German scientists have discovered the mechanism behind continental drift.
A team at the Friedrich-Schiller-University Jena said water could allow the silicate layer in the planet's mantle to partially melt.
The solid silicate would act as a soft bed over which the continents could move.
Previously, scientists were baffled because temperatures did not appear to be high enough to allow the silicate to melt. But the Jena team found water could be stored at the same depth as the silicate layer and the water could lower the silicate's melting point.