, a field reversal would be like the North Pole would become the South Pole. However, it could be more complex than that. There are presently several anomolies in the field that are becoming larger. When these pockets join each other, they could reverse the Earth's magnetic field. There could be as many as 8 poles, not just North and South. Can anyone guess (or know) the ramifications of such an event?
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Post by madscientist on Nov 21, 2003 21:15:09 GMT
Hiya Yawl, Magnetic field reversal, yeah, heard of the poles swapping every few tens of millions of years or so, but not about several poles at the same time. Although the earths magnetic field does vary across the surface due to anomalies in the thickness and composition of the crust the magnetic field itself is created in the earths core, probably due to the motion of electrons in the liquid centre (Mmmm, Liquid Centre), another one by our friend Maxwell, and acts like a big bar magnet. I shall have to have a look around about it! northern lights, spot on. The plasma comes from the sun in the form of protons and electrons, these bing charged, interact with the magnetic field and follow the field lines to the poles which is why you get the lights there. The green colour is due to interactions with Nitrogen and red is due to interactions with Oxygen in the upper atmosphere. At times when the sun is particularly active you tend to get more aurora activity. Lori, up in Newcastle you should get quite a few good displays Look north on a clear night. For some reason the aurora tends to be more active during March and September but can occur at any time. Speak again soon all the best. MM
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Post by madscientist on Nov 25, 2003 6:52:53 GMT
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Post by Al Truest on Nov 29, 2003 18:09:02 GMT
Thanks MM! Very good intel. It does reveal that there are as many as eight poles. A temporary shift during a reversal could result in as many as six new poles for an undetermined period. The thought of that and the ramifications would be mind staggering. But reversal more than likely would be a north to south process.  |
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