Passing stars pose hidden threats to the solar system's stability
Researchers Nathan A. Kaib and Sean N. Raymond assessed the impact of passing stars on the long-term stability of the Solar System. What future awaits Earth?
The authors of the article, published in ScienceDirect, "The influence of passing field stars on the solar system’s dynamical future," emphasize that previous studies often assumed the Solar System was isolated. In their simulations, they accounted for external influences and concluded that close flybys of stars significantly increase the probability of orbital instability.
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 giant planets by more than an order of magnitude, new simulations show that our planets and Pluto may be significantly less stable than previously thought.
The mentioned study found that over the span of five billion years:
- Pluto, which was completely stable in isolated models, has a 5% chance of destabilization due to passing stars
- The chance of destabilizing Mercury 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 will be lost due to a collision or ejection from the Solar System;
- Earth has a 0.2% probability of being involved in a planetary collision or being ejected from its orbit.
The study indicates that although the stability of the Solar System throughout its main lifespan (it is estimated that, in about five billion years, the Sun will turn into a red giant, potentially destroying Earth) is very likely, it is not guaranteed. Passing stars become a key risk factor for our cosmic "neighbourhood."
