With high hopes for Kepler 1625b, David Kipping at Columbia University has been busy looking for moons of exoplanets (Science News, 10/14/17). He makes the case that a moon could be more livable than the planet it orbits. Or it could make that planet more habitable, creating life-enhancing tides like ours.
Given the surprising diversity of Pluto’s geology, we now know that smaller planets and moons can have “striking diversity of geologic features.” Even Pluto’s moon Charon has deep features and vast ice plains. Enceladus and Europa, with their leaks and sub-ice oceans, are
prime suspects in the search for exolife. But the most exciting new evidence for hospitable planet geology is the report from NASA/JPS-Caltech/SETI Institute on December 4 stating that subduction may be happening on Europa.
i.e. Europa may have “plate tectonics similar to those on Earth.” (See Journalof Geophysical Research; Planets.) There is evidence of extension and spreading of the surface ice that could provide “…oxidants and other food for life…” to the ocean below. There is “…geological evidence for ocean water upwelling…and cryovolcanism…” and “…surface spraying of
salty subice ocean water.”
Why is plate tectonics so important in getting life going? In their book Rare Earth, published in 2000, Ward and Brownlee devote a chapter to the important role plate tectonics may have played on Earth. New studies of Earth’s heavy and light plates may help us understand when
plate tectonics began to push continents. Plate tectonics may have been episodic before it became continuous, as it is now; its origins here are not well understood.
An article in Scientific American December 2017 by Shannon Hall, “Dawn of Plate Tectonics,” suggests that shifting crustal plates on Earth—and perhaps now on Europa—dig out ocean basins and push mountain ranges up, while “…altering the composition of the atmosphere and oceans…[possibly affecting] the supply of nutrients…” to any emerging life.
In Rare Earth, Ward and Brownlee suggest that plate tectonics also “…promotes high levels of biodiversity….” By recycling minerals and changing sea levels, it keeps carbon dioxide tamed so that Earth’s temperatures provide liquid water. Plate tectonics also makes possible Earth’s magnetic field and produces changing continents—i.e. all the necessities of life we enjoy here. Hence its importance in the search for life on exoplanets.
Author of The Archives of Varok
The View Beyond Earth (Book 1.)
The Webs of Varok (Book 2.)
Nautilus Silver Award 2013 YA
ForeWord IBPA finalist 2012 adult SF
The Alien Effect (Book 3.)
An Alien’s Quest (Book 4. Released Nov.21, 2016)
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Reviews of significant books- http://www.goodreads.com/Cary_Neeper
How the Hen House Turns- http://www.ladailypost.com
Complexity, Bio, Bibliography and Links- http://caryneeper.com
Astrobiology- http://astronaut.com search:Who’s Out There