ONE day, 5 billion years hence, our world will come to an end. By then, astrophysicists tell us, the sun will have exhausted the supply of hydrogen in its core and expanded to become a red giant, engulfing Earth. Our planet will simply evaporate away.
Or perhaps not. We might share the fate of a planet that has just been found orbiting a star already past its red-giant phase (Nature, vol 449, p 189). It has survived encroachment by its parent star, V 391 Pegasi, yet it is not much further out than Earth is from the sun.
Is…
