Life on other planets would likely be brief and become extinct very quickly, said astrobiologists from the Australian National University (ANU). In research aiming to understand how life might develop, scientists realized new life would commonly die out due to runaway heating or cooling on their fledgling planets. About four billion years ago, Earth, Venus, and Mars may have all been habitable. However, a billion years or so after formation, Venus turned into a hothouse and Mars froze into an icebox.