The theory that continents move is known as plate tectonics, and it is widely accepted by the scientific community. Here are the four main pieces of evidence that support this theory:
1. Fossil evidence: Fossils of the same species have been found on multiple continents that are separated by oceans today, suggesting that the continents were once connected. For example, the Mesosaurus reptile fossils are found in both Africa and South America. This implies that these continents were once joined together before they drifted apart.
2. Paleomagnetism: The Earth has a magnetic field, and the direction of this field has changed over time. As rocks form, they record the magnetic field at the time of their formation. By studying the magnetic orientation of rocks on different continents, scientists have been able to show that the continents were once in different locations on the Earth's surface.
3. Geological evidence: The rock formations found on opposite sides of the Atlantic Ocean, such as the Appalachian Mountains in North America and the Caledonian Mountains in Europe, have strikingly similar structures and ages. This indicates that they were once part of the same mountain range, and the separation of the continents caused by tectonic movement caused the range to split.
4. Seafloor spreading: In the 1960s, scientists discovered that new oceanic crust was forming at mid-ocean ridges, where tectonic plates were pulling apart. As the new crust forms, it moves away from the ridge and eventually collides with a different tectonic plate. This process, known as seafloor spreading, provides evidence that tectonic plates are in motion and that continents are also moving as a result.