Did a Rogue Planet Reshape Our Solar System?

Researchers have discovered that a close encounter with a rogue planet or brown dwarf during the Sun’s early years could have triggered the reshuffling of our Solar System’s giant planets. Running 3000 simulations of stellar flybys, the team found that substellar objects passing within 20 astronomical units of the young Sun could destabilise the planets’ orbits just enough to match their current configuration without destroying the delicate Kuiper belt. This flyby scenario represents a new possible explanation for one of the Solar System’s defining events, with roughly a 1-5 percent probability depending on how common free floating planets actually are in young star clusters.