Recent studies indicate that gravitational influences from an external object may have significantly altered the orbits of planets in our Solar System. This research, conducted by astrophysicists from the University of Toronto and the University of Arizona, was published on a preprint server at Cornell University.
The Solar System, existing for approximately 4.6 billion years, exhibits planetary orbits that are not aligned in a single plane, suggesting a dynamic past. The study highlights that planets initially formed in perfectly circular orbits aligned with the solar equator, but external factors have since disrupted this arrangement.
Traditionally, the dynamics of planetary movement have been attributed to internal processes, with the widely accepted Nice model explaining the gravitational interactions within the system. However, the authors argue that existing models fail to fully account for the current configuration of the Solar System.
Previous theories proposed that a nearby star's gravitational field could have destabilized the system. The new research explores the possibility of a massive object, such as a planet or brown dwarf, passing through the Solar System. Brown dwarfs are substellar objects with masses between 13 and 80 times that of Jupiter.
Simulations suggest that an object with a mass between two and 50 times that of Jupiter could have approached the Sun on a hyperbolic trajectory, coming within 20 astronomical units (AU). For context, Uranus is currently about 19 AU from the Sun.
The most likely scenario involves a planet with a mass approximately eight times that of Jupiter passing as close as 1.69 AU from the Sun, slightly farther than Mars' current position. This hypothesis gains credibility from recent discoveries, including the interstellar asteroid 'Oumuamua' and comet Borisov, as well as the identification of orphan planets not gravitationally bound to any star.