Artist's rendering of exoplanet surface

As we search the heavens for a possible twin, we’ll have to take into account the stages of growth – infancy to maturity. A rocky planet with the beginnings of life could be shrouded in an orange haze, as Earth once might have been. Read More: Marble in the Sky: the Hunt for Another Earth


NASA/JPL-Caltech/Lizbeth B. De La Torre