We live on Earth's crust, but there are other layers beneath the crust. They are the mantle and the outer and inner core. In 1915, scientist Alfred Wegener said that about 200 million years ago, Earth once had a single landmass. Hot, molten magma under the surface of the crust pushed the plates apart at a crack in Earth's crust and, eventually, the landmass was split apart and continents were formed. Wegener's work led to the study of plate tectonics.
Alfred Wegener studied astronomy and meteorologyâ€”and was even a record-holding balloonistâ€”before he became famous for his theories on how the land and seas on Earth were formed and change. These ideas are continental drift and plate tectonics. Seeing that the continents fit together like a puzzle, Wegener proved the theory that all of Earth's continents were once connected. Although his theories weren't accepted until after his death, scientists use plate tectonics to explain volcanoes and many other changes on Earth.
Earth is made up of atmosphere that protects us from the sun and contains our air supply. The next part is the hydrosphere, which is all the water on the planet. The third is the geosphere, the rocks. All three parts are closely connected. If we do not take care of one part of Earth, such as the ocean, we hurt the entire planet. Scientists all over the world are working to find ways to reduce pollution and make our Earth healthier.
Take an in depth look at earth science in this science encyclopedia.