the below question on the north pole

[3 blind mice]

in the question somebody suggested that the face of the earth has moved like clouds in the sky over time?

how could this happen when i presume all of the land is fixed with a sea in between them?

i know land has moved but my question is......how??

[fo3nix]

the top layer of the Earth is made from a series (7 i think, but may be wrong) of plates, that are mostly fixed, but can move slightly. the areas where the plates meet is where earthquakes occur, as they rub together.

india is on one plate, and the top of it, round nepal, is the end of that plate. right now i believe that plate is moving north at a rate of about 1cm per year -- hence the mountain range there, with Everest, etc.

why the things move is down to pressures deep within the earth, etc.

[heathfield]

I like your analogy to clouds in the sky - lovely! As to how those tectonic plates move, there's a pretty good explanation here

[jake-the-peg]

Glad you liked it.

If you look at a map you'll notice that Africa and America look strangely as if they'd fit neatly together. People started noticing this sometime in the Elizabethan period when maps started to get good enough for this to become aparent.

Ever since then the idea that the continents were once joined was in and out - but nobody had a mechanism. In 1912 Alfred Wegner showed that on either side of the Atlantic where Europe and America would have touched the fosils you find matched as well as the coastline!

[jake-the-peg]

In 1929 just as everybody had had enough of Wegners ideas about gravity causing the continents to spread in stepped Arthur Holmes - He correctly worked out that the continents and sea floor sit on top of convection currents deep in the earth. These currents are so huge as to force the continents apart little by little.

There's the so called mid atlantic ridge where as they push apart new seabed is formed by molten magma, and when you get a big push there are often undersea earthquakes like the one that caused the Tsumai 18 months ago.

[jake-the-peg]

As fo3nix says it's as little as 1 cm a year but that's 1 meter every 100 years or 1 Km every 100,000 years, 60 million years ago when dinosaurs were about is 600 Km - and the Earth is 8 times as old as that!

On geological time scales the continents fairly motor!