Planets without plate tectonics can still produce enough heat, for an extended period of time, in order to sustain life. Image credit: NASA
There may be more habitable planets in the universe than we previously thought, according to Penn State (Pennsylvania State University, United States) geoscientists, who suggest that plate tectonics — long assumed to be a requirement for suitable conditions for life — are in fact not necessary.
When searching for habitable planets or life on other planets, scientists look for biosignatures of atmospheric carbon dioxide. On Earth, atmospheric carbon dioxide increases surface heat through the greenhouse effect. Carbon also cycles to the subsurface and back to the atmosphere through natural processes.
“Volcanism releases gases into the atmosphere, and then through weathering, carbon dioxide is pulled from the atmosphere and sequestered into surface rocks and sediment,” says Bradford Foley, assistant professor of geosciences. “Balancing those two processes keeps carbon dioxide at a certain level in the atmosphere, which is really important for whether the climate stays temperate and suitable for life.”
Most of Earth’s volcanoes are found at the border of tectonic plates, which is one reason scientists believed they were necessary for life. Subduction, in which one plate ...