Study Says Earth May Survive Sun's Red Giant Phase in 5 Billion Years
Updated
Updated · WIRED · Jul 6
Study Says Earth May Survive Sun's Red Giant Phase in 5 Billion Years
3 articles · Updated · WIRED · Jul 6
Summary
A new Astronomy & Astrophysics study challenges the long-held view that Earth will be swallowed when the Sun becomes a red giant about 5 billion years from now.
Improved models suggest tidal dissipation would sap less orbital energy than earlier estimates, while solar mass loss could weaken the Sun's gravity enough to push Earth's orbit outward.
Observations of red giant L2 Puppis—about 209 light-years away—support the possibility that mass loss can outweigh tidal drag during this stage of stellar evolution.
The outcome is still uncertain because stellar winds and late-stage thermal pulses remain hard to predict; if the Sun sheds less mass, tidal forces could still pull Earth inward.
Even under the more optimistic scenario, Earth is expected to become uninhabitable within roughly 2 billion years, while Mercury and Venus are projected to be engulfed.