Earth’s rocky crust, or lithosphere, is made up of 14 massive plates that float atop the planet’s semimolten mantle and make up the major landmasses and ocean basins. Five of these tectonic plates are the progeny of one–a giant plate known as Gondwanaland, which began to break up about 140 million years ago and eventually gave rise to Africa, Antarctica, India, Australia, and South America. Most of these fragments moved away from one another at about 5 centimeters per year, taking millions of years to arrive at their present locations. But the Indian plate raced along at 20 centimeters per year and eventually slammed into southern Asia with so much force that the collision gave rise to the Himalayas, the highest mountain range on dry land.
What enabled the Indian plate to move so fast? An Indian-German team may have discovered the answer: The plate is considerably thinner than its Gondwanaland siblings.