Is It True That Jupiter Protects Earth?

Is it true that Jupiter could be considered our friendliest planet because - without Jupiter - comets would be more likely to hit us? The answer is yes... and no. Some astronomers believe that one reason Earth is habitable is that the gravity of Jupiter does help protect us from some comets.
Long-period comets, in particular, enter the solar system from its outer reaches. Jupiter's gravity is thought to sling most of these fast-moving ice balls out of the solar system before they can get close to Earth.