Earth May Survive the Dying Sun, KU Leuven Researchers Find

For decades, the prevailing scientific narrative held that Earth would be consumed by the Sun when our star exhausts its nuclear fuel in roughly five billion years. New research from KU Leuven and CEA Paris-Saclay, published in Astronomy & Astrophysics, now challenges that assumption, suggesting that our planet may instead escape engulfment and continue orbiting the Sun’s white dwarf remnant.

A Delicate Tug-of-War

The study, led by PhD researcher Mats Esseldeurs at KU Leuven’s Institute of Astronomy, reveals that Earth’s fate hinges on a delicate balance between two opposing forces. As the Sun expands into a red giant and later an asymptotic giant branch (AGB) star, its gravitational tidal forces will pull Earth inward. At the same time, the dying Sun will shed a significant fraction of its mass through powerful stellar winds, weakening its gravitational grip and allowing Earth’s orbit to drift outward.

“The fate of Earth depends on a delicate balance between these two effects,” Esseldeurs explained in a KU Leuven press release. “If tidal interactions dominate, Earth is engulfed. If mass loss dominates, Earth escapes to a wider orbit.”

Advanced Modelling Changes the Picture

What sets this study apart is its methodological sophistication. Previous research relied on simplified tidal prescriptions dating back to the 1960s, often predicting Earth’s inevitable engulfment. The new work uses ab initio (first-principles) calculations of tidal dissipation that account for the internal structure and dynamics of evolved stars — a significant advance over earlier approximations.

Using these updated models, the team found that tidal interactions are weaker than previously assumed. As a result, Earth survives both the red giant and AGB phases of the Sun. Mercury and Venus, however, are inevitably engulfed during the red giant phase.

“A better understanding of tidal physics and the most advanced constraints we have on mass loss allow us to say that — in the current state of knowledge — Earth could move away from the Sun, contrary to what was predicted before,” said co-author Stéphane Mathis of CEA Paris-Saclay.

The Great Unknown: How Much Mass Will the Sun Lose?

Despite the encouraging results, the researchers caution that significant uncertainty remains. The final outcome depends critically on how rapidly the Sun loses mass during its AGB phase — a parameter that remains poorly understood and difficult to observe.

To address this uncertainty, the team turned to L2 Puppis, a nearby evolved star with an initial mass remarkably close to the Sun’s (0.98 solar masses). Using L2 Puppis as a proxy, the observational data points toward Earth’s survival. But the margin is narrow, and different measurement methods yield mass-loss rates that differ by nearly two orders of magnitude.

“The largest uncertainty no longer comes from the tidal calculations, but from how much mass the future Sun will lose,” Esseldeurs noted. “Observations of Sun-like giant stars currently point towards Earth’s survival, but we need better observations before we can be certain.”

No Life, But the Planet May Endure

While the prospect of Earth’s survival may sound hopeful, Prof. Leen Decin of KU Leuven offered an important caveat: long before the Sun reaches its giant phases, Earth will become uninhabitable.

“That doesn’t mean Earth will remain a habitable place,” Decin said. “Long before the Sun reaches its giant phase, the temperatures on Earth will rise so drastically that life becomes impossible.”

The Sun’s increasing luminosity will boil the oceans and strip the atmosphere billions of years before the red giant phase begins. The planet itself, however, may endure as a scorched rocky world orbiting a white dwarf.

What Comes Next

The study, published in Astronomy & Astrophysics on 19 June 2026, represents a major step forward in understanding our solar system’s distant future. But the researchers emphasize that the question is far from settled.

Upcoming missions like ESA’s PLATO, expected to launch in the coming years, will detect many more planets orbiting giant stars, enabling population-wide studies of planetary survival. Combined with better observational constraints on AGB mass-loss rates, these efforts may finally resolve one of astronomy’s most profound questions: what will become of Earth when the Sun dies?

As reported by VRT NWS and The Brussels Times, the findings have captured global attention — not because they promise a future for humanity, but because they rewrite the final chapter of Earth’s story.