
Earth’s magnetic field is acting up - evo_9
https://www.nature.com/articles/d41586-019-00007-1?utm_source=twt_nnc&utm_medium=social&utm_campaign=naturenews&sf205680051=1
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thangalin
"Pottery jugs from between the eighth and second centuries B.C. bear
administrative stamps that changed with the political situation. Unbeknown to
the people firing these jugs, the act of heating locked information about the
Earth's geomagnetic field into minerals present in the clay. Because the
stamps provide precise information about when the pots were fired, the study
allows a detailed look at geomagnetic changes over 600 years."

[https://www.livescience.com/57868-earth-magnetic-field-
spike...](https://www.livescience.com/57868-earth-magnetic-field-spike-
ancient-times.html)

~~~
medius
This is one of the most amazing things about humans to me. I marvel at how
it's possible to get so much information about our universe by observing so
little. Astronomy is another field that I'm really impressed with. It's
possible to infer things about galaxies, stars, planets, etc. just buy
observing some light coming from them to our little blue planet. Absolutely
crazy.

How many such techniques we haven't even discovered or technology is not there
to observe such things?

I really enjoyed reading Our Mathematical Universe by Max Tegmark that
explores such things.

~~~
lubujackson
I always love reading the crazy new techniques for extracting text from rotten
old paper and papyrus. I distinctly remember reading a few months back an
article about someone detecting trace chemicals from an old pocket bible or
something, and deduced the owner had liver disease or something equally
insane. wish I could find that article!

~~~
klenwell
I was just about to post the link to this New Yorker article in response to
GP's question. I believe this is the one you're referring to:

[https://www.newyorker.com/magazine/2018/11/26/do-proteins-
ho...](https://www.newyorker.com/magazine/2018/11/26/do-proteins-hold-the-key-
to-the-past)

 _Under the right conditions, proteins can survive for millions of years. In
recent years, proteomic studies of art works and archeological remains have
yielded biological information of startling clarity, revealing gossamer-thin
layers of fish glue on seventeenth-century religious sculptures and
identifying children’s milk teeth from pits of previously unrecognizable
Neolithic bones._

~~~
lubujackson
Yes! Thank you, it was somehow impossible to Google this.

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falcolas
Oddly enough, this has a sizable impact to general aviation. Heading is
typically measured using a gyro, but the heading values are calibrated to
magnetic north (typically via a magnetometer or manually against a compass).

The creep of the magnetic field is noticeable in particular in the numbering
of runways - they are numbered according to their heading. Some runways that
have existed for a few decades are, accordingly, off by a few degrees. An
older runway numbered "35" may have an actual approach heading of 340 (340
degrees from magnetic north). Not a huge problem when flying by eye, but it
has the capability of causing some confusion when flying using instruments.
Alternately, the runway numbers can even change.

As for GPS, this won't solve the problem either, since GPS can give you a
"true" flight path using the movement over time, which with wind will not
always match the actual heading of the aircraft due to wind.

~~~
souprock
This is pretty sad. For at least decades, maybe even centuries, there have
existed compasses that let you rotate the "north" indicator to match the
current local magnetic declination. Adjusting as you travel is no different
than the pressure adjustments that pilots make for altimeters. There is no
good reason we couldn't have all of the airports using geographic north. That
one is far more resistant to change, with continental drift and Earth axis
wobble being far slower than magnetic pole movement.

~~~
repiret
Ease and reproducibility of the measurement is more important than its
absolute accuracy. Whisky-ball magnetic compasses are cheap and easy to build,
and have been throughout aviation's history, and don't require access to an
accurate geomagnetic survey to use.

Its interesting that you mention pressure adjustments, because:

* Above 18,000 feet in the US, you don't make pressure adjustments - because its more important to know that your neighbors in the airspace are measuring their altitude the same way you are than it is to know exactly how far off the ground you are. In other parts of the world the threshold is lower, sometimes much lower.

* Airspeed is also measured with a pressure instrument, whose accuracy is affected by the density of the air, which in turn is affected by temperature and altitude. But the speed limits in the regulations, and the speeds ATC might tell you to fly, are all based on the uncorrected output of the pressure instrument - "indicated air speed", as its called. You only try to adjust for altitude and pressure when using the airspeed for navigation.

~~~
snuxoll
Sectional charts also display magnetic variation, there's no reason to change
the instruments when you can do basic math.

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feniv
Earth's magnetic pole has been known to switch sides in the past.
[https://en.wikipedia.org/wiki/Geomagnetic_reversal](https://en.wikipedia.org/wiki/Geomagnetic_reversal)

"183 reversals over the last 83 million years... A brief complete reversal,
known as the Laschamp event, occurred only 41,000 years ago during the last
glacial period. ... Geologists first noticed that some volcanic rocks were
magnetized opposite to the direction of the local Earth's field.".

~~~
darkerside
When this happens, does the magnetism "rotate" around the Earth, or does it
fade out and fade back in reversed?

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idbehold
Closer to fading out and back in.

~~~
michaelg7x
Does this mean anything for the protection the planet receives from cosmic
rays or solar wind?

