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vwb2022 t1_ja9b4lv wrote

The only thing that is affected is that the magnetic North and geographic North will not align anymore, so a magnetic compass will not be as useful anymore, as direction of the North will depend on geographic location. There is no effect on the Earth rotation or any other physical effects.

I don't think there will be serious day-to-day effects, most navigational systems use some version of GPS, which aligns through satellites rather than magnetic compass. Weakening of the magnetic field itself may be harmful as it protects the surface of the Earth from charged particles coming from the Sun, such as those created by solar eruptions. These can sometimes disrupt electrical systems on the surface, but their magnitude is rarely sufficient to cause real concern.

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kompootor t1_ja9i073 wrote

It should also be noted that time during which a geomagnetic reversal takes place is by any estimates 2k--12k years. So even if we're headlong into it, Comparatively, magnetic North's speedy yearly drifting would overshadow any observation of an overall movement of the poles to flip (if the pole's wobbles were a consistent-direction drift then it would be in the Antarctic within 400 years.) And because airport runways are numbered according to their magnetic compass direction (instead of true), the wobbly North pole means regular runway repainting, costing the aviation industry upwards of tens of dollars per year!

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EmeraldAlicorn t1_ja9sjyz wrote

CGP grey has an amazing video on all of this that might be helpful for OP. I it's called "the simple secret of runway digits"

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Spiderbanana t1_ja9xng4 wrote

Tens of dollars a year? Damn they'll surely go bankrupt soon

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aspheric_cow t1_ja9khrf wrote

> most navigational systems use some version of GPS, which aligns through satellites rather than magnetic compass

Actually no, compass and GPS can't substitute for one another. GPS tells you your location, but not your orientation. If you are standing still, GPS won't tell you which direction you are facing (or which way the front of your vehicle is pointing), but a compass can.

If you are moving, GPS can tell you which direction you are moving, but on ships, airplanes and spacecraft, the direction you are moving is not necessarily the direction your vehicle is pointing. So you still need a compass. A gyroscope also works for this, but gyroscopes drift over time, so a magnetic compass is a more accurate long-term reference.

Spacecraft often use star trackers or sun sensors for determining the orientation (attitude), but some do use magnetic sensors. And also, most satellites rely on magnetic torquers to change their attitude. Reaction wheels (aka flywheels or gyroscopes) are also used, but they eventually saturate (moving as fast as they can) and eventually they need to offload the angular momentum to something external. That something is usually a magnetic torquer, which is an electromagnet that basically pushes against the Earth's magnetic field to rotate the spacecraft. Thrusters also work for this purpose, magnetic torquers are far simpler and cheaper, so most satellites in low orbit just has magnetic torquers, not thrusters.

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vwb2022 t1_ja9ljuv wrote

Yes, modern devices use a magnetometer to determine the direction of the North. But with a GPS you know your location relative to the magnetic pole and you can determine your direction of travel using the magnetometer and software to correct the magnetic pole drift. So GPS can tell tell you your direction of travel, albeit indirectly by correcting for your position relative to the drifting magnetic pole.

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Artanthos t1_jaa0xo2 wrote

Airplanes use several different systems.

Yes, they do use gyroscopes, and they do get periodically recalibrated.

Doppler radar is another system. On airport approaches you have TACAN.

All of these systems allow the pilot to make course corrections.

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LoveandRice t1_jaakohs wrote

They do but as an air traffic controller in busy approach airspace, I will say that 70% of our instructions are headings. That would really mess up my job

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Artanthos t1_jaazdsk wrote

All my experience is on the other end.

I was an aviation electronics technician. I worked on the hardware.

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Think_Job6456 t1_jaaeu81 wrote

Is there potential for disaster involving magnets? I’m not sure to what extent they are used, if at all, in modern devices.

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aspheric_cow t1_jaesip2 wrote

No, the Earth's magnetic field is too weak to affect the operation of devices that use magnetic forces. If it disappears or reverses, things will work fine.

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Strength-InThe-Loins t1_jaan9up wrote

Magnetic north and geographic north already don't align. That's the first thing they teach you in compass class.

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Tim_the_geek t1_ja9ghvr wrote

I respectfully disagree with one of your points. You say there will be no effect on the Earth's rotation if the magnetic pole shifts. I feel that there is quite a bit of "new magnetic" material on earth that was created during the current pole locations. These magnetic rocks in the crust have a polarity, when the core's magnetic field changes, I feel that the portions of the crust that have magnetic material in them will seek to realign with the NEW N-S orientation causing the earth's crust (or sections) to move.

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AnarchistAccipiter t1_ja9h6qw wrote

No.

The magnetic poles wander all the time, no parts of the earth's crust are affected.

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capt_yellowbeard t1_ja9jwg1 wrote

Succinct and well stated.

I’ll add that there is clear alignment “striping” of magnetic particles on the ocean floor. So by drilling different parts of the sea floor one can see which direction north and south were when the magma that makes up the sea floor was deposited. Once it solidifies, however, no further change occurs.

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supersonicpotat0 t1_ja9ksfm wrote

There is a easy way to test for this. Set a magnet on your desk. Now, rotate it 180 degrees, and set it down again.

Does the magnet suddenly snap back to its original position, or otherwise slide over your desk in search of magnetic north? You are probably (correctly) thinking this is a ridiculous experiment. It's obvious that earth's magnetic field is not strong enough to do stuff like that.

So, if the earth's magnetic field is too weak to even move a unsecured magnet that probably only weighs a few grams, you're expecting it to affect a billion tons of rock in the form of continental plates?

You can even see a complete absence of effect ib the exact same rocks you are referencing. These rocks provide evidence of past pole reversals, because different layers have different alignments.

If the polarized rock moved into alignment when the fields shifted, new layers would always be deposited with the same alignment as the old ones. The only reason these rocks are even referenced in the same breath as pole realignments is because this doesn't happen, and cannot happen.

Finally, to see how magnetic the average rock is, obtain a compass, a magnet, and a piece of gravel. Gravel is made exclusively from the least valuable (e.g. Most common) form of rock readily available, so it is a good stand in for the average composition of the earth's crust.

Find the furthest distance you can that leads the compass to point towards the magnet, rather than magnetic north. If the compass is pointing at the magnet, this means it's feild is dominating over the earth's field at that distance. Replace the compass with gravel. Does the gravel slide towards the magnet at this distance? If not, this shows that the magnetic minerals in the rock are insufficient to move it, despite being in the presence of a local magnetic field strong enough to dominate over the earth's natural field (as shown by the compass)

We routinely experience magnetic fields thousands of times stronger than the earth's own, and nothing tends to happen. The same is true of most rocks.

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Eidalac t1_jaakt3h wrote

There would need to be a critical mass of highly magnetic material in the crust, and it would have to be highly polarized and the flip would have to happen extremely fast to have any impact on the crust at scale.

Most highly magnetic material is in the core (iron) while the crust is mostly silicates which don't care about the field all that much.

The stuff that is magnetic wouldn't be polarized enough to prefer one pole to the other. There would be equal "north" and "south " pull.

Lastly the flip is thought to take around 2-12k years, with the magnetic field flickering and changing over that time

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Low-Restaurant3504 t1_ja9tpd8 wrote

That's not how any of that works, at all... like, I don't mean to be rude, but seriously, no. That's an idea even Roland Emmerich would pass on.

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