Scientists Say Earth May Escape Being Swallowed by the Sun

A new study suggests Earth may not be consumed when the Sun reaches the end of its life in about 5 billion years. For years, the prevailing view was that the Sun would expand into a red giant, engulf Mercury, Venus and probably Earth as well. The new work, by researchers at the University of Leuven in Belgium and CEA Paris-Saclay in France, argues that the Sun will also lose a huge amount of mass as it ages, weakening its gravity and possibly allowing Earth to move into a wider orbit.

Lead researcher Mats Eslinders said Earth’s fate depends on a cosmic tug of war. As the Sun swells, it will tend to pull the planet inward, but if its mass loss is strong enough, Earth could drift outward and survive the expansion. The researchers say Mercury and Venus are still expected to be swallowed because they are too close to the Sun. Mars, they conclude, should survive, and Earth may now join it.

Even if Earth avoids being engulfed, life on it is not expected to last. As the Sun becomes hotter and brighter, the oceans would evaporate, the atmosphere would change, and conditions would become too extreme for life as we know it long before the Sun dies. After the red giant phase, the Sun is expected to shrink into a white dwarf, leaving Earth, if it still exists, as a cold, dark and lifeless world orbiting a cooling star.

The scientists stress that the result is not certain because the amount of mass the Sun will lose is still hard to predict precisely. To improve their estimates, they examined the nearby star L2 Puppis, described as an older cousin of the Sun, to better understand what may happen in the distant future.