if magnetic poles shift,how would we know where north is?physical poles stays the same,but compasses wont work?

We can always find true north by observing the motion of distant star images in the sky across the night.

They will all form concentric circles, and where the circles are of least radius, those are stars at the celestial north and south poles.

Polaris is interesting, because all the other stars form concentric circles around it...and it seems to remain in place, as far as the extent of your lifetime is concerned.

You can always use the "north star", or the smallest of the concentric circles to locate the direction of true north...look at it, and then drop to the horizon, and you see which way is true north.

In fact, did you know that humans figured how to use the stars to find true north LONG before the invention of the compass?

The last time there was a magnetic reversal was 780,000 years ago.

The last time there was a "magnetic excursion" (a wandering of the poles, but without a polarity reversal) was 41,000 years ago.

Each time there is such an event, the field strength resets to 10 (in the units we use to measure the magnetic moment of the field). The next event begins when the field strength has dropped to 4 (not zero).

It is presently between 7 and 7.5 units, so we still have at least three to five thousand years before the next event (the drop goes faster as the value goes down).

Once an event begins (a full reversal or just an excursion), it takes about 5,000 years to happen.

People have stopped using magnetic compasses almost 20 years ago. Ships and planes have been using gyro-compasses for almost 50 years, and GPS for at least 10 years.

The Earth's magnetic poles move about 40 miles per year. Compasses still "work" exactly the same way they always have. They'll point toward the north (or south) magnetic pole. As long as you know where the magnetic poles are, you can still use compasses for navigation, no matter how much they move.

get a small scale map. At the top you will see a set of marks showing magnetic North and the direction of drift and the drift rate when it was printed.

If you use a map and compass you need to know the offset between Geographical North and Magnetic North.

Eventually a reversal episode will happen. We have never witnessed this and do not KNOW what happens. Field collapse or many local fields - compasses will certainly be of little use until the new reversed field establishes.

The geographic pole is the axis around which the Earth rotates in area. The magnetic pole is the place the strains of force of the Earth's magnetic section converge. the objective of the Earth's magnetic section isn't so nicely understood, yet is regarding action of the molten middle that involves dissimilar iron deep interior the Earth's center. it isn't almost as orderly by way of fact the rotation of the Earth as an entire. The magnetic poles wander around fairly extremely in a chaotic technique, and are pointed out to have reversed (north will become south and south will become north) many times over the existence of the planet. in comparison to that the axis of rotation is very stable and orderly, with its maximum crucial action being the 26,000 3 hundred and sixty 5 days wobble undemanding as precession, that's the area the pole slowly and consistently strikes by potential of a circle.

The earth's magnetic pole and what we know as the true north are not exactly in alignment. The difference between the true north and magnetic north is called Variation. This angular difference in degrees of Variation is used for calculating in navigation purposes for example in air travel and sea travel to keep on the right track in relation to True North.

there are several factor's that can affect the compass from pointing to true north. but the one above relates directly to the compass pointing to magnetic north. the other ones are briefly described on the link below.

I am a pilot.

Hope I helped a bit.

It is your misconception.

Nowhere in History there was a geographical or magnetic pole shift. The compass has always shown the same. Only its direction was shifted a couple of degrees one way or the other over decades, as magnetic south pole shifted on the map to places nearby in Greenland or some big island norh of Canada.

There is a theory that when some Asteroid of size comparable to Mars hit the Earth billions of Years ago Earth's Poles went askew and that is called the Pole Shift.

the north pole wanders all the time. So we re used to it moving.

As for your compass, just look at the other side of the needle for "north"

GPS.