The earth is about 4.6 billion years old. When we look at our world, we see that there are seven main land groups or continents: Africa, Antarctica, Australia, Europe and Asia and North and South America. But the world didn’t always look the way it looks today. In the beginning, the earth was very, very hot. It was covered with magma, or liquid rock. It took many years for it to cool down. Slowly, as it cooled off, part of the earth became water and part of it became rock and mountain. Most of the earth was covered with water. Some scientists believe that the earth was 80% water in the beginning. There was only one big piece of land. This is called “Pangea” or the supercontinent. The first dinosaurs were able to walk all over this supercontinent.
But the inside of the earth isn’t solid rock. Most of the inside of the earth is still a very, very hot liquid magma. This magma doesn’t stay still. It moves a lot and sometimes shoots through the surface from volcanoes. It sometimes moves the plates of land apart or jams them together to form mountains. About 180 million years ago, magma helped to break the supercontinent Pangea into two main sections. The northern part of the supercontinent was called “Laurasia”. It would later become North America, Greenland and Eurasia. The southern part was called “Gondwanaland”. It would later become Antarctica, Africa, South America, Australia and India. The dinosaurs that were on Laurasia could not walk to Gondwanaland, and they began to change in their new environment.
India began moving north. It traveled a long way to reach the Asian continent. India moved four inches per year over 135 million years. That’s very fast for a big piece of land! When it reached the Asian continent, it crashed into it at such speed that it created the highest mountains on earth: the Himalayas. The plates are still moving today. That means that the Atlantic Ocean is getting larger and the Pacific Ocean is getting smaller. The arrows show how the continents are still moving. What will the earth look like in 1,000 years? Or one million years? Will North and South America crash into Australia? Will the Mediterranean Sea disappear? No one knows for sure, and scientists are still studying how land moves today.