). Cydonia was first imaged in detail by the
Viking 1 and
Viking 2 orbiters. Eighteen images of the Cydonia region were taken by the orbiters, of which seven have resolutions better than 250 m/
pixel (820 ft/pixel). The other eleven images have resolutions that are worse than 550 m/pixel (1800 ft/pixel) and are of limited use for studying surface features. Of the seven good images, the lighting and time at which two pairs of images were taken are so close as to reduce the number to five distinct images. The
Mission to Mars: Viking Orbiter Images of Mars CD-ROM set image numbers for these are: 035A72 (VO-1010), 070A13 (VO-1011), 561A25 (VO-1021), 673B54 & 673B56 (VO-1063), and 753A33 & 753A34 (VO-1028). In one of the images taken by
Viking 1 on July 25, 1976, a Cydonian mesa, situated at 40.75° north
latitude and 9.46° west
longitude, had the appearance of a
humanoid face. When the image was originally acquired, Viking chief scientist
Gerald Soffen dismissed the "Face on Mars" in image 035A72 as a "trick of light and shadow". A second image, 070A13, also shows the "face", and was acquired 35 Viking orbits later at a different sun-angle from the 035A72 image. This latter discovery was made independently by Vincent DiPietro and Gregory Molenaar, two computer engineers at
NASA's
Goddard Space Flight Center. DiPietro and Molenaar discovered the two misfiled images, Viking frames 035A72 and 070A13, while searching through NASA archives. The resolution of these images was of about 50 m/pixel.
Later imagery More than 20 years after the
Viking 1 images were taken, a succession of spacecraft visited Mars and made new observations of the Cydonia region. These spacecraft have included NASA's
Mars Global Surveyor (1997–2006) and
Mars Reconnaissance Orbiter (2006–present), and the
European Space Agency's
Mars Express probe (2003–present). In contrast to the relatively low resolution of the Viking images of Cydonia, these new platforms afford much improved resolution. For instance, the
Mars Express images are at a resolution of 14 m/pixel (46 ft/pixel) or better. By combining data from the
High Resolution Stereo Camera (HRSC) on the
Mars Express probe and the Mars Orbiter Camera (MOC) on board NASA's
Mars Global Surveyor it has been possible to create a three-dimensional representation of the "Face on Mars". Since it was originally first imaged, the face has been accepted by scientists as an
optical illusion, an example of the psychological phenomenon 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, the Romanian
Sphinx,
Giewont, the
Pedra da Gávea, the
Old Man of Hoy,
Stac Levenish,
Sleeping Ute, and the
Badlands Guardian.
Speculation The Cydonia facial pareidolia inspired individuals and organizations interested in
extraterrestrial intelligence and
visitations to Earth, and the images were published in this context in 1977. Some commentators, most notably
Richard C. Hoagland, believe the "Face on Mars" to be evidence of a long-lost
Martian civilization along with other features they believe are present, such as apparent
pyramids, which they argue are part of a
ruined city. While accepting the "face" as a subject for scientific study, astronomer
Carl Sagan criticized much of the speculation concerning it in the chapter "The Man in the Moon and the Face on Mars" in his 1995 book
The Demon-Haunted World. The
shape-from-shading work by Mark J. Carlotto was used by Sagan in a chapter of his famous
Cosmos series. In 1998, a news article about the "Space Face" quoted a scientist talking about deciphering "intelligent design" in nature. A cutting of this was used by
Charles Thaxton as an overhead visual for a lecture at
Princeton, in his first public use of the term "
intelligent design" as a substitute for
creation science. The "face" is also a common topic among
skeptic groups, who use it as an example of
credulity. They point out that there are other faces on Mars but these do not elicit the same level of study. One example is the
Galle Crater, which takes the form of a
smiley, while others resemble
Kermit the Frog or other celebrities. On this latter similarity,
Discover magazine's "Skeptical Eye" column ridiculed Hoagland's claims, asking if he believed the aliens were fans of
Sesame Street. ==See also==