Jupiter may have kicked a giant planet out of our solar system

Our solar system has four giant planets—Jupiter, Saturn, Uranus and Neptune—but at some point, we may have had five of them, according to a study published in The Astrophysical Journal.

The study points out that many models of the evolution of the solar system include a possible fifth giant planet made of ice which could’ve been “ejected” out of our system by a gas giant planet when the solar system was still unstable.

The scientists involved in the study decided to investigate the likelihood that it was either Jupiter or Saturn that  kicked out the hypothesized ice giant by looking at the current orbits of Callisto and Iapetus, moon that orbit Jupiter and Saturn, respectively.

“Our evidence points to Jupiter,” said Ryan Cloutier, a PhD candidate at the University of Toronto’s Department of Astronomy & Astrophysics and lead author of the study. The idea that there may have been a fifth giant planet was first proposed in 2011.

“Ultimately, we found that Jupiter is capable of ejecting the fifth giant planet while retaining a moon with the orbit of Callisto,” Cloutier said. “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.” — Bea Montenegro/TJD, GMA News