Astrophysicists from the University of Toronto are speculating that at some point in the distant past, there was another planet in the Solar System that was similar to Jupiter, Saturn, Uranus and Neptune, in that it was a giant gas planet, and that it was forced out of the system by big brother Jupiter.

According to an article on eurekalert.org, the theory of another giant planet was first proposed back in 2011, and scientists then thought it may have been forced out by Saturn.

Ryan Cloutier, a PhD candidate in the University’s Department of Astronomy ans Astrophysics, who is also the lead author on the new study published in The Astrophysical Journal, said “Our evidence points to Jupiter.  Ultimately, we found that Jupiter is capable of ejecting the fifth giant planet while retaining a moon with the orbit of Callisto.”  Callisto is a moon currently orbiting around the the giant planet

Cloutier and his colleagues think they can rule Saturn out as the one that knocked the other planet aside, based on their analysis of the orbit of Saturn’s moon, Iapetus.

“On the other hand, it would have been very difficult for Saturn to [expel the planet] because Iapetus would have been excessively unsettled, resulting in an orbit that is difficult to reconcile with its current trajectory,” added Cloutier.

The researchers developed computer models and simulations based on the current orbiting positions of the moons around Jupiter and Saturn to examine the theory.  They explored the scenarios of the possibility of the host planet ejecting the hypothetical planet, and the disturbance the incident would have caused the orbit trajectories of each planet’s moons.

They concluded the most likely possibility would be that Jupiter was the culprit rather than Saturn, as originally suspected.

So what happened to the giant planet that was ousted?  According to natureworldreport.com, the planet is now deemed an “orphan planet”, without a star with which to orbit, and is located some 100 light years away from Earth.

The orphan has been given a name by astronomers though, even if it is kind of hard to remember.  Planet CFBDSIR2149 is believed to be roughly four-to seven-times as large as Earth, and the researchers say it was expelled from the Solar System about four billion years ago.