http://news.yahoo.com/s/space/20100302/sc_space/chileearthquakemayhaveshorteneddaysonearth

With the increase in quakes, my buddies over at Nasa are saying that we have shifted axis north to south by 33 feet, which begs the question looking down the road as the offset posed on our compasses. They have been saying by 2012 that there could be a magnetic shift from North to South (flipped). I know a lot of us rely on compasses which tends to wonder about what is needed to stay on top of Geo shifting trends that affect the magnetic polarity of the planet, or is it just a lot of ranting trying to get everyone worked up over nothing.

Magnetic deviation has always been a variable.
Aviation charts (at least!) show the latest value for deviation in the area it covers. Over time even runway numbers have to change as the runway no longer points to the same magnetic heading.

If the poles flip I'd expect that to make a really big BUMP!

If the poles flip, would not the magnetic forces still be aligned N-S, with only reversed polarity? We will alertly realize, by noticing the heavens, that we now have a south pointing compass.....

Ultimately if the poles flipped your compass would still work, you would just have to remember to look at the black end. There will be a confusing few 100-1000 years during the change.

The Chilean earthquake will change the tilt of the earth very slightly - about 3inches. But that doesn't affect the relative position of magnetic and true north.

It will also make the day slightly shorter.

Gentlemen,

Pole reversals have happened many many times historically.
We just get them on a geological time scale.

When it happens, it takes at least thousands of years to complete.
Who knows the cycles are based on so called superchrons.
Some models have it taking 50,000 years.
Anyway no one alive today needs to worry about that.


It is not a sudden phenomenon.

Worst case scenario just use declination of 180 degrees and all the regular compass math will work.

better concern what happens to the Van Allen belts and our shield against solar winds. Could really cause some problems for satellites and then with GPS down, you really need a compass too.


A lot more likely and more challenging things can happen, like earthquakes and of course astro-geo collisions which really mess things up.

Should be fun.

check out "physorg.com" for the story,if i read it right the change is 3 inches..the quake in 2004 shifted it 2-something.

What the story is talking about shifting is not the magnetic pole. They are talking about the line through the center of the earth that everything is balanced around.
The magnetic pole is not even at the north geographic pole and it wanders around the Islands inside the Canadian Arctic. It changes all the time and you have to correct old maps to new readings.


Magnetic declination calculators:
Canada
http://geomag.nrcan.gc.ca/apps/mdcal-eng.php
USA.
http://www.ngdc.noaa.gov/geomagmodels/Declination.jsp

No, he's saying he did some calculations and guesses that might be the result. Nobody's measured it yet.

(I'm skeptical - planets are very big and massive things, and earthquakes are very small things that make very little net difference, so much so that 1 in 10^6 feels too big)


The magnetic poles do shift, but almost certainly very slowly, over hundreds to thousands of years, perhaps longer. It's possible, though unlikely, that a slow transition has already begun.

The problem isn't "on the other side" where the poles are flipped but rather in the middle of a transition when the magnetic field field will be weak and might temporarily sprout several "poles" in odd places. We don't really know since it's never happened in historic times for us to see.

But the emphasis is that this is almost certainly slow on a human time scale. At worst I think you might need to carry around a cheat-sheet on how to interpret your compass based on your location, and update that every decade or so. If a "magnetic pole" appears in your neighborhood then a compass is useless there temporarily.

Just curious, what is the evidence for the 2012 reversal?

Hollywood

The poles have been moving rather fast recently (the last few decades) but we only have data from the last 500years of where they were so it's hard to tell if this is typical before a shift.

Shifts seem to occur every 100,000 - 10,000,000. We are a little overdue a switch based on the geological record, but the changes aren't regular like an astronomical event, they are more chaotic.

According to this:
http://scienceblogs.com/builtonfacts/2010/03/spinning_up_the_earth.php?id=146589

The pole shifted all of three inches and the day got shorter by 1.26 microseconds. So if your feeling a bit lost and short of sleep you have an excuse.

NPR had a bit on it this morning that noted that neither the three inches nor the shorter day have been observationally verified. Those values are theoretical and are apparently too small, in relation to normal variation, to be show up.

Thanks, I appreciate the info, I was more concerned that changes in the earths parameters (axis, rotation, etc..) would cause a loss in our navigation capabilities and of course more important disasters may follow(increase in natural events. I'm aware the magnetic spots through the chart and was thinking that anytime you make a major shift to a big axis, your readings will adjust as well. Kinda of like putting a magnet on a table and looking at a reading on your compass and then move the magnet and of course the compass follows suit. One thing I'm not realizing is that this may occur over years and not something that will happen in days, so I'm not in a region on travel and wake up in the morning and wonder why my compass is pointing a complete direction than I had traveled the day before. I guess if this happens there are a lot more problems to worry about than this. Thanks for the input.

Those are estimates, not measurements. The Earth is nowhere near uniform, so until someone tries a measurement you never know if the estimate's assumptions are right.

The effect is so tiny it is probably lost in the noise of other, larger, influences. The millisecond pulsar observers *might* but able to detect the change if they were running a serious of observations at the time.

In terms of preparedness and compass usage - an unrelated issue - the word is Slow. When a geologist says "a sudden pole reversal", "sudden" means thousands to millions of years.

I knew it!

This forum is full of deviant talk.

LOL! Thanks, I need that!
-Blast

The rotation of the earth is measured continually fairly accurately by the IERS. The 1.2 microSec change in the length of a day due to the quake is small compared to the 5-10 millisecond variation over the year. But it is measurable.
Of course unless you are doing VLBI astronomy it's totally irrelevant!


We don't know how long a pole shift takes but it is fast in geological terms. Poles can change as often as every 200,000 years and we don't see a lot of intermediate values so it make take as 'little' as a few 1000 years.

There are theories that it is fast enough that the Van-Allen belts (which shield us from cosmic radiation) aren't seriously affected, which is why we don't see any biological/fossil evidence related to the flips.