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So I was deciding on ways to end my world in a futuristic scenario, and I had an idea. As we all know, Earth has two poles, and these poles are moving constantly (Magnetic Poles are different from actual Poles). The recent average movement is about 10KM a year. In the past the poles have completely reversed, as in, the North Pole became the South Pole.

This is all because of how the molten core of our planet fluctuates and moves. The outer liquid iron core is constantly moving around a solid inner iron core creating a magnetic field that spans thousands of kilometres into space. This magnetic field (Magnetosphere) protects our upper atmosphere and Ozone from being blown away by charged particles that emanate from the sun. Magnetosphere

Astronomers hypothesised that the weakening of Mars' magnetosphere is the reason its atmosphere almost entirely blew away.

Whilst our core is cooling (over billions of years) I wondered if it might create multiple poles, which would lower the extent our magnetosphere reaches and create more holes where the magnetosphere springs from, severely crippling our protection against solar winds perhaps to the point where it blows away our atmosphere.

Anyways, what I'm asking is, could there be more than just two poles?

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  • $\begingroup$ This is an eye opener for me. Cool. I never knew that a planet magnetic poles can be more than two. I had always thought analogical like normal magnet poles. Thank you guys. $\endgroup$ – Hariz Rizki Jan 21 '17 at 14:38
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Absolutely.

It is believed that in the past the earth had multiple chaotically spread poles and that this only changed recently around 650 million years ago when the core became less turbulent.

Our planet's dynamo is incredibly complex, so it is entirely possible that it might revert to that less orderly state, where many poles will onces again start appearing and disappearing for millions (or billions) of years.

Even more plausibly however, our poles also (north and south) periodically switch places in an event known as geomagnetic reversal, during which many poles temporarily emerge, this is even quite likely to happen within our lifetime as the last one was 780,000 years ago, yet 450,000 years is the average duration between each switch.

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Yes, during a geomagnetic reversal (which lasts from about 1000 to 10000 years, but sometimes it's much shorter) Earth magnetic field weakens and many local poles can appear.

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Yes, for a number of reasons, and it's somewhat realistic

@AngelPray and @RandovanGarabik are absolutely correct, geomagnetic reversals may weaken the magnetic field and cause multiple poles. While the shortest reversals usually take 1,000 years, you could handwave a mechanism or catastrophe to speed up the process - or have it jumpstart, etc.

In addition, other planets we have observed have very complex magnetospheres; it's reasonable to conceive of something as simple as a pole reversal here at home.

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  • $\begingroup$ What planets have multiple magnetic poles? Nearest example I can find is Uranus, but it's still a single pair of poles, but inclined at 60° from its axis of rotation. $\endgroup$ – Schwern Jan 21 '17 at 0:01
  • $\begingroup$ @Schwern I had a really good source on that and I'm still trying to find it again ... although until that happens I guess it's best to edit my answer $\endgroup$ – Zxyrra Jan 21 '17 at 7:53

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