The Ever-Changing Swiss Cheese of Mars
The Ever-Changing Swiss Cheese of Mars
ESP_074829_0945  Science Theme: Climate Change
Mars has a small South Polar cap of carbon dioxide ice. Although this cap persists year round, it is always changing: it has pits and mesas that in some places resemble a slice of Swiss cheese. The pits are expanding because the carbon dioxide is sublimating, but in other places new carbon dioxide deposits are building up on flat ground.

HiRISE monitors many areas of the cap to study these changes. Usually when we study changes, we can align the images with features that haven’t changed, but here that is difficult: nearly everything is different! By lining up the pattern of shallow pits on top of a mesa, which are not changing much, we can see the variations in the eight Mars years between observations (PSP_004992_0945 and this one). Some of the walls have retreated by more than 15 meters (about 50 feet).

Written by: Colin Dundas (narration: Tre Gibbs)  (28 September 2022)
Acquisition date
14 July 2022

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
246.8 km (153.4 miles)

Original image scale range
24.7 cm/pixel (with 1 x 1 binning) so objects ~74 cm across are resolved

Map projected scale
25 cm/pixel

Map projection

Emission angle

Phase angle

Solar incidence angle
64°, with the Sun about 26° above the horizon

Solar longitude
265.4°, Northern Autumn

For non-map projected images
North azimuth:  126°
Sub-solar azimuth:  41.6°
Black and white
map projected  non-map

IRB color
map projected  non-map

Merged IRB
map projected

Merged RGB
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RGB color
non-map projected

Black and white
map-projected   (492MB)

IRB color
map-projected   (288MB)

Black and white
map-projected  (276MB)
non-map           (452MB)

IRB color
map projected  (101MB)
non-map           (278MB)

Merged IRB
map projected  (122MB)

Merged RGB
map-projected  (111MB)

RGB color
non map           (235MB)
10K (TIFF)

B&W label
Color label
Merged IRB label
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EDR products

IRB: infrared-red-blue
RGB: red-green-blue
About color products (PDF)

Black & white is 5 km across; enhanced color about 1 km
For scale, use JPEG/JP2 black & white map-projected images

All of the images produced by HiRISE and accessible on this site are within the public domain: there are no restrictions on their usage by anyone in the public, including news or science organizations. We do ask for a credit line where possible:

NASA’s Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, Calif., manages the Mars Reconnaissance Orbiter for NASA’s Science Mission Directorate, Washington. The HiRISE camera was built by Ball Aerospace and Technology Corporation and is operated by the University of Arizona.