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Inca City on Mars

Inca City on Mars

Image Title: Inca City on Mars
Release Date: September 25, 2006
Source: Mars Global Surveyor


The Martian feature known as "Inca City" was first observed by the Mariner 9 mission to Mars in 1972. These rectilinear ridges were dubbed the "Inca City" by the scientists working on the Mariner 9 program due to their resemblance to Incan ruins. This feature was subsequently observed by the Viking orbiter mission to Mars. Several explanations have been put forward to explain this pattern of rectilinear ridges. Hypothesis have included fossilized dunes, tectonic faulting, dikes, fractures, etc.

Images returned by the Mars Global Surveyor have pointed to a new possible explanation for the presence of these ridges: an ancient impact event. In addition to the MGS MOC narrow angle camera image shown above, the feature was also a target of the MGS MOC wide angle camera. This image is shown in Figure 1 below.

Mars Global Surveyor MOC wide angle camera view of the Inca City
Fig. 1 Mars Global Surveyor MOC wide angle camera view of the Inca City

The wide angle image covers an area of about 117 square kilometers with a resolution of 242 meters per pixel and was acquired in October 2001. The somewhat circular nature of the feature at the larger scale suggests an impact origin for the ridges, with the original ridge-forming crater having been filled in with sediments over time and then more recently having been partially exhumed revealing the ridges.

In comparing the narrow angle camera image with the wide image, note the color difference. This color difference is a consequence of my having used different false coloring techniques on the two images.

Source Image Background

The source image was acquired by the Mars Global Surveyor Narrow Angle Camera in January 1998. The center of the image is at 81.48 south latitude 64.63 west longitude. The area shown in the image is approximately 30 kilometers wide.

Image Processing

All processing of this image was done using Adobe Photoshop. This includes noise removal, the application of false color, contrast enhancement and tonal adjustments.

Wallpaper Download

I have created a compressed low resolution version of "Inca City on Mars" for use as a desktop wallpaper. This wallpaper version is made available for your personal use only. It is not to be modified or redistributed in any form by any means. All rights are retained by the artist.

Inca City on Mars Wallpaper
Inca City on Mars, 1024 x 768 Wallpaper Image by Jim Plaxco

2005 Jim Plaxco,