Flying in orbit over Mars, NASA‘s Mars Odyssey orbiter captured a panorama of the Red Planet’s largest volcano, Arsia Mons, peeking out from behind a sea of clouds in 2001. This picturesque moment offers an exceptionally rare view of the Martian volcano, showing the terrain at an angle that captures the planet’s horizon.
“We chose Arsia Mons hoping to see the volcano’s summit rise above the morning clouds. And it didn’t disappoint,” said Jonathon Hill, Odyssey camera operations manager and mission planner at the University of Arizona’s Mars Science Center, which is called the Thermal Emission Imaging System, or THEMIS. THEMIS can view Mars in both visible and infrared light.
Launched in 2001, Odyssey circled Mars for more than two decades, studying the Martian surface. But in 2023, the orbiter began taking breathtaking panoramic images of the Martian horizon. Since CE cannot turn to get these stunning views, the orbiter turns on its side, rotating 90 degrees. In this way, it captured the “limb” of Mars, the edge of the planet’s horizon. This is the fourth limb observation made by THEMIS since 2023.
Odyssey took the image on May 2, just before dawn. In it, Arcia Mons stands 12 miles (20 kilometers) tall and 70 miles (450 km) in diameter. By comparison, the tallest volcano on Earth, Mauna Loa, rises 6 miles (9 km) above the seafloor and is 75 miles (121 km) in diameter.
Arsia Mons is also one of the most cloudy volcanoes on Mars and the southernmost of the three volcanoes of Tharsis that form the Tharsis Montes, or Mountains of Tharsis. These mountains are often surrounded by clouds of water ice, especially in the early morning. The clouds form when air expands as it rises up the mountain slopes and then rapidly cools.
This view also allows scientists to study Martian weather and phenomena such as dust clouds, and how they change over the seasons. Odyssey may be able to take a few more of these panoramas before it is retired, probably at the end of this year.
