While many a whimsical image has been “seen” in the craters and shadows of the moon, by people with their feet planted firmly on Earth, never has such a stir been made as when the “face” of Mars was revealed in July of 1976.
The Viking 1 Orbiter, while cruising over the Cydonia region in the northern latitudes of Mars, snapped the photo that would make the scientific world gnash their technical teeth. What was the image photographed while looking for a landing place for the next Viking mission?
The first image released to the public is grainy, due to bit errors in enlarging the picture. And enlarged it is, since the photo was taken at a distance of 1162 miles. But it shows what appears to be a head with humanoid features gently breaking the dusty surface of Mars. The general area, which resembles mesas on Earth, had no identifying landmarks that would distinguish the location, until the camera panned over the mysterious visage.
Was it left by the occupants of an ancient millennium? Or was it simply the 20 degree angle of the sun, and the accompanying shadows, turning hills and rock formations into something that wasn’t there? Reminiscent of the Easter Island stone heads, the actual formation far outstrips them in size, being a mile across and some three miles long