There must have been some degree of surprise among the mission controllers at the Jet Propulsion Lab when the face appeared on their monitors. But the sensation was short-lived. Scientists thought it was just another Martian mesa, fairly common around Cydonia, only this one had unusual shadows that made it look like an Egyptian pharaoh.
What is a mesa?
This image from the Mars Global Surveyor (MGS) of the Mars Orbiter Camera (MOC) shows two mesa in the northern plains of Mars. “Mesa” is the Spanish word for “table”. This is an excellent description of the two elliptical features captured in this image. In both cases, the tops of the mesa and the material beneath, down to the level of the surrounding, rugged plain, are the remains of an extensive layer(s) of material that has been largely eroded. The circular feature near the center of the larger mesa is, usually, the buried site of an impact crater.
First seen in 1976 in Cydonia
One of these massive visible remnants became famous as the “Face on Mars” captured in an image taken on July 25, 1976 by the American Viking 1 Orbiter. A few days later, on July 31, 1976, a press release from NASA stated that the formation “resembles a human head”. However, NASA scientists had already correctly interpreted the image as an optical illusion. This illusion was caused by the angle of illumination of the Sun, the morphology of the surface and the shadows. These give the impression of eyes, nose and mouth.
However, the “Face on Mars”has been the subject of widespread speculation as to its possible origins. The series of nearby structures have been interpreted by some space enthusiasts as man-made landscapes, as potential pyramids, and even as a disintegrated city. The idea that the planet may have once been home to intelligent beings has since inspired the imaginations of many Mars fans, which has helped it become a huge hit.
The importance to planetary geologists of Cydonia
Although the formations are not alien in origin, they are still of considerable interest to planetary geologists. In areas surrounding Cydonia slightly sloping areas surrounding hills or ridges, so-called “debris aprons”, are common. These, form at the foot of such mounds and probably consist of a mixture of rocky debris and ice. The formation of debris deposits is thought to be controlled by the formation of talus, a sloping mass of rocky debris at the base of a cliff.
The former larger debris plots may have been covered by subsequent lava flows in the surrounding area; the western wall has moved downward as a coherent mass. The location of the detachment zone is reflected by a broad escarpment extending north-south.
Between April 2004 and July 2006, the HRSC collected data from the region of Cydonia numerous times. However,the high flight altitude, resulting in poor resolution of ground-based data (orbits 0262, 2533, 2872), as well as dust and haze in the Martian atmosphere, have resulted in severely reduced data quality that have prevented the acquisition of high quality images.
After multiple attempts to capture the Cydonia region, the High Resolution Stereo Camera (HRSC) aboard the Mars Express has finally obtained, on July 22, a series of images showing the famous “face” on Mars with unprecedented detail. The data was collected during orbit 3253 over the Cydonia region, with a ground resolution of about 13.7 meters per pixel. Cydonia is located at about 40.75° north and 350.54° east.
These images of the Cydonia region on Mars are really spectacularDr.Agustin Chicarro, ESA
Cydonia is located in the Earth Arabia region on Marte and belongs to the transition zone between the southern highlands and the northern plains of Marte. This transition is characterized bylarge debris-filled valleys and isolated mounds of remains of various shapes and sizes.
Mars is a special place, it reminds us of home…someday we will go there.Jim Garvin, chief scientist Mars Explorer
That’s why “Face on Mars” was so popular: it reinforced a connection between planet Earth and Mars. But, even without an alien monument, future explorers will have a lot to do. Climbing the highlands of Cydonia will be just the beginning.