Mars Crater or Collapse? A Photo Mystery in Martian 'Swiss Cheese'

dimple on mars, south polar pit, crater
This photo from NASA's Mars Reconnaissance Orbiter shows a crater or pit in the planet's southern hemisphere, where it is currently summer. Carbon dioxide ice gives the region a "swiss cheese" look in this view released June 2, 2017. (Image credit: NASA/JPL-Caltech/University of Arizona)

Scientists aren't sure if a big dimple on Mars came from something smacking into the Red Planet's surface or if was simply caused by a collapse.

A new image from NASA's Mars Reconnaissance Orbiter (MRO) shows several shallow pits among carbon dioxide ice, nicknamed "Swiss cheese terrain" because it looks a bit like the famous cheese.

But at upper right is a deeper pit that goes through the ice and dust, which NASA says could be an impact crater or some sort of collapse pit. [See more amazing Mars photos by MRO]

The picture was taken in the southern hemisphere of Mars late in the summer and unveiled Friday (June 2). At the time the image was taken, the sun was low in the Martian sky and the shadows it cast allowed for more "subtle" topography to show in the image, NASA officials.

MRO takes detailed pictures of the surface using the University of Arizona's High Resolution Imaging Science Experiment (HiRISE) camera. The spacecraft launched in 2005 and has been orbiting Mars since 2006.

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Elizabeth Howell
Staff Writer, Spaceflight

Elizabeth Howell (she/her), Ph.D., is a staff writer in the spaceflight channel since 2022 covering diversity, education and gaming as well. She was contributing writer for for 10 years before joining full-time. Elizabeth's reporting includes multiple exclusives with the White House and Office of the Vice-President of the United States, an exclusive conversation with aspiring space tourist (and NSYNC bassist) Lance Bass, speaking several times with the International Space Station, witnessing five human spaceflight launches on two continents, flying parabolic, working inside a spacesuit, and participating in a simulated Mars mission. Her latest book, "Why Am I Taller?", is co-written with astronaut Dave Williams. Elizabeth holds a Ph.D. and M.Sc. in Space Studies from the University of North Dakota, a Bachelor of Journalism from Canada's Carleton University and a Bachelor of History from Canada's Athabasca University. Elizabeth is also a post-secondary instructor in communications and science at several institutions since 2015; her experience includes developing and teaching an astronomy course at Canada's Algonquin College (with Indigenous content as well) to more than 1,000 students since 2020. Elizabeth first got interested in space after watching the movie Apollo 13 in 1996, and still wants to be an astronaut someday. Mastodon: