Passing stars may unravel the solar system's hidden fragility
Researchers Nathan A. Kaib and Sean N. Raymond evaluated the impact of passing stars on the long-term stability of the solar system. What does the future hold for Earth?
The authors of the article "The influence of passing field stars on the solar system’s dynamical future," published in ScienceDirect, emphasize that previous studies often assumed the solar system was isolated from the rest of the galaxy. In their simulations, they took external influences into account and concluded that close flybys of stars significantly increase the probability of orbital instability.
Possible scenarios
The scientists simulated thousands of possible scenarios spanning five billion years, taking into account the current orbits of the eight planets in the solar system and Pluto. Unlike isolated models, which may underestimate future orbital changes of the giant planets by more than an order of magnitude, the new simulations indicate that our planets and Pluto may be much less stable than previously thought.
The study showed that over a five billion-year perspective:
- Pluto, which was completely stable in isolated models, has a 5% chance of destabilization due to passing stars;
- The chance of Mercury's destabilization increases by 50-80% compared to isolated simulations, which estimated the risk at about 0.8-1%;
- There is a 0.3% chance that Mars could be lost due to collision or ejection from the solar system.
Stability of our system
Earth has a 0.2% probability of being involved in a planetary collision or being ejected from orbit.
The study indicates that, although the stability of the solar system during its main life phase is very likely (it is estimated that in about five billion years, the Sun will become a red giant and destroy Earth anyway), it is not guaranteed. Passing stars become a key risk factor for our cosmic "backyard."
