Scientist and team member Charles Corfield describes the continental collision that formed Everest as “the biggest train wreck on the planet.”

A hundred million years ago a vast sea separated India from Eurasia. Then India began drifting northward at a rate of about four inches (ten centimeters) a year. In geologic time, that’s breakneck speed.

India collided with Eurasia some 50 million years ago. Land crumpled and buckled upward—the birth of the mighty Himalaya. But the tumult wasn’t over. A cataclysmic uplift 20 million years ago formed much of the present-day Himalaya. Yet they still weren’t the dramatic peaks we know today.

“About eight million years ago,” says geologist Mark Harrison, “all hell broke loose when the present range, the really steep topography, developed.” Now slicing nearly six miles (ten kilometers) into the sky, the Himalaya became the highest mountain range on Earth.

India still presses forward; indeed, the Indian subcontinent has penetrated more than 1,200 miles (1,900 kilometers) beneath Eurasia. As India pushes, Mount Everest continues to rise.

How fast is the great peak growing? In 1994 researchers placed a global positioning satellite (GPS) device on the South Col, a plateau below the summit. Readings suggest that Everest grows 0.1576 inches (about four millimeters) each year.

Other tectonic forces, however, may cost Everest some of its height. Do they and the peak’s growth cancel each other out? That’s a key question for the expedition team.