Reversal of Earth's Magnetic Field-(Hey Algore read this)

Projects in Scientific Computing ^ | N/A | Gary Glatzmaier, Los Alamos National Laboratory

[King Prout]

actually, the magnetic poles have shifted significantly within the last 40 years, which is why maps and charts older than a few years are unreliable for navigation. Hell, on some land nav courses I went through in ROTC, they issued multiple degree corrections to the stated magnetic north on maps less than 15 years old.
moreover, you misread: the article stated very plainly that polar flux is highly irregular - sometimes rapid, sometimes quite static for very long periods.

[SunkenCiv]

The shift itself happens in circa 1000 years -- but there are long periods of stability, lasting 10,000 to millions of years. Of course, these duration estimates are based on remanent magnetism in old volcanic floes.

[caveat emptor]

The difference between magnetic and true is magnetic variation, not declination.

You should really learn to read before you write.

"Magnetic declination" is the phrase I used, and is correct. "Variation" as well has more than one meaning in this context, but it all works out well if you're careful in what you read and write. Try it sometime, here, for example.

[SunkenCiv]

related topics, going back about four years, listed in alpha order:

Canada: Our North loses the Pole ~~ moving toward Siberia
Edmonton Journal | Friday, June 17, 2005 | Nathan VanderKlippe
Posted on 06/17/2005 2:18:11 PM EDT by Ernest_at_the_Beach
http://www.freerepublic.com/focus/f-news/1425129/posts

Earth Loses Magnetism
BBC | 1-1-2004 | Molly Bently
Posted on 01/01/2004 12:49:40 PM EST by blam
http://www.freerepublic.com/focus/f-news/1049919/posts

Earth's Magnetic Pole Drifting Quickly
BREITBART.COM | December 9, 2005 | ALICIA CHANG
Posted on 12/09/2005 8:05:37 PM EST by mlc9852
http://freerepublic.com/focus/f-news/1537489/posts

Earth's magnetic poles on verge of flipping
World Net Daily | December 12, 2003
Posted on 12/13/2003 11:38:30 PM EST by gitmo
http://www.freerepublic.com/focus/f-news/1039977/posts

Movement Of Earth's North Magnetic Pole Accelerating Rapidly [No Doubt Bush's Fault!]
Science Daily | 2005-12-09 | Oregon State University
Posted on 12/09/2005 3:25:52 PM EST by Brilliant
http://www.freerepublic.com/focus/f-news/1537329/posts

Sun's rays to roast Earth as poles flip
The Observer (U.K.) | 11/10/2002 | Robin McKie
Posted on 11/09/2002 8:59:37 PM EST by Pokey78
http://www.freerepublic.com/focus/f-news/786012/posts

When the compass suddenly points south ( Magnetic Pole Flip, latest SHOCKING news)
German state television | January 5
Posted on 01/05/2005 7:29:38 PM EST by Truth666
http://www.freerepublic.com/focus/f-bloggers/1314846/posts

[wyattearp]

It's called the Angle of Declination, and it most DEFINATELY changes.

No BS. I have to adjust the declination on my compass, and the compass on my watch, every year. Eight years ago, it was W 19.8 degrees. Now it is W 16 degrees. Magnetic north is variable.

[Kenny Bunk]

(Variation) It's the difference between magnetic north and true north

Correct. Variation is natural. Compasses vary depending upon where one is. Deviation is caused by electro-magnetic fields, magnetic materials, iron pots and pans, engine blocks, Steel hulls, etc.

Nature varies, man deviates. It's also why the magnetic compass is used in dead reckoning. Sooner or later every sailor who depends upon it will be dead; hopefully from natural and not deviant causes.

Doubtless your previous correspondent was navigating by solar fixes, or perhaps using a Bumstead Solar Compass.

[RightWhale]

So they say.

[RightWhale]

It is very lively, not at all like the slow movement of the magma under the crust. The north magnetic pole moves continually 200-300 mph over an area radius 300 miles.

[pabianice]

(Variation) It's the difference between magnetic north and true north Correct. Variation is natural. Compasses vary depending upon where one is. Deviation is caused by electro-magnetic fields, magnetic materials, iron pots and pans, engine blocks, Steel hulls, etc. Nature varies, man deviates. It's also why the magnetic compass is used in dead reckoning. Sooner or later every sailor who depends upon it will be dead; hopefully from natural and not deviant causes. Doubtless your previous correspondent was navigating by solar fixes, or perhaps using a Bumstead Solar Compass.

Wrong again, I'm afraid. My pevious navigating was through the use of cellestial, DR, INS, Doppler/Airmass, Pressure lines of position, Consolan, Omega, drift meter, and various other methods. I was a P-3 Patrol Plane Mission Commander and PQS instructor navigator in the US Navy, which, you'll have to admit, has a fair amount of practical navigation under its belt.

BTW, DR comes from deduced, not "dead."

[Max in Utah]

Notice the thirty-some million year wide band during the Cretaceous period:

I wonder why the field didn't reverse during that very long time?

[Veto!]

I wonder why the field didn't reverse during that very long time?

According to Algore, because the Cretaceons didn't drive SUVs.

[Nowhere Man]

actually, the magnetic poles have shifted significantly within the last 40 years, which is why maps and charts older than a few years are unreliable for navigation. Hell, on some land nav courses I went through in ROTC, they issued multiple degree corrections to the stated magnetic north on maps less than 15 years old.
moreover, you misread: the article stated very plainly that polar flux is highly irregular - sometimes rapid, sometimes quite static for very long periods.

I have an old National Geographic magazine from 1967 and there was a chart in there on where the North Magnetic Pole wandered from the Time of Christ to 1967. There was a lot of movement and it seems that it picked up in the 20th Century.

I remember a couple of times I kept seeing an AWACS plane fly around my house, I live in an air pattern near Greater Pittsburgh Int'l Airport and the AWACS kept coming in on approach and circling around many times before it landed. I asked my neighbor, who was in the Penna Air Nat'l Guard as a mechanic of our planes from the P-51 Mustang to the A-7 fighters, he told me that the Air Force checks the runways, registers and makes corrections for changes in magnetic north. Dunno why they need an AWACS plane to do it but well, I guess the Air Force has its reasons.