~~~
techas
Indeed. Some people believe these “unshielded” periods might had some
influence on the evolution of the species. Without those, the rate of change
is just not enough to get to humans...

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NeedMoreTea
I've read a number of pieces over the years that a geomagnetic reversal might
be near, and there have been flips as short as a couple of hundred years.
Where "near" may be in my lifetime or in the next 500 years.

So we may not know why it's moved more than model, but I don't think we should
be unduly surprised.

Here's one recent piece implying a switch could be sooner rather than later:
[https://www.extremetech.com/extreme/192522-earths-
magnetic-f...](https://www.extremetech.com/extreme/192522-earths-magnetic-
field-could-flip-within-our-lifetime-but-dont-worry-we-should-be-ok)

~~~
ams6110
So what exactly does that mean? If I'm driving from Chicago to Milwaukee will
my compass say I'm heading South?

~~~
faissaloo
I'd guess it would cause the mass death of animals that use the poles to
navigate.

~~~
Tharkun
Wikipedia seems to suggest this is unlikely:

> Hypotheses have also advanced toward linking reversals to mass
> extinctions.[47] Many such arguments were based on an apparent periodicity
> in the rate of reversals, but more careful analyses show that the reversal
> record is not periodic.[17] It may be, however, that the ends of superchrons
> have caused vigorous convection leading to widespread volcanism, and that
> the subsequent airborne ash caused extinctions.[48]
> ([https://en.wikipedia.org/wiki/Geomagnetic_reversal](https://en.wikipedia.org/wiki/Geomagnetic_reversal))

------
petre
Mads Faurschou Knudsen and Peter Riisager, Department of Earth Sciences,
University of Oxford, Parks Road, Oxford OX1 3PR, UK. Pages 71-74.

 _Based on an observed correlation between the Earth 's magnetic dipole moment
and oxygen isotope paleo-precipitation records from caves in Oman and southern
China, Knudsen and Riisager suggest that the Earth's magnetic field may have
influenced the amount of rainfall in low-latitude regions during the past 5000
years. The physical mechanism that underpins the geomagnetic-climate link is
provided by the cosmic-ray-climate theory, which suggests that galactic cosmic
ray (GCR) particles entering the atmosphere influence the formation of low-
altitude clouds and, in turn, climate. The geomagnetic field shields the Earth
from GCR particles and, according to the cosmic-ray-climate theory, it
therefore has the potential to influence cloud formation, rainfall, and
climate. Since the amount of GCR particles entering the atmosphere is also
modulated by the Sun, the cosmic-ray-climate theory is central to the ongoing
scientific debate regarding the role of the Sun in climate change. Knudsen and
Riisager lend support to the notion that variations in the Earth's magnetic
field may influence the climate of our planet. They also deliver independent
support for certain aspects of the cosmic-ray-climate theory._

[https://www.eurekalert.org/pub_releases/2009-01/gsoa-
jgm0108...](https://www.eurekalert.org/pub_releases/2009-01/gsoa-
jgm010809.php)

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chiefalchemist
> "On 15 January, they are set to update the World Magnetic Model, which
> describes the planet’s magnetic field and underlies all modern navigation,
> from the systems that steer ships at sea to Google Maps on smartphones."

Boggles the mind to think that Mother Nature is the foundation for such
significant technology.

If only the Twilight Zone was still around to do an episode on the magnetic
north suddenly going MIA. It has gone south (literally) a couple times I
believe.

~~~
vanattab
"Boggles the mind to think that Mother Nature is the foundation for such
significant technology."

As best I can tell Mother Nature is the foundation of ALL technology...

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lostmsu
On the picture, the movement of the pole slightly resembles a pendulum: it is
slow at the beginning far from the geographic pole, and it speeding up as it
nears it. Makes perfect sense, actually.

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exabrial
Being a son of a geologist, I found it fascinating we could tell from geologic
history how many times the earth's magnetic field has flipped. Turns out we're
long overdue for a reversal.

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ComputerGuru
> Update, 9 January: The release of the World Magnetic Model has been
> postponed to 30 January due to the ongoing US government shutdown.

This article isn't much without the accompanying model.

~~~
peterwwillis
Since the US is on extended winter vacation, maybe China or Russia can
maintain the world magnetic model?

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golemotron
It was foretold:
[https://www.imdb.com/title/tt0298814/](https://www.imdb.com/title/tt0298814/)

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phkahler
>> In 2018, the pole crossed the International Date Line into the Eastern
Hemisphere. It is currently making a beeline for Siberia.

I knew Putin was a super villain. Now he's stealing the north pole!

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olivermarks
Article linked is truncated, last sentences lifted from here
[https://www.nature.com/articles/d41586-019-00007-1?utm_sourc...](https://www.nature.com/articles/d41586-019-00007-1?utm_source=twt_nnc&utm_medium=social&utm_campaign=naturenews&sf205680051=1)

~~~
NeedMoreTea
That's a much better article, free of claims of scientific bafflement. :)

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macawfish
So it begins

