“The Little Pit” image from NASA’s Mars Reconnaissance Orbiter.
This image of a small hole on the surface of Mars is being widely shared on social media alongside suggestions that it could be an opening into a cave and even host alien life. It’s also been suggested that it could shelter future astronauts.
Where The Image Comes From
“The Little Pit” image was taken on August 15, 2022, by the Mars Reconnaissance Orbiter, which has spent the last 18 years imaging the red planet’s surface. The image was originally shared online on May 21.
It was shared by the University of Arizona, whose daily HiPOD sees the sharing of an image from MRO’s HiRISE camera. HiRISE stands for High Resolution Imaging Science Experiment.
Another pit—possibly the entrance to a lava tube—as imaged by HiRISE in 2020.
What The Image Shows
The object in the image is a pit crater just a few meters across on the flank of Arsia Mons, one of three large extinct shield volcanoes near the equator on Mars, known as the Tharsis region. According to NASA’s Jet Propulsion Laboratory, Arsia Mons is 270 miles (450 kilometers) in diameter, almost 12 miles (20 kilometers) high, and the summit caldera is 72 miles (120 kilometers) wide. Its caldera alone is larger than many volcanoes on Earth.
According to the image’s caption, pits may reflect geologically recent tectonic or volcanic activity. It also suggests that if it is the entrance to a cave, it could be a target for future robotic exploration.
Incipient Pit Crater in the Arsia Chasmata.
Why Caves On Mars Are Exciting
Caves and lava tubes beneath the surfaces of the moon and Mars—particularly common around shield volcanoes—are potential places for astronauts to visit. Lava tubes were formed when underground rivers of lava emptied out.
According to Astronomy magazine, such crevices could protect astronauts from harmful radiation, extreme temperatures and micrometeorites. JPL has already researched ways of exploring extraterrestrial caves and lava tubes for signs of life and potential future habitation.
“The Little Pit” is far from the only pit crater imaged by HiRISE. In 2020, HiPOD published another image of a pit crater, possibly the entrance to a lava tube. It’s thought that the 50 meters (150 feet) across entrance leads to a lava tube of at least the same dimensions—making it far bigger than any lava tube found on Earth. Another image of a pit crater was published in 2009.
This is a map of the Martian surface showing the location of the Arsia Mons volcano.
New Volcano
In March, scientists announced they had found a deeply eroded giant shield volcano on Mars and named it Noctis Mons. With slopes extending 140 miles (225 kilometers), it’s within a region of Mars called the Eastern Noctis Labyrinthus. It becomes the seventh largest volcano on Mars, the biggest being Olympus Mons, which, at 72,000 feet (21,950 meters) tall, is the largest in the solar system.
Noctis Mons is in the same region where in 2022 a relict glacier was discovered—salt that formed on top of a glacier, preserving its shape, even its crevasses—suggesting the possibility that ice may still exist just under the surface of Mars.
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Dr. Thomas Hughes is a UK-based scientist and science communicator who makes complex topics accessible to readers. His articles explore breakthroughs in various scientific disciplines, from space exploration to cutting-edge research.
