 The extinction of the dinosaurs at the end of the Cretaceous period is generally thought to have been caused by the Cretaceous – Paleogene impact event , which created the Chicxulub crater , demonstrating that impacts are a serious threat to life on Earth . Astronomers have speculated that without Jupiter to mop up potential impactors , extinction events might have been more frequent on Earth , and complex life might not have been able to develop . This is part of the argument used in the Rare Earth hypothesis . 
