- 3068 - EARTH - magnetic field flips N. to S.? - The end of the world as we know it could come in any number of ways. Some believe global cataclysm will occur when Earth's magnetic poles reverse. When north goes south, the continents will lurch in one direction or the other, triggering massive earthquakes, rapid climate change and species extinctions. We are a species too.
--------------- 3068 - EARTH - magnetic field flips N. to S.?
- The geologic record shows that hundreds of pole reversals have occurred throughout Earth's history; they happen when patches of iron atoms in Earth's liquid outer core become reverse-aligned, like tiny magnets oriented in the opposite direction from those around them.
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- When the reversed patches grow to the point that they dominate the rest of the core, Earth's overall magnetic field flips. The last reversal happened 780,000 years ago during the Stone Age, and indeed there's evidence to suggest the planet may be in the early stages of a pole reversal right now.
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- What will actually happen when north-pointing compasses make a 180-degree turn toward Antarctica? Will the continents tear themselves apart, or are we in store for much more mundane changes?
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- Earth's magnetic field takes between 1,000 and 10,000 years to reverse, and in the process, it greatly diminishes before it re-aligns. It's not a sudden flip, but a slow process, during which the field strength becomes weak, very probably the field becomes more complex and might show more than two poles for a while, and then builds up in strength and aligns in the opposite direction.
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- The scientists say it's the weak in-between phase that would be roughest on Earthlings.
A strong magnetic field helps protect Earth from blasts of radiation from the sun. Coronal mass ejections (CMEs) occasionally occur on the Sun, and sometimes hurtle directly toward Earth. "Some of the particles can be blocked by Earth's magnetic field. With a weak field, this shielding is less efficient.
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- The charged particles bombarding Earth's atmosphere during solar storms would punch holes in Earth's atmosphere, and this could hurt humans. Ozone holes, like that over Antarctica (which today are due to an entirely different cause related to man) could form as solar particles interact with the atmosphere in a cascade of chemical reactions.
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- These 'holes' would not be permanent, but might be present on one- to 10-year timescales, important enough to be a concern in terms of skin cancer rates.
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- A weak magnetic field could lead to the formation of ozone holes. Is there a connection between pole reversals and species extinctions? Even if the field becomes very weak, at the Earth's surface we are shielded from radiation by the atmosphere. Similarly as we cannot see or feel the presence of the geomagnetic field now, we most likely would not notice any significant change from a reversal.
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- Our technology definitely would be in danger, however. Even now, solar storms can damage satellites, cause power outages and interrupt radio communications. These kinds of negative influences clearly will increase if the magnetic field and thus its shielding function became significantly weaker, e.g. during a reversal.
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- One additional worry is that a weakening and eventual reversal in the field would disorient all those species that rely on geomagnetism for navigation, including bees, salmon, turtles, whales, bacteria and pigeons. There is no scientific consensus on how those creatures would cope.
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- Many of the disaster scenarios associated with geomagnetic pole reversals in popular imagination are pure fantasy, the scientists said. There definitely won't be any break-up or shift of the continents.
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- The first proof is the geologic record. When the last pole switch happened, no worldwide shifting of continents or other planet-wide disasters occurred, as geoscientists can testify to from fossil and other records.
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- The scientists explained that changes in the Earth's liquid core happen on a completely different distance and timescale than convection in the Earth's mantle (which causes Earth's tectonic plates to shift, moving the continents).
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- The liquid core does indeed touch the bottom of the mantle, but it would take tens of millions of years for changes in the core to propagate up through the mantle and influence the motion of the tectonic plates.
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- The geomagnetic field is currently weakening, possibly because of a growing patch of reverse-alignment in the liquid core deep beneath Brazil and the South Atlantic. The strength of Earth's magnetic field has been decreasing for at least 160 years at an alarming rate, leading some to speculate that we are heading toward a reversal.
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- The reversal might happen, or it might not Earth is too complex a system for scientists to know which outcome to expect. Either way, the process will drag on over the next few thousand years.
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- Earth's magnetic north pole, which has been wandering faster than expected in recent years, has now crossed the prime meridian. Magnetic north has been lurching away from its previous home in the Canadian Arctic toward Siberia at a rate of about 34 miles a year over the past two decades.
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- The latest model of the Earth's magnetic field, released December 10, 2020, predicts that this movement will continue, though likely at a slower rate of 25 miles each year.
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- Earth's magnetic field is produced by the churning of the planet's iron outer core, which produces a complex, but largely north-south magnetic field. For reasons not entirely understood but related to the planet's interior dynamics, the magnetic field is currently undergoing a period of weakening. That's why magnetic north is drifting.
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- As of February, 2019, magnetic north was located at 86.54 N 170.88 E, within the Arctic Ocean. Magnetic south similarly does not line up with geographic south; it was at at 64.13 S 136.02 E off the coast of Antarctica as of February, 2019.
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- Scientists release a new version of the World Magnetic Model every five years, so this 2020 update was expected. In February 2019, though, they had to release an update ahead of schedule due to the fast clip of magnetic north's movements.
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- The 2020 model shows the "Blackout Zone" around magnetic north where compasses become unreliable and start to fail because of the proximity of true north. The new maps also show magnetic north east of the prime meridian, a boundary the pole crossed in September 2019.
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- The prime, or Greenwich, meridian is the meridian that was set as the official marker of zero degrees, zero minutes and zero seconds in 1884. It runs through the Royal Observatory at Greenwich in England.
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- It's currently unclear whether Earth's magnetic poles are headed for a flip-flop ,switching north and south , or, whether the magnetic field will soon strengthen again. Both events have happened in Earth's history without any notable effect on biology.
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- However, modern navigation systems rely on magnetic north and will have to be recalibrated as the poles continue to wander. Already, for example, airports have had to rename some of their runways, which have names based on compass directions.
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- Stay tuned and don’t get lost using that Boy Scout compass.
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February 28, 2021 EARTH - magnetic field flips 3068
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