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Tue Aug 21, 2018, 04:53 AM

Earth's magnetic poles can flip faster than first thought

https://www.dw.com/en/earths-magnetic-poles-can-flip-faster-than-first-thought/a-45151066

Earth's magnetic poles can flip faster than first thought

Date 21.08.2018
Author David Martin

We might think that a compass will always point north, but what if the earth's magnetic poles actually flipped around? Such a bizarre jump has happened in the past and, according to geophysicists, could happen again sooner and faster than first thought.

Liquid metal churning out of the Earth's core gives the planet its magnetic field. But when this liquid flows in a different direction, it can have a major bearing on our magnetic field.

On Tuesday, researchers from China published a study finding that this reverse in the planet's magnetic poles can also occur much faster than initially thought. While geophysicists previously believed that such a phenomenon could only occur over sever hundred years, new evidence suggests that the last geomagnetic switch, back at the beginning of the last ice age, took just 144 years around 30 times faster than previously thought possible. Researchers were able to able deduce these faster fluctuations in the Earth's poles by analyzing stalagmites in limestone caves, several of which were still magnetized and whose age could easily be determined.

The researchers said they had several reasons to believe that another polar flip could happen soon. First, the Earth's magnetic field is roughly 10 percent weaker compared to when records first began 175 years ago, meaning the poles are more prone to shift.

Further, the magnetic poles are moving increasingly quickly. The northern pole currently sits under the arctic ice to the north of Canada. However, every year it moves some 50 kilometers (31 miles) towards Siberia.

Their final argument: A reversal in the Earth's magnetic field is long overdue. On average it occurs every 200,000 to 300,000 years, and the last such incident was around 780,000 years ago.
(snip)

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Reply Earth's magnetic poles can flip faster than first thought (Original post)
nitpicker Aug 2018 OP
3Hotdogs Aug 2018 #1
marble falls Aug 2018 #3
no_hypocrisy Aug 2018 #2
marble falls Aug 2018 #4
Igel Aug 2018 #5
muriel_volestrangler Aug 2018 #6

Response to nitpicker (Original post)

Tue Aug 21, 2018, 06:22 AM

1. How am I gonna find my way to Moe's Tavern?

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Response to 3Hotdogs (Reply #1)

Tue Aug 21, 2018, 07:50 AM

3. Take out your compass and walk backwards. Sheeesh. Do I gotta 'splain ever'ting?

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Response to nitpicker (Original post)

Tue Aug 21, 2018, 06:35 AM

2. Excuse the ignorance, but does that mean that the Southern Hemisphere would

become the Northern Hemisphere (and vice versa)?

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Response to no_hypocrisy (Reply #2)

Tue Aug 21, 2018, 07:51 AM

4. Its the only way the South will rise again. Unless they plant yeast instead of cotton.

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Response to no_hypocrisy (Reply #2)

Tue Aug 21, 2018, 08:57 PM

5. No.

There's the map-based north pole, then there's the magnetic north pole.

We already have it wrong. The north pole of the magnet that is a compass points towards the geographic, map north pole. Since opposites attract, that magnetic north pole of the compass points to a magnetic south pole.

So the Earth's North Pole that's moving towards Siberia is actually a magnetic south pole.

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Response to nitpicker (Original post)

Sun Aug 26, 2018, 10:28 AM

6. Slightly out of date - it's moved so fast it's now north of Siberia, not Canada



It's pretty much at 180W now, Siberia starts at 170W.

I never realised there's difference between the 'magnetic pole' and the 'geomagnetic pole'. The former is the one that'd been moving fast, and is the point where a compass will point straight down into the earth. The latter is the point where the best model of the earth as a simple dipole magnet would put it; so the north and south geomagnetic poles are always directly opposite each other. The magnetic poles, however, aren't; the south one has been moving away from the south geographic pole while the north magnetic pole was moving towards the north geographic pole.

https://en.wikipedia.org/wiki/North_Magnetic_Pole#North_Geomagnetic_Pole

http://wdc.kugi.kyoto-u.ac.jp/poles/polesexp.html

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