
Illustration of an exoplanet in the early universe
Darryl Fonseka / Alamy
Conditions in the early universe may have allowed rocky planets with water to form much earlier than expected, possibly allowing life to begin earlier.
Astrophysicists studying the early universe believe that planet formation did not begin in earnest until the supernova released heavy elements to form planetesimals, the rocky blocks of planets around stars. Our sun and its planets formed when the universe was about 9 billion years old, and is the oldest known planet A billion years in the life of the universe.