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North Magnetic Pole just crossed Prime Meridian
#1
Gentlemen,  I found the following piece kind of interesting.

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 (55 kilometers) a year over the past two decades. The latest model of the Earth's magnetic field, released Dec. 10 by the National Centers for Environmental Information and the British Geological Survey, predicts that this movement will continue, though likely at a slower rate of 25 miles (40 km) each year. 
This model is used to calibrate GPS and other navigation measurements. 

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

As of February 2019, magnetic north was located at 86.54 N 170.88 E, within the Arctic Ocean, according to the NCEI. (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.) 

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. 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, according to Newsweek. 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;iIt runs through the Royal Observatory at Greenwich in England. 

Related: What If Earth's Magnetic Poles Flip?

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. 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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#2
Rumata,

That's a very interesting post. The explanation of GPS is something that always has confused me, now, it makes more sense.

As to the earth's magnetic pole shifting- yes, it's speeding along and is very much a wonder to see its path. We often think that everything in nature and static- not changing. The pole movement is a curiosity.

Thank you for posting this!

Fred
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#3
(12-22-2019, 03:37 AM)Fred_B Wrote: Rumata,

That's a very interesting post.  The explanation of GPS is something that always has confused me, now, it  makes more sense.

As to the earth's magnetic pole shifting- yes, it's speeding along and is very much a wonder to see its path.  We often think that everything in nature and static- not changing.  The pole movement is a curiosity.  

Thank you for posting this!

Fred
Thank you,  Fred!

I found whatever is related to the origin of the Earth' magnetic field quite fascinating.  No real explanation of the most basic phenomenon of our ( and "our" means everything going through the cycle birth-death, from cockroaches to politicians) everyday existence. No Hubble telescope inside the lythosphere.  The origin  of very high temperature inside the Earth's core, iron-nickel we told, supposed to be radioactive decay.  Why?  Because there is no another explanation.  So far.  And by the way the origin  of so-called natural  magnetism,  lode stones,  isn't really explained either. SO, any new info  about it is interesting.  And I hope, not just for me, but to other members of this Forum  also.
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#4
I have a local marine map dating a few years.  It's compass rose says 0 degrees difference between true north and magnetic.

Yesterday I was reviewing some nautical maps of my area on openseamap.org.  Therein,  I was surprised to see, the variation had changed from 0 to 1.7 degrees west.

There are at least two reasons one might have to equate polar and magnetic north. Either changing map true course to compass course, or changing magnetic bearings to true map bearings. 

The thing to remember is that when going from true map to magnetic compass course, east is least and west is best.  In other words if  you plot a true course on the map, and your area has easterly variation, then subtract the variation from the true which gives the helmsman the compass course to steer.

If taking, lets say, a compass bearing of a lighthouse and transfer it to a map, then add the easterly variation to get the true map bearing.

From map to compass - east is least (subtract), and west is best (add).
From compass to map - the opposite.

Simple
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#5
Had no idea the magnetic pole moved that much. Speaking of compasses- compasses that are useful in one hemisphere (Northern or Southern) are useless in another....from what I've heard.

Fred
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#6
(02-12-2021, 01:19 AM)Fred_B Wrote: Had no idea the magnetic pole moved that much.  Speaking of compasses- compasses that are useful in one hemisphere (Northern or Southern) are useless in another....from what I've heard.

Fred

Hi Fred

I guess its just one of those things we have to be aware of.

When I started flying the max variation was about 15 degrees.  Looks like these days it's about 5 degrees but increasing. However, if you confuse east and west variation you could double the error. 

Keeping track of Variation kinda makes navigation interesting. Coastal piloting would be boring without it, as was the case here in cebu.  I'm happy to see my variation change - I get to update my important magnetic bearing fixes.

Do you have any references concerning the north and south compasses?

Cheers
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#7
(02-12-2021, 07:51 AM)pabrides Wrote:
(02-12-2021, 01:19 AM)Fred_B Wrote: Had no idea the magnetic pole moved that much.  Speaking of compasses- compasses that are useful in one hemisphere (Northern or Southern) are useless in another....from what I've heard.

Fred

Hi Fred

I guess its just one of those things we have to be aware of.

When I started flying the max variation was about 15 degrees.  Looks like these days it's about 5 degrees but increasing. However, if you confuse east and west variation you could double the error. 

Keeping track of Variation kinda makes navigation interesting. Coastal piloting would be boring without it, as was the case here in cebu.  I'm happy to see my variation change - I get to update my important magnetic bearing fixes.

Do you have any references concerning the north and south compasses?

Cheers

padbrides,

This is just a quick explanation;

https://www.earthlearningidea.com/PDF/197_Compass.pdf


It seems a compass needle that tries to point to the North magnetic pole will have the compass card dip down when it's below the equator.

Carlos
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#8
(02-12-2021, 12:47 PM)CarlosPindle Wrote:
(02-12-2021, 07:51 AM)pabrides Wrote:
(02-12-2021, 01:19 AM)Fred_B Wrote: Had no idea the magnetic pole moved that much.  Speaking of compasses- compasses that are useful in one hemisphere (Northern or Southern) are useless in another....from what I've heard.

Fred

Hi Fred

I guess its just one of those things we have to be aware of.

When I started flying the max variation was about 15 degrees.  Looks like these days it's about 5 degrees but increasing. However, if you confuse east and west variation you could double the error. 

Keeping track of Variation kinda makes navigation interesting. Coastal piloting would be boring without it, as was the case here in cebu.  I'm happy to see my variation change - I get to update my important magnetic bearing fixes.

Do you have any references concerning the north and south compasses?

Cheers

padbrides,

This is just a quick explanation;

https://www.earthlearningidea.com/PDF/197_Compass.pdf


It seems a compass needle that tries to point to the North magnetic pole will have the compass card dip down when it's below the equator.

Carlos

Hi Carlos,

I'm pretty sure the fact checkers at whatever school is using that curriculum haven't been too particular...  Just goes to show the rediculous nonsense union teachers are pouring into kids today.

There is such a thing as dip, but it is not very pronounsed.. Compass cards in ships have a greater difficulty countering pitch and roll - not to mention aircraft.  The south end of a needle is attracted  south in the same way the north needle is to the north.  The variation in dip is practically insignificant.   I think the writer took a few liberties with the photos to perhaps dramatize the effect.

Cheers
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