As if it were a cosmic chess game, a team of astrophysicists from the University of Toronto (USA) has discovered that a close encounter with the planet Jupiter some 4,000 million years ago could have resulted in the expulsion of another giant planet (the fifth) in our solar system. The study has been published in The Astrophysical Journal .
For years scientists have theorized about the existence of this fifth giant planet along with Jupiter, Saturn, Uranus and Neptune, which could have been ejected by Saturn or by Jupiter as a result of a planetary encounter in which one of them is freed from the gravitational pull of its star . Now, new evidence suggests that Jupiter was responsible for this event.
To reach this conclusion, the astrophysicists studied the moons of these two gas giants as well as their moons, generating computer simulations based on the current trajectories of Callisto and Iapetus, satellites in regular orbit around Jupiter and Saturn, respectively. Once the simulations were developed, they proceeded to measure the probabilities that Callisto and Iapetus would have generated their current orbit if their host planets had expelled that hypothetical fifth planet from the solar system, since this event would have considerably modified their original orbit.
The results revealed that “ Jupiter was able to expel the fifth giant planet, maintaining a moon in the orbit of Callisto . On the other hand, it would have been very difficult for Saturn to do so because Iapetus would have been excessively unstable, due to an orbit that is difficult to reconcile with its current trajectory, ”explains Ryan Cloutier, lead author of the study.
