Earth’s stable temperature past suggests other planets could also sustain life

NASA Johnson Space Center — The study may also help shed light on what conditions were like during the early evolution of life on Earth.

New research from the University of Washington suggests a milder youth for our planet than what has often been cited. An analysis of temperature through early Earth’s history, published the week of April 2 in the Proceedings of the National Academy of Sciences, supports more moderate average temperatures throughout the billions of years when life slowly emerged on Earth.

“Ideas about the early Earth’s environment are all over the place, from a very hot world, to one locked in a permanent ice age, from a world with acidic oceans to one with seawater so alkaline it would sting your eyes,” said David Catling, a UW professor of Earth and space sciences. “These simulations show that our early world had about the same average temperature as today, and a seawater pH within roughly one unit of neutral.”

That is good news for the search for life on other planets. If Earth’s temperature was moderate throughout its history, other planets located in the habitable zone must also retain a fairly stable climate long enough for other lifeforms to evolve.