How often does a comet/asteroid collide with Earth?
According to David Levy, a half-mile-wide object should hit the Earth on the average of once every 100,000 years. However, small objects the size of a grain of sand or a piece of gravel hit the Earth each minute. The frequency of a 100-m asteroid/comet hitting Earth is about once every 100 years. The chances could be higher or lower because these small objects are not easy to see with our telescopes, so their number is not well known. 20.* How are solar system objects affected by gravity-induced impacts? The craters on the moon were caused by impacts with other objects. Craters on Earth are evidence that large objects have hit Earth. Many scientists believe that an asteroid or a comet was responsible for the extinction of the dinosaurs. The current theory of the formation of the moon is linked to a collision or close encounter with a very large body. The oceans are believed to have formed from the impacts of many water-rich planetesimals and cometesimals. An asteroid hit the sparsely p
