A team of scientists has proposed a groundbreaking theory suggesting that a massive interstellar object—potentially eight times the size of Jupiter—may have dramatically impacted the orbits of planets in our Solar System. The interstellar visitor, which passed close to the orbit of Mars, might have altered the trajectories of Jupiter, Saturn, Uranus, and Neptune. This theory, currently available on the arXiv preprint database but not yet peer-reviewed, could change how we view the Solar System dynamics and the influence of interstellar objects.

For years, astronomers have observed discrepancies between the ideal, concentric arrangement of planetary orbits and their actual three-dimensional orientations. To investigate this, the research team hypothesized that about four billion years ago, an interstellar visitor entered our Solar System. They conducted 50,000 simulations over 20 million years, varying the interstellar object’s mass, velocity, and proximity to the Sun.

The findings indicated that in about 1% of the scenarios, the gravitational influence of this interstellar object could explain the current planetary orbit changes in our Solar System. According to the simulations, the interstellar visitor may have passed within 1.69 astronomical units (AU) of the Sun—just beyond Mars’ present orbit—potentially altering the planetary orbits of Jupiter, Saturn, Uranus, and Neptune.

While previous theories suggested that the irregularities in planetary orbits were due to interactions among the planets themselves, this new study proposes that a one-time interstellar visitor event could provide a more plausible explanation. Scientists believe that such an event could explain the changes in Solar System planetary orbits, including the moderate eccentricities and inclinations observed today. The team also called for further scientific findings on the potential effects of this interstellar visitor on minor planets in the asteroid belt and the trans-Neptunian region.

“There is about a 1-in-100 chance that a flyby of this kind could produce the dynamical architecture we observe in the solar system today,” the researchers noted. Astronomers are now investigating the long-term effects of interstellar visitor planetary orbit changes, seeking to understand how interstellar objects can influence Solar System dynamics.

This Solar System interstellar visitor discovery opens up new avenues for research into the impacts of interstellar objects on planetary systems and could reshape our understanding of planetary formation and evolution.