Early Earth's regulatory carbon/seafloor weathering process would occur on any rocky planet with water. “There’s nothing special about these processes,” says Joshua Krissansen-Totton from the University of Washington's astrobiology program and Virtual Planetary Laboratory. "We know pre-solar nebulae contained the ingredients for life; we also know countless exoplanets with those ingredients exist in habitable zones. The study widens the window of time on which life could have emerged on those planets."
The model doesn’t resolve debates about exactly when or where life emerged, but it steers scientists in productive directions for further research. For example, “if you believe life on Earth started at high temperatures, that could still be true,” Krissansen-Totton told Astrobiology Magazine, “but that would restrict origins to locally warm environs like hydrothermal vents.”
The study also has implications for planetary evolution. Boston University Earth and Environment professor Andrew Kurtz, who was not part of the study, points out that “Mars once had most of what Earth has going for it, or so we think: water on the surface, carbon dioxide in the atmosphere, and silicate rocks,” which seem to support the possibility of life having once existed there. Scientists believe Mars’ atmosphere was vented into space via solar winds, but questions remain as to what upset the Red Planet’s cyclical balance, as well as whether other planets could experience such drastic conditional changes.
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