Spiders in the Summer
NASA/JPL/University of Arizona
Spiders in the Summer
PSP_004748_0945  Science Theme: Seasonal Processes
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The south polar region of Mars contains numerous features dubbed "spiders." These are actually narrow shallow channels carved in the ground, probably by gas escaping as the seasonal dry ice cap sublimates (evaporates directly from solid ice to gas).

In the spring they are the source of fans of dust. In the summer, the dark fans are only barely discernible from the surface material, because they are the surface material. Dust gets blown to the top of—and deposited on— the seasonal layer of ice as the seasonal cap sublimates.

Although the fans fade away in the summer, the spider channels remain clearly visible (2254 x 1522; 3 MB). Small patches of bright seasonal ice still remain in a few places. Written by: Candy Hansen  (29 August 2007)
Acquisition date
01 August 2007

Local Mars time:

Latitude (centered)

Longitude (East)

Spacecraft altitude
246.4 km (154.0 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
65°, with the Sun about 25° above the horizon

Solar longitude
287.4°, Northern Winter

For non-map projected images
North azimuth:  125°
Sub-solar azimuth:  49.4°
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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/JPL/University of Arizona

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.