I've said this before in this space, but the Earth is weird. Consider this:
The distribution of elevation across multiple planets and moons in our solar system. Credit: Vita-Finzi and Fortes, 2013.
Vita-Finzi and Fortes, 2013.
These plots show the distribution of surface elevations on a bunch of large and small bodies in our solar system. Something should jump out pretty quickly: All have a single peak for elevation except for Earth and Mars. That's weird! Why would any planet have two different peaks for the distribution of elevation?
For Earth, the explanation is relatively straight forward: we have two types of crust. Oceanic crust that underlies the oceans is thin, dense and low in silica (silicon oxide) while continental crust is thick, buoyant and silica rich. This creates a planet where much of the land surface lies beneath sea level (in this case, 0 kilometers elevation), creating ocean basins. ...
