Earth's Magnetic Field Reverses

Thread Starter

GopherT

Joined Nov 23, 2012
8,009
Every few years I hear a story that reminds me of something I learned in a Geology class a very long time ago. I don't know if it is widely known but every time I bring it up it tends to surprise people. I am still looking for an explaination.

The earth's magnetic field reverses on occasion (100k to millions of years). It seems to flip over a very short period of time. The direction can be monitored by historical rock formations (sea bed).

When I first heard about this, I thought the Geologist/professor had some type of misunderstanding of the topic - I couldn't be it was possible. Then, after confirming it, I thought it would be explained within a few years because scientific knowledge was growing so quickly. Well, here we are more than 30 years later and still no answer.

Does anyone have a theory to explain what causes the magnetic field reversal?

Read more at: http://en.wikipedia.org/wiki/Earth's_magnetic_field#Magnetic_field_reversals
 
Last edited:

#12

Joined Nov 30, 2010
18,224
Theory: It's true.

First year physics classes measure the magnetic field of the Earth. I believe that doctorate level geologists can do as well, even if they have to measure rocks to do it.
 

Thread Starter

GopherT

Joined Nov 23, 2012
8,009
I believe it is true and does happen.

The theories I am looking for should explain the cause of the reversal.
 

bountyhunter

Joined Sep 7, 2009
2,512
Every few years I hear a story that reminds me of something I learned in a Geology class a very long time ago. I don't know if it is widely known but every time I bring it up it tends to surprise people. I am still looking for an explaination.

The earth's magnetic field reverses on occasion (100k to millions of years). It seems to flip over a very short period of time. The direction can be monitored by historical rock formations (sea bed).

When I first heard about this, I thought the Geologist/professor had some type of misunderstanding of the topic - I couldn't be it was possible. Then, after confirming it, I thought it would be explained within a few years because scientific knowledge was growing so quickly. Well, here we are more than 30 years later and still no answer.

Does anyone have a theory to explain what causes the magnetic field reversal?

Read more at: http://en.wikipedia.org/wiki/Earth's_magnetic_field#Magnetic_field_reversals
It does reverse, I believe there are at least eight documented in rock. It has to do with the rotation of the earth's internal core. Ther field weakens as it approaches a reversal, and it starts by having reversals in small areas that eventually spread to the whole thing.


Earth's magnetic field is generated by the roiling of its outer liquid core. Research suggests that at times this outer core can behave as many magnets instead of one. These magnets can, in principle, cancel each other out, causing the magnetic field overall to weaken or flip.
http://news.discovery.com/earth/wea...rth-magnetic-field-poles-flip-fast-121024.htm
 

tracecom

Joined Apr 16, 2010
3,944
It does reverse, I believe there are at least eight documented in rock. It has to do with the rotation of the earth's internal core. Ther field weakens as it approaches a reversal, and it starts by having reversals in small areas that eventually spread to the whole thing.
Dang. I just bought a new compass.
 

Kermit2

Joined Feb 5, 2010
4,162
Invest in some good sunscreen lotion, say SPF 1,000,000. Our magnetic field provides protection from solar particle radiation by directing its travel towards our magnetic polar regions. Without this magnetic field the high speed particle radiation will impact molecules in the atmosphere directly above the sun facing side of the planet and everything below will get showered with secondary ray and particle radiation scatter.

Lead roofing anyone? :)
 

Kermit2

Joined Feb 5, 2010
4,162
Now that I consider the radiation aspect of polar reversals, it may be one of the reasons for the large diversity and rapid evolution of plant and animal species on this planet. Periodic intervals of intense radiation do increase mutation rates in all living organisms. An extremely large X class solar flare that makes a direct hit during such an unprotected interval might even trigger extinction level events.
 

Bob T.

Joined Oct 22, 2012
35
It does happen, but don't worry it happens every 1 millions years or something similar to that, but i know that it happened from about 50,000 years ago so the probability is low for it to happen.
 

bountyhunter

Joined Sep 7, 2009
2,512
It does happen, but don't worry it happens every 1 millions years or something similar to that, but i know that it happened from about 50,000 years ago so the probability is low for it to happen.
It's actually overdue.

As lava cools and solidifies, it preserves the direction of the Earth’s magnetic field so looking at the rock that has formed over time gives us an idea of what has happened to the magnetic poles in the past. These studies show that the poles switch ends every half million years or so – and that we’re due for another switch in the next few thousand years.
http://www.physics.org/facts/frog-magnetic-field.asp
 
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