9 - Lava worlds: Cosmic cousins

Abstract

All solid planetary bodies in the in the Solar System are either currently volcanically active or have been active in the past. By comparing the volcanic compositions and eruption styles observed throughout the Solar System, commonalities and differences help to reveal how different planetary bodies, with distinct chemical makeup, have evolved through time. The inner planets appear to be dominated by effusive eruptions of low-viscosity basaltic lava, although the behavior of those lavas is different on each body. The longest channel in the Solar System, for example, is a lava channel on Venus. Jupiter's innermost moon Io has been called the most volcanically active body in the Solar System because at any given time, ~20 volcanoes are erupting on its colorful surface. In the outer Solar System, cryovolcanism—ice-dominated lavas and magmas—is common; Saturn's moon Enceladus spews active water geysers that help to feed Saturn's rings. Even large asteroids, such as Ceres, display evidence of volcanism. Although Mars' volcanoes are the largest in the Solar System, Mars' volcanic processes are not unique.