Have you ever looked at the moon and noticed the plethora of surface craters and wondered why Earth has been able to withstand the same pounding from a mass amount of asteroids over millions of years? Composed primarily of nitrogen and some oxygen, Earth’s atmosphere is tasked with primarily protecting life on Earth from solar radiation. However, the Earth’s atmosphere also acts as a natural defense shield against possible asteroids that might be headed towards Earth’s surface. It’s not that Earth hasn’t seen asteroid collision before. Take for example the extinction theory of the dinosaurs or the impressive Meteor Crater in Arizona, estimated to be nearly 50,000 years old.
Also, natural erosion, volcanic activity, and other geological processes the moon doesn’t have contributed to making Earth’s asteroid impact scars much less visible. The fact remains that Earth’s atmosphere has been there to protect against asteroid collision in most in most cases. For example, many smaller objects will burn up upon entry into Earth’s atmosphere due to the atmosphere’s existence. However, for the large asteroids that are theorized to have lead to the extinction of the dinosaurs, unfortunately for them, the atmospheric protection wasn’t enough.