A burned-out Earth bakes in the heat of the red-giant Sun in this illustration depicting our planet's bright, hot future. The Sun is slowly expanding, which increases the energy it radiates into space. By a billion years from now, the Sun will be so bright that it will boil away Earth's oceans and atmosphere, leaving a dead planet. Billions of years later, the Sun will swell to dozens of times its current size, perhaps engulfing the remnants of Earth. [Fsgregs/Wiki]