216 research outputs found
Inevitability of Plate Tectonics on Super-Earths
The recent discovery of super-Earths (masses less or equal to 10
earth-masses) has initiated a discussion about conditions for habitable worlds.
Among these is the mode of convection, which influences a planet's thermal
evolution and surface conditions. On Earth, plate tectonics has been proposed
as a necessary condition for life. Here we show, that super-Earths will also
have plate tectonics. We demonstrate that as planetary mass increases, the
shear stress available to overcome resistance to plate motion increases while
the plate thickness decreases, thereby enhancing plate weakness. These effects
contribute favorably to the subduction of the lithosphere, an essential
component of plate tectonics. Moreover, uncertainties in achieving plate
tectonics in the one earth-mass regime disappear as mass increases:
super-Earths, even if dry, will exhibit plate tectonic behaviour.Comment: 13 pages, 2 figures and 1 table; in press in ApJ
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