Jupiter Doesn't Shield Earth From Comet Impacts: Study

Not only is the "Jupiter as shield" concept not true but perhaps Jupiter's most important role in fostering the development of life on Earth was just the opposite - delivering the volatile materials from the outer Solar System needed for life to form, the researchers said.

In the study published in the journal Astrobiology, Kevin Grazier from Nasa Jet Propulsion Laboratory in Pasadena, California, simulated the evolution of tens of thousands of particles in the gaps between the jovian planets - Jupiter, Saturn, Uranus, and Neptune - for up to 100 million years.

Based on the results, Grazier concluded that the widely reported shield role attributed to Jupiter is incorrect.

The study showed that Jupiter teams with Saturn to kick a significant fraction of the particles into the inner Solar System and into orbits that cross Earth's path.

He proposes that a Solar System with one or more planets similar to Jupiter located beyond the region of potential terrestrial planets is beneficial for the development of life.

"In an unprecedented effort to solve the riddle as to whether Jovian bodies shield habitable planets from impacts catastrophic to life, Dr. Grazier presents a modelling study that speaks to the incredible complexity of planetisimal evolution in the Solar System."

"In this paper, we learn that the overly simplistic 'Jupiter as shield' concept is a thing of the past, and future research in this area will require the continued use of the kinds of robust simulation strategies so effectively employed in Dr. Grazier's work," Sherry Cady, editor-in-chief of Astrobiology, said.