A study of how climate conditions have affected the origin and evolution of life on Earth could provide clues to understanding how climates on alien planets might affect their potential for life. The Sun used to shine less brightly when the Earth was young, so the early Earth should have been cooler than it is today. Greenhouse gases may have played an important role in warming the planet to a point where it was habitable for life. The study was recently published in the journal Astrobiology.