Overview
- A peer‑reviewed paper published in Astronomy & Astrophysics in June 2026 reports that modern simulations can place Earth outside the Sun’s maximum radius during the red‑giant and asymptotic giant branch phases.
- The result depends on a tug‑of‑war between two processes: tidal forces from the swollen Sun that pull planets inward and stellar mass loss that weakens the Sun’s gravity and lets orbits expand.
- Researchers used updated tidal‑dissipation prescriptions developed over the past 15 years that predict weaker tidal braking in giant stars, which reduces the inward pull on Earth.
- The team constrained late‑stage solar mass loss using observations of the evolved star L2 Puppis and found that, when combined with the revised tides, Earth and Mars can escape in some models while Mercury and Venus remain doomed.
- The conclusion is conditional and far in the future—on the order of five billion years—and it does not imply continued habitability, so authors call for more observations and improved models to narrow the remaining uncertainty.