The jagged peaks of the Himalayas are still rising as the Indian plate moves north
AGES OF EAR TH In its 4.6-billion-year lifetime, our planet has gone through significant changes
1 HADEAN
4.6 TO 4 BILLION YEARS AGO
Hot and constantly bombarded by space rocks, including a massive impact that created the Moon, the surface of the early Earth was molten rock. But liquid water may have existed on the planet due to the high atmospheric pressure.
O ur planet didn’t always look the way it does today. And if you’ve ever looked at a globe and wondered if eastern South America would fit into the western edge of Africa, then you’re right – it did. If you wanted to walk from Nigeria to Brazil without the Atlantic Ocean in the way, however, you’d need to travel back 140 million years when weak spots in the Earth’s crust began to pull apart as the tectonic plates beneath it moved. Seawater poured into the gap, creating the immense ocean we know today, and magma from Earth’s mantle rose to the surface, making the seabed. But it took a very long time.
These plates – rigid sections of Earth’s crust that slowly move and shape the continents we know today – are in constant motion. It’s a process known as plate tectonics, and they have been moving for most of the planet’s 4.6-billion-year history. The plates drive the evolution of Earth through their motion, especially when they grind