Impact events appear to have had a major effect on the how the Solar System has changed since it was formed. Major impact events have also shaped the history of the Earth, including the evolution of life. It is thought that the Chicxulub impact, which happened 66 million years ago, caused the Cretaceous–Paleogene extinction event. There is debate over whether impacts caused any of the other extinction events throughout history. A giant impact event is thought to have produced the Moon.