10 Biggest Unsolved Mysteries In Science

9. How Do Plate Tectonics Work?

Bet you thought we'd got this one all figured out, right?

People used to think that the continents sort of drifted about the ocean, occasionally crashing into each other and raising a mountain range. Then, this theory was transformed into plate tectonics, with massive sections of the Earth's crust moving about on a subterranean ocean of magma.

So far, so GCSE Geography.

HOwever, the main sticking point is that we don't actually know what causes this movement. It was generally thought until quite recently that they were drifting on some kind of convection current in the Earth's mantle, but so far none of our models based on these theories can predict or match tectonic movement to a satisfactory level.