Planetary instability refers to the dynamic and often unpredictable changes in the structure and behavior of a planet or planetary system over time. This can encompass a range of phenomena, including orbital changes, atmospheric disturbances, geological activity, or shifts in climate. In the context of celestial mechanics, a planet may exhibit instability if its orbit becomes eccentric, leading to variations in distance from its star, which can affect temperature and weather patterns. In a broader sense, planetary instability might also refer to a planet’s potential to undergo significant changes due to internal processes (such as volcanic eruptions or tectonic activity) or external influences (like gravitational interactions with other celestial bodies). The study of planetary instability is crucial in understanding the evolution of planets, their potential habitability, and the characteristics of exoplanets in distant solar systems.
Scientific detective work has led to the conclusion that the "great instability" event, which caused chaos among the planets in our solar system, occurred between 60 and 100 million years…