While volcanoes have brought profound changes to landscapes here on Earth, volcanic activity on other planets and moons has followed a different path. It's easy to imagine space volcanoes as even more ferocious and devastating versions of the ones scattered across Earth, but in reality, most of them have fallen into dormancy.
Volcanic features have been observed on our fellow rocky planets, Venus and Mars, but they largely appear to be inactive right now. Some scientists, however, have suggested that current volcanic activity on Mars and Venus may not be so far-fetched after all, with new evidence emerging from recent studies.
What Gave Earth Its Volcanoes?
Earth boasts more than 1,500 potentially active volcanoes, with 50 to 70 erupting every year. But why is our planet so volcanically active? The answer lies in plate tectonics, the movement of divided plates that make up Earth’s crust.
Tectonic shifts — caused by heat-driven currents below the crust — sculpt the planet’s most memorable landmarks, from mountain ranges to ocean trenches. The interactions of plates have also guided magma to the surface and spawned volcanoes, both by moving away from each other and pushing against each other.
A third process behind volcano creation relates to hotspots, areas of Earth’s mantle where magma rises up from the depths of the planet. When a plate moves over a hotspot, a chain of volcanoes is created.
The surfaces of other rocky planets appear to have been affected by ancient volcanic activity, but this would not have been caused by plate tectonics, a geological process that is exclusive to Earth. A more likely explanation is that volcanic features on these planets were created by hotspot-like activity or other variations of tectonics.
Read More: Olympus Mons: Mars' Mega Volcano
Volcanism on Venus and Mars
Various volcanic features can be found on the rocky planets neighboring Earth. Mars contains volcanic plains formed by past eruptions and inactive shield volcanoes that are much more massive than Earth’s volcanoes; Olympus Mons, the largest volcano in the entire Solar System, stands at about 2.5 times the height of Mt. Everest. This volcano is located in the Tharsis region of Mars, which is home to other similarly colossal volcanoes built from basaltic lava that welled up from deep within the planet.
The verdict on whether or not Mars is still capable of being volcanically active doesn’t appear to be set in stone. While the planet experienced intense eruptions over hundreds of millions of years, it has since cooled and ceased most activity. However, a few lingering signs — like “marsquakes” and magma movement — hint that Mars may not be completely idle.
The same uncertainty has been true for Venus, until recently; while scientists previously believed that Venus’ volcanoes were inactive, new evidence is starting to push back against this notion.
A 2023 study using data and images from NASA’s Magellan mission (launched in 1989) found that a volcanic vent associated with Maat Mons, a shield volcano, changed in size and shape between February and October 1991. Another study published in 2024 built upon this discovery, identifying two locations where the formation of new rock may represent solidified lava from volcanic activity between 1990 and 1992.
Although this seemingly confirms that Venus is still volcanically active, more information will need to be gathered by NASA’s VERITAS mission, slated to launch in 2031 to study the planet’s surface.
Volcanoes Across Moons
Several moons across the Solar System also feature volcanic mysteries. Ancient volcanic activity shaped the lunar crust of Earth’s own Moon — lunar maria, basaltic plains visible on the Moon, are the result of lava flows filling basins that were left by meteorite impacts.
Cryovolcanoes on icy moons like Triton (a moon of Neptune) and Enceladus (a moon of Saturn) function similarly to typical volcanoes, but they spew material like water, ammonia, and methane instead of molten rock.
The one member of our Solar System that surpasses Earth in volcanic vitality is Io, Jupiter’s innermost moon. Containing around 400 powerful volcanoes, Io is influenced by Jupiter’s gravitational pull and the pull of the planet’s other moons. This tug-of-war causes layers of rock beneath Io’s surface to jostle and heat up, melting solid rock into magma.
Read More: There are More Than 85,000 Volcanoes on Venus
Article Sources
Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:
British Geological Survey. How volcanoes form
The University of Arizona. Recent volcanism on Mars reveals a planet more active than previously thought
NASA Jet Propulsion Laboratory. NASA’s Magellan Data Reveals Volcanic Activity on Venus
NASA Jet Propulsion Laboratory. Ongoing Venus Volcanic Activity Discovered With NASA’s Magellan Data
The Planetary Society. Mind-blowing pictures of the solar system's most volcanic worlds
Jack Knudson is an assistant editor at Discover with a strong interest in environmental science and history. Before joining Discover in 2023, he studied journalism at the Scripps College of Communication at Ohio University and previously interned at Recycling Today magazine
