Is the switching of the poles gonna be drastic and sudden or gradual? And, when it happens, what will happen?

Answer 1

Very sudden. At precisely 4:15pm Sun 10/14/07. Oh no,wait. That's the Pats/Cowboys game.

Seriously? It's probably happening now. Remember time is relative. If it happens over thousands of years is that sudden, or astronomicly speaking, slow?

The effects are really unpredictable. Just theories based on hypothesies. Take your pick because there's several to chose from.

Answer 2

On the astronomical scale, the switching will be instantaneous. However, compared to a human lifetime, it will be gradual.

When the reversal of magnetic polarity was discovered last century, researchers found overlaid layers of rock showing one magnetic orientation or the other, with nothing in between. Of course, these layers were deposited at various intervals and it was difficult to judge how fast the switch took.

Still, it was supposed that Earth's magnetism decreased to zero, then started again, but with the reverse orientation. This is how the magnetic polarity switches on the Sun every 11 years. It was also supposed that this reversal was rather quick (at least, on geological scale).

Recently, we are more inclined to think that there is no real switching. Rather, the magnetic poles 'migrate' from one polar region to the other over a period of a few centuries.

We have spent almost a million years with the Earth's magnetic poles in (relatively) stable positions near the poles of rotation. They are now moving 'rapidly' and may be spreading or splitting (the magnetic pole in Antarctica is already split).

We will continue to have a magnetic field, it will just be more difficult to understand and predict. Magnetic compasses may become less useful and predictable, because they may point to directions that have nothing to do with our usual (and useful) navigation coordinates.

But Earth will continue to have a magnetic field, protecting us from cosmic rays and solar wind (high energy charged particles).

When I did some research into this (I was writing a book on magnetism a long time ago), it was already thought that the reversal had started and would take up to five centuries. It now looks like it might be a bit faster than that (let's say two centuries instead of five), but I have not been involved in recent research.

For example, the web site given below states that some information taken from rocks deposited during transition periods show that reversals "take roughly 5,000 years, with estimates ranging from 1,000 years and 8,000 years."

It also describes some of the things one could expect during that 'short' time.