A Martian volcano breaks through the clouds in a spectacular image captured by the Odyssey orbiter. This unprecedented view reveals Arsia Mons, one of Mars' largest volcanoes, emerging from a sea of morning clouds.
The Mars Odyssey mission, launched in 2001, primarily aims to map the chemical and mineral composition of the Martian surface. Despite completing its main mission in 2004, the probe continues to study the rocks, clouds, and seasons of the Red Planet. Its observations contribute to a better understanding of the Martian atmosphere.
The shield volcano Arsia Mons pierces through Mars' clouds in this new orbital image from NASA.
Credit: NASA/JPL-Caltech/ASU
To capture this unique image, Odyssey had to perform a 90-degree rotation in its orbit. This maneuver allows the THEMIS camera to capture cloud layers and analyze their composition of dust and water ice. This data is crucial for predicting dust storms, a key factor for future crewed missions.
Arsia Mons, though not as tall as Olympus Mons, dominates the Martian landscape with its 12-mile (20 km) height. Located in the Tharsis Montes volcanic region, this volcano is often shrouded in water-ice clouds, especially at dawn. These cloud formations are particularly visible when Mars is at its aphelion, the farthest point in its orbit from the Sun.
The panoramic image, the fourth of its kind, was created by the probe's THEMIS camera. This instrument, capable of photographing in visible and infrared light, also helps identify areas rich in subsurface water ice. This information could guide the selection of landing sites for the first astronauts on Mars.
The complete panoramic view.
Credit: NASA/JPL-Caltech/ASU Why are Martian volcanoes so large?
Martian volcanoes, like Arsia Mons, are shield volcanoes, similar to those found in Hawaii on Earth. However, their size is much more imposing due to Mars' lower gravity and the absence of plate tectonics.
These volcanoes form through the accumulation of fluid lava flows over millions of years. Arsia Mons, for example, spans about 270 miles (435 km) in diameter, which is far wider than any terrestrial volcano.
The major difference lies in their activity. While Earth's volcanoes are often active, those on Mars are considered extinct for millions of years. This offers scientists a unique window into the planet's geological history.