Solar System Volcanoes Evidence of past volcanic activity has been found on most planets in our solar system and on many of their moons. Our own moon has vast areas covered with ancient lava flows. Mars has Olympus Mons and Tharsis Rise, the largest volcanic features in our solar system. The surface of Venus is covered with igneous rocks and hundreds of volcanic features.
Most of the volcanic features discovered within our solar system formed millions of years ago – when our solar system was younger and the planets and moons had much higher internal temperatures. Geologically recent volcanic activity is not as widespread. Based upon observations from Earth and from space vehicles, only four bodies in the solar system have confirmed volcanic activity. These are 1) Earth; 2) Io, a moon of Jupiter; 3) Triton, a moon of Neptune; and, 4) Enceladus, a moon of Saturn.