Crater formation occurs when an object, such as a meteorite or asteroid, collides with a planetary surface. The impact generates a shock wave that excavates a bowl-shaped depression, known as a crater. The size and depth of the crater depend on the speed and size of the impacting object. Crater formation can also happen through volcanic activity. In this case, a volcano erupts, causing the ground to collapse into a void left by the expelled magma. This results in a different type of crater, often referred to as a caldera, which can be much larger than impact craters.