What Can the Solar System Teach Us About Rocky Exoplanets?

The geological, geochemical, and geophysical properties of the rocky inner Solar System worlds provide us with a basic set of rules for understanding rocky planets generally. Although many of the details differ, there are broad similarities between the inner Solar System worlds—including composition, interior structure, and geological evolution. Farther from the Sun, the icy satellites of the giant planets show clear similarities, even when subject to different orbital dynamical environments, with each other and in some regards with their inner Solar System neighbours. Some types of exoplanet, such as super-Earths and sub-Neptunes, are notably missing from the Solar System. Yet our planetary siblings are similar enough that we can begin to paint, at least in broad strokes, a picture of how rocky planetary bodies form and develop in planetary systems beyond our own.