Did Jupiter Knock a Planet Out of the Solar System?

posted: 11/06/15
by: Discovery.com Staff
Angry Jupiter
thinkstock/edit by Danny Clemens

Once upon a time, there may have been a fifth gas planet in our solar system -- that is, until Jupiter had its say.

University of Toronto astrophysicists now believe that a "close encounter" with the Gas Giant knocked an unsuspecting planet straight out of our solar system four billion years ago.

The notion that a long-lost planet was kicked out of the solar system was first presented in 2011, but scientists weren't quite sure exactly why the ejection took place; many leading theories pegged either Saturn or Jupiter as the planet ejector.

Related: Jupiter Played a Major Role in Shaping the Solar System, Research Suggests

In a new study published in the November 1 issue of The Astrophysical Journal, UT researchers examined the orbits of Callisto and lapetus, regular moons of Jupiter and Saturn, to figure out how a planetary ejection event would have impacted each of the satellites' current orbit.

"Ultimately, we found that Jupiter is capable of ejecting the fifth giant planet while retaining a moon with the orbit of Callisto," Ryan Cloutier, study lead author and UT a graduate fellow, explains in a news release.

"On the other hand, it would have been very difficult for Saturn to do so because Iapetus would have been excessively unsettled, resulting in an orbit that is difficult to reconcile with its current trajectory."

Lesson learned: Don't mess with Jupiter.

Related: NASA Investigating the Idea of Sending 'Windbot' to Jupiter


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