Comet Shoemaker–Levy 9 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. In 2009, it was shown that the presence of a smaller planet at Jupiter's position in the Solar System might increase the impact rate of comets on
Erich Meyer Erich Meyer Erich Meyer (born August 6, 1951) is an Austrian engineer, amateur astronomer and discoverer of asteroids. Between 1996 and 1999, using the private observatory Meyer/Obermair in Davidschlag (municipality Kirchschlag bei Linz, Austria), he discovered a total of 21 asteroids. Seven of these asteroids were discovered together with his colleague Erwin Obermair and one together with Herbert Raab. Furthermore, he was involved in six other discoveries of asteroids between 1996 and 2005, which were assigned as site discoveries to the observatory Davidschlag by the International Astronomical Union. Meyer's most important observations include precisie astrometry of the comet Shoemaker–Levy 9,