Distant future of the Sun and Earth revisited
Level 5 - mechanism / opinion, no new human data
Level 5 by design analogy, not clinical CEBM (computational astrophysical modeling and theoretical simulation).
OpenAlex W3099060193 · doi:10.48550/arxiv.0801.4031
What was done
The authors computed stellar evolution models using a calibrated cool-wind mass-loss formula to simulate the distant future of the Sun and the solar system. For each time-step during the red giant phases, the model evaluated solar mass loss, Earth's resulting orbital expansion, and counteracting orbital angular momentum losses from tidal interactions and dynamical drag in the lower solar chromosphere.
What was found
The Sun is modeled to lose 0.332 solar masses by the tip-RGB phase (7.59 billion years from now). Tidal interaction and chromospheric drag overcome orbital expansion, resulting in Earth's engulfment during the tip-RGB phase. Planetary survival would require a present-day minimum orbital radius of approximately 1.15 AU. Due to heavy RGB mass loss, the subsequent tip-AGB giant will not exceed its tip-RGB size or drive a standard planetary nebula, producing at most a small circumstellar shell of a few hundredths of a solar mass.
Why it matters
This work provides an updated astrophysical model for the ultimate fate of the solar system, demonstrating that tidal dissipation counteracts mass-loss expansion to cause Earth's engulfment.
Limits
The findings depend entirely on theoretical evolutionary codes, parameterized mass-loss formulations, and simplified models of tidal coupling and chromospheric drag, none of which can be empirically observed for the future Sun.
Cited by
- context The Earth has approximately four billion years of lifespan remaining.