Earth's Magnetic North Pole Continues Drifting, Crosses Prime Meridian

[Judi Lynn]

By Stephanie Pappas - Live Science Contributor 7 hours ago



Earth’s magnetic field protects us from the solar wind by deflecting the charged particles.
(Image: © Shutterstock)

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.)

More:
https://www.livescience.com/earth-magnetic-north-passes-prime-meridian.html

[lastlib]

1. adjust your compasses accordingly.

Fifty years ago, my topographic quadrangle had a magnetic declination of 6 degrees; as of 2009, it was four degrees. I'll have to do some digging to see if it has varied any more.

I don't understand the part about the mag-north pole crossing the prime meridian, which runs through England. Surely it did that several millenia ago.

[muriel_volestrangler]

2. I think what they mean is that at Greenwich, magnetic north has crossed from one side

of the prime meridian to the other - that's how the Newsweek article put it in September:

Compasses in Greenwich, London, are about to point to the "true north" for the first time since 1660—when Charles II was on the throne and the first English settlers were setting about colonizing the Americas.
...
For the last 360 years, compasses in London have pointed to the west of true north. Over the next two weeks, experts at the British Geological Survey say the two lines will match up at the Royal Greenwich Observatory—the home of the Prime Meridian line (the zero of longitude).

The true and magnetic north are expected to line up for a short period before moving to the east. "By 2040, all compasses will probably point eastwards of true north," Beggan said in a statement.

Earth's magnetic north pole used to move at a rate of about nine miles per year, but it has sped up in recent decades: "The magnetic north pole has moved quite fast in the last 20 years," Beggan told Newsweek. "Over the past five years it has moved close to the geographic North pole but on the far side of it as we see it from the U.K. Hence the line of zero declination is now moving across the U.K. and Ireland."

https://www.newsweek.com/magnetic-north-pole-compasses-uk-1457591

(because magnetic lines don't line up in a perfectly-divide sphere, this didn't happen precisely when 'magnetic north' - which is where a magnet points straight down - crossed 180 degrees longitude:

[lastlib]

3. ah, thanks!