QUANTA MAGAZINE - Earth’s fate rests on a coin flip.
In 5 billion years, our sun will balloon into a red giant star. Whether Earth survives is an “open question,” said Melinda Soares-Furtado, an astrophysicist at the University of Wisconsin, Madison. Sure, Earth could be swallowed by the sun and destroyed. But in some scenarios, Earth escapes and is pushed further out into the solar system.
Now, a nearby planetary system has offered clues to our planet’s cosmic hereafter. About 57 light-years away, four planets orbit a sunlike star that is 10 billion years old — twice as old as the sun, and already in the advanced stages of its life. Stephen Kane, an astrophysicist specializing in planetary habitability at the University of California, Riverside, recently modeled what might happen to the elderly system’s planets when the star becomes a red giant in a billion years. He found that most of the inner planets will be engulfed, but that the outermost known planet, which has an orbit similar to Venus’, might survive.