You can reverse continental drift!
Back in the time of the dinosaurs, Australia was just one small part of a much bigger continent. Can you piece together the ancient supercontinent, Gondwana?
The ground under your feet might feel pretty stable, but it’s actually moving. The rocks beneath your feet float on a sea of molten magma (lava). When the magma moves, it drags the surface rocks along for the ride. This is known as continental drift.
We haven’t always known about this. Continental drift was a controversial theory for many years. Many scientists could not imagine a force strong enough to shift entire continents. But there was a lot of evidence. For example, the coastlines of South American and Africa match surprisingly well, and similar fossils are found in matching regions on the continents.
Eventually, scientists set up experiments to measure the speed of the continents. One way is to measure the distance from Earth to the Moon, by bouncing lasers off the Moon’s surface. Astronauts set up mirrored reflectors on the Moon just so we could do this!
Current measurements show that Australia is the fastest continent, moving north at about 7 centimetres per year. That adds up to 70 kilometres every million years, or a whopping 7,000 kilometres since the breakup of Gondwana, 100 million years ago.
Subscribe now!
0 comments