Candidate Cavern Entrance Northeast of Arsia Mons
NASA/JPL/University of Arizona
Candidate Cavern Entrance Northeast of Arsia Mons
PSP_003647_1745  Science Theme: Tectonic Processes

This image shows a very dark spot on an otherwise bright dusty lava plain to the northeast of Arsia Mons, one of the four giant Tharsis volcanoes.

This is not an impact crater as it lacks a raised rim or ejecta. What's amazing is that we cannot see any detail in the shadow! Here we see this dark spot and a version that is "enhanced" to view the darkest area, yet we still cannot see details except noise.

The HiRISE camera is very sensitive and we can see details in almost any shadow on Mars, but not here. We also cannot see the deep walls of the pit. The best interpretation is that this is a collapse pit into a cavern or at least a pit with overhanging walls. We cannot see the walls because they are either perfectly vertical and extremely dark or, more likely, overhanging.

The pit must be very deep to prevent detection of the floor from skylight, which is quite bright on Mars.

Written by: Alfred McEwen   (23 May 2007)

This is a stereo pair with PSP_004847_1745.

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Acquisition date
07 May 2007

Local Mars time:

Latitude (centered)

Longitude (East)

Range to target site
252.5 km (157.8 miles)

Original image scale range
25.3 cm/pixel (with 1 x 1 binning) so objects ~76 cm across are resolved

Map projected scale
25 cm/pixel and North is up

Map projection

Emission angle:

Phase angle:

Solar incidence angle
52°, with the Sun about 38° above the horizon

Solar longitude
233.4°, Northern Autumn

North azimuth:

Sub-solar azimuth:
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non-map           (231MB)

Merged IRB
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Merged RGB
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RGB color
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Full resolution JP2 download
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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

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NASA/JPL/University of Arizona

For information about NASA and agency programs on the Web, visit: 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. Lockheed Martin Space Systems is the prime contractor for the project and built the spacecraft. The HiRISE camera was built by Ball Aerospace and Technology Corporation and is operated by the University of Arizona. The image data were processed using the U.S. Geological Survey’s ISIS3 software.