section_path: Interaction with the Solar System/Impacts
section_name: Impacts
paragraph_text: Impacts
  
  Jupiter has been called the Solar System's vacuum cleaner because of its immense gravity well and location near the inner Solar System. There are more impacts on Jupiter, such as comets, than on any other planet in the Solar System. For example, Jupiter experiences about 200 times more asteroid and comet impacts than Earth. In the past, scientists believed that Jupiter partially shielded the inner system from cometary bombardment. However, computer simulations in 2008 suggest that Jupiter does not cause a net decrease in the number of comets that pass through the inner Solar System, as its gravity perturbs their orbits inward roughly as often as it accretes or ejects them. This topic remains controversial among scientists, as some think it draws comets towards Earth from the Kuiper belt, while others believe that Jupiter protects Earth from the Oort cloud.
  
  In July 1994, the Comet Shoemaker–Levy 9 comet collided with Jupiter. The impacts were closely observed by observatories around the world, including the Hubble Space Telescope and Galileo spacecraft. The event was widely covered by the media.
  
  Surveys of early astronomical records and drawings produced eight examples of potential impact observations between 1664 and 1839. However, a 1997 review determined that these observations had little or no possibility of being the results of impacts. Further investigation by this team revealed a dark surface feature discovered by astronomer Giovanni Cassini in 1690 may have been an impact scar.