NASA spots Martian volcano twice the height of Mount Everest bursting through the morning clouds: Space photo of the week

What's better than the sight of clouds on Mars? The view of a volcano rising above them! This stunning panorama shows the ancient Martian volcano Arsia Mons peeking through clouds on the Red Planet. The image was captured by NASA's Mars Odyssey orbiter just before the first rays of sunlight illuminated the planet on May 2.

The Mars Odyssey mission was launched in 2001 to map the chemical elements and minerals on the Martian surface. Although it completed its primary mission in 2004, it has continued mapping the Red Planet's surface rocks, studying its clouds and fog, and monitoring its seasons ever since.

In 2023, Odyssey started taking high-altitude images of the edge of Mars' horizon, or "limb," like the one shown here. Because the orbiter's cameras are built to capture and study the Martian surface, it can be tricky to snap images of the planet's clouds.

To do so, Odyssey rotates 90 degrees in its orbit so the camera can capture the cloudy layers and see the dust and water ice inside them. Scientists study the Martian atmosphere to learn about the variations in seasons that hint at how the atmosphere evolves. This knowledge can help them anticipate intense winds and dust storms, which are important factors for planning the entry, descent and landing of future missions.

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In the new panorama photo, the Martian atmosphere appears as a greenish haze as Arsia Mons, one of the largest volcanoes on Mars, rises out. Appearing as a dark blob, it peeks above the morning cloud tops, marking the first time a volcano has been imaged on the Red Planet's horizon. Although Arsia Mons is not the tallest volcano on Mars (that honor goes to Olympus Mons), it stands 12 miles (20 km) high, which is more than twice the height of Earth’s highest mountain, Mount Everest.

Arsia Mons is a shield volcano, named for its resemblance to a shield, located in the Tharsis Montes volcanic region on Mars, which includes two other shield volcanoes: Pavonis Mons and Ascraeus Mons. This volcanic region is frequently surrounded by clouds of water ice, with Arsia Mons being the cloudiest of the three, particularly in the early morning. By contrast, carbon dioxide clouds are more prevalent on Mars.

The thick canopy of early-morning clouds is particularly prominent when Mars is at its farthest point from the sun, known as aphelion. During this time, the clouds that form around the equator are known as the aphelion cloud belt. These early-morning clouds are seen parading around Arsia Mons in the image.

The new panorama that marks the fourth "limb" observation was captured by the Thermal Emission Imaging System (THEMIS) camera on the 24-year-old orbiter. THEMIS, which takes pictures in visible and infrared light, helps scientists map the subsurface areas that contain water ice. Identifying such areas could be helpful for deciding the landing sites for the first astronauts on Mars.

For more sublime space images, check out our Space Photo of the Week archives.