Compass declination rapidly changing...

[shangchi108]

Yup. California might fall into the ocean too.:barf:

Fact is, the rest of the country will fall into the Atlantic. Good riddance, too!

 

[Warriorsociologist]

As the only living actor who once was Governor of California?

^___^

^ and "Happy 100th" to the one no longer with us.

 

[gregorio]

I think it is well understood that the pole does shift, the geology folks at my university use samples from old lava flows to measure the magnetic properties to see what direction the local field pointed when it solidified.

The real danger of this is cosmic rays not being effectively shielded by the earths magnetic field and not so much the navigation thing.

 

[x39]

The real danger of this is cosmic rays not being effectively shielded by the earths magnetic field and not so much the navigation thing.

I never thought of that, our magnetic field is what makes life on earth possible.

 

[Watchful]

The real danger of this is cosmic rays not being effectively shielded by the earths magnetic field and not so much the navigation thing.

There is NO chance of the magnetic field disappearing. The poles may shift (and have many times) but the magnetic field is created by the molten metallic core of the earth spinning at high speed. That isn't about to stop for billions of years.

As you know, the magnetic poles don't line up with our geographic poles except coincidentally. The earth spins under its own momentum from its formation 5+ billion years ago; the molten core spins just a little bit faster (like an ice skater with the arms tucked in) than the surface of the earth. As a result, there is always a discrepancy between the two.

The spinning molten core turns the earth into a massive magnet, as you also know. Natural magnets have clear poles. Because of the discrepancy between the magnetic core and the surface, the poles wander.

Sometimes they flip entirely, as magnets in fluids are wont to do. The process is not instantaneous, and will take a very long time to do--or so we think. Since it hasn't happened in thousands of years, no one is exactly sure, but the math seems to check out okay.

Compasses will need to be recalibrated (but they are every year; nice links, guys! Like them!). Planes and commercial sea craft all use GPS, which will NOT be affected by a pole shift.

And because the poles won't flip north/south to south/north, they can wind up anywhere. You might find the NMP is now in Nebraska, or Rio, or Mumbai: meaning that these folks might suddenly be treated to auroras!

If it happens, it won't be catastrophic. It might be expensive to adjust compasses, remap the magnetic lines, and chuck out thousands of surveys, but North will still be up on maps, and your compass can be adjusted like always. Within a couple years, everybody will remark about the old days when compasses pointed nearly North.

 

[gregorio]

The origin of the earths field is not agreed to by everyone and there are problems with the dynamo model. That being said I don't think we can be sure the earths field will maintain a constant intensity, time will tell.

 

[Watchful]

Gravit isn't agreed to by everyone; however, the physics behind the origin of the earth's magnetic field is pretty well understood... shows on television notwithstanding that like to scare folks otherwise.

There are indeed fluctuations in intensity, but these are extremely minor and short-lasting. They in no way portend or represent a potential life-ending shutdown of the magnetic field.