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Pole Shift

  1. Aug 16, 2004 #1

    Mk

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    I need to know all the bad things that will happen if and when the earth's geomagnetic poles will shift. Also, about every 11 years when the sun's poles change what happens to the sun?
     
  2. jcsd
  3. Aug 16, 2004 #2

    Mk

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    also, if there was no magnetic field on the earth, how many feet of concrete or lead would you need to sheild electronics, any type you know
     
  4. Aug 16, 2004 #3
    Well, you have to retune all the TV and computer screens for instance. Or use them upside down. :biggrin:
     
  5. Aug 16, 2004 #4
    If there wouldn't be a magnetic field we'd probably be all dead.
    The earths magnetic field shields not only electronics from radiation, but also us.
     
  6. Aug 16, 2004 #5
    The earth's magnetic field shields us mainly from plasma (mainly charged particles) coming from the sun during solar flares by deflecting them. When such particles get through the atmosphere, you get what is commonly known as an aurora. This looks like some curtain of light (http://www.crh.noaa.gov/grb/images/aurora.jpg)

    I am not really sure about the other effects that a reversal in the earth's magnetic field would do but animals that use the earth's field as a means to navigate would end up in confusion. And hikers, boy-scouts would get lost because their compasses would point the wrong way. But planes and helicopters will not be affected coz I think they use gyroscopes for navigating. (http://science.howstuffworks.com/gyroscope3.htm)

    Also, I believe that power grids could be brought down.

    A really dramatic version of the loss of the earth's magnetic field is what the film 'The Core' is about. But the physics in this movie is really bad.
    http://www.intuitor.com/moviephysics/core.html
     
    Last edited: Aug 16, 2004
  7. Aug 17, 2004 #6

    Mk

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    I thought I'd get lots of stuff... well so far what I do know is that it will have affect on animals that use magnetic stuff in their brain to navigate, like birds, they would die off... that'd be bad, becuase they'd migrate south...

    The plasma from the sun yeah... I got all about that except how much lead or concrete you'd need to sheild any type of electronic.

    We'd know about the pole flip ahed of time, because the current field would decrease to 20% of what it is now.
     
  8. Aug 17, 2004 #7
    Well, the Earth magnetic field collapses globally about every 50,000 to 100,000 years for a few thousand years. Then it recovers again. This is called an Paleo Magnetic Excursion. Sometimes it appears that the magnetic field collapses locally. The last local event was possibly the Mono Lake excursion, 26,000 years ago, the last global event was the Lachamps excursion of 40,000 years ago. Before that we had the Blake excursion, 100,000 years ago. So we are not due yet, if any predictions can be made at all.

    The last magnetic pole reversal was the flip from the Matuyama chron the present Brunhes chron 780,000 years ago. (obviously a chron is the era between pole reversals). The last 50 million years ago the chrons average about half a million years, so if one can say anything the next pole flip appears to be late.

    There is no evidence for extinction upheaval related to paleo magnetic behavior whatsoever. So changes are that the environment won't notice a lot. One could image that a magnetic flip is slow enough for indiviuals to reprogram their magnetic registration devises if they exist at all.
     
  9. Aug 17, 2004 #8
    I am not completely sure about this but assuming that the effects of a pole flip leads to only plasma radiation and change in the magnetic field direction, I very much doubt that electronics would need some form of shielding.

    I would think that the plasma radiation would be absorbed by the atmosphere before it reaches ground level. And in case it doesn't, since the radiation is made up of charged particles, you could for starters have your electronics enclosed in a metal case that is grounded to earth. Now, I don't now about how deep plasma ions penetrate, but depending on their penetration depth, you might need a denser material to stop it.

    As for the magnetic field flip itself, I don't see why it should affect electronic devices. If it was to affect electronics, then rotating any electronic device we currently use about the vertical axis by 180° would lead to a malfunction! This would mean that if I face the window instead of facing the wall when using my computer, it would not work anymore, :surprise: which is totally untrue. So, I would say that the change in direction of the field will not have a direct impact on electronics.
     
    Last edited: Aug 17, 2004
  10. Aug 17, 2004 #9
    hmm, i thought the magnetic field actualy shielded us against all sorts of cosmic radiation.
    Guess someone gave me some bad info once. :grumpy:
     
  11. Aug 17, 2004 #10

    russ_watters

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    It doesn't. Its nowhere near strong enough.

    When it collapses, it'll allow more solar plasma into the atmosphere, make prettier aurora and maybe allow solar flares to cause more damage to satellites, but that's about it. Its not going to kill anyone.
     
  12. Aug 17, 2004 #11
    I wasn't kidding. Just turn your TV set upside down. Now the correction for the Earth magnetic field, affecting the electron beam is pointing the wrong way.
     
  13. Aug 17, 2004 #12
    Turning your TV set upside down does not mimic the magnetic pole flip. Turning your TV round 180 degrees does!
     
  14. Aug 17, 2004 #13
    The reason your TV might go funny if you turn it upside down would probably be due to gravity more than the earth's magnetic field.
     
  15. Aug 17, 2004 #14
    The only place where turning your TV upside down would possibly mimic the magnetic field flip is at the poles. But even that would be assuming that the gravitational effects do not affect your experiment. :smile:
     
  16. Aug 19, 2004 #15
    I read an article recently describing the process of a magnetic field reversal. Summarizing, what happens is that the magnetic field locally collapses in one or more parts of the world, the overall magnetic field then becomes progressively disorganized, multiple magnetic poles appear locally (with a much weaker overall field), and eventually the orientation of one of the local anomalies becomes dominant and the earth's overall field recovers, pointing in this new (perhaps the same as the old) direction. There was also a decent amount of information about the convection currents in the outer core, but I can't remember the details well enough to post about them.

    Now, as for whether the earth's field is in the beginning stages of a reversal, that's still up in the air. However, a magnetic anomaly in the south atlantic has become much more prominent with time, and is to the point where astronauts in low earth orbit have to take precautions during active storming periods. The earths' overall field has been declining at a fairly steady rate for most of recorded history, though I forget the way the field was measured.
     
  17. Aug 19, 2004 #16

    Evo

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    Here is a great link. Click on the "Program Transcript" on the right under resources for the complete dialogue. I think it will put your mind at ease. It's worth the read.

    http://www.pbs.org/wgbh/nova/magnetic/
     
  18. Aug 20, 2004 #17

    Mk

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    Thanks, all. :smile:
     
  19. Aug 20, 2004 #18

    Nereid

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    Only one aspect which the Nova program may not have addressed sufficiently - would there be widespread electrical grid failures if the magnetic field reversed? A: if nothing were done to today's grids, yes. However, we now know quite well what you have to do to make a grid robust to geomagnetic storms, so the only reason future grids would fail (when the Earth's magnetic field weakens greatly) would be sheer incompetence (or short-sighted, near-term profit driven stupidity) on the part of the grid owners and national regulators.
     
  20. Aug 21, 2004 #19

    Evo

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    Nereid, excellent point. I wonder if this is something that is being considered right now. We have enough forewarning to prepare for it.
     
  21. Aug 22, 2004 #20
    Well, the question of course is if technical solutions can defeat physical laws. It's not the same as the Y2K bug.

    But the pole shift don't happen overnight, the last one is pretty well documented.
    http://staff.aist.go.jp/hirokuni-oda/Odaetal2000GJI.pdf
    http://staff.aist.go.jp/toshi-yamazaki/publication/EPS0406.pdf

    The Brunhes Matuyama flip seem to have been redated from 780,000 to 789,000 years ago. It lasted perhaps up to 11,000 years and was characterized by numerous violent pole movements at random over the globe. If your electronical devices are sensitive to the Earth magnetic field, then there may be hundreds of years left to think about countering that flip, if at all.
     
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