The pictures are at
Twenty five years ago something funny happened around Mars. NASA’s Viking 1 spacecraft was circling the planet, snapping photos of possible landing sites for its sister ship Viking 2, when it spotted the shadowy likeness of a human face. An enormous head nearly two miles from end to end seemed to be staring back at the cameras from a region of the Red Planet called Cydonia.
There must have been a degree of surprise among mission controllers back at the Jet Propulsion Lab when the face appeared on their monitors. But the sensation was short lived. Scientists figured it was just another Martian mesa, common enough around Cydonia, only this one had unusual shadows that made it look like an Egyptian Pharaoh.
Above: A 1976 Viking 1 photograph of the Face on Mars. Click here for a 2001 photo from Mars Global Surveyor that reveals the true appearance of the Face.
A few days later NASA unveiled the image for all to see. The caption noted a “huge rock formation … which resembles a human head … formed by shadows giving the illusion of eyes, nose and mouth.”
On 25 July, 1976, it photographed a region of buttes and mesas along the escarpment that separates heavily cratered highlands to the south from low lying, relatively crater-free, lowland plains to the north. Among the hills was one that, to the Viking investigators scrutinizing the images for likely landing sites, resembled a face. Owing to the importance of the landing site search, and with a desire to provide the public with at least one familiar-looking landform amid the craters and exotic terrains found all over Mars, an image including the face-like hill was released as part of the Jet Propulsion Laboratory’s public relations effort. The text of that release notes the face-like hill.
Today, the “Face” is generally accepted to be an optical illusion, an example of pareidolia. After analysis of the higher resolution Mars Global Surveyor data NASA stated that “a detailed analysis of multiple images of this feature reveals a natural looking Martian hill whose illusory face-like appearance depends on the viewing angle and angle of illumination“. Similar optical illusions can be found in the geology of Earth; examples include the Old Man of the Mountain and the Badlands Guardian, which resembles a human head wearing a Native American headdress.
Figure 4. Left: negative of the Face as seen by the MGS spacecraft in April, 1998. Center: Lighting source switched from SE to NW. Right: Viewing angle switched from 45° west to overhead. Click on above image to view full animation by Mark Kelly, whose web site is <www.electrobus.com>. Need an animation viewer? Click here and see link at end of page.