Revise GCSE Physics


Question:Why does the surface of the Earth not look similar to the surface of the Moon?

The Earth is bigger than the Moon so actually it must have been hit by more asteroids over its history that the Moon has and craters must have been created. The Earth has 30-60 tonnes of rock fall to Earth every year, so craters are produced regularly.

There are three reasons why the Earth does not have a similar appearance to the Moon.

1.Firstly, the atmosphere reduces the severity of asteroid collisions by helping to burn up the asteroid. Any object entering the atmosphere at high speed experiences extreme heating due to frictional forces between the object and the gas particles of the atmosphere. Much of a small asteroid's mass can be lost before it collides with the Surface.

2.Secondly, the Earth's surface is covered by oceans and vegetation which obscure the appearance of the craters that were produced in the past.

3.Lastly, the craters are removed over time by weathering by the atmosphere; the oceans and plant and animal life cause the craters appearance to be changed over time by eroding the edges away. Weathering tends to make everything flatter over time.

On the Moon there is no atmosphere or plant life to either cover or erode the craters so impact craters remain unchanged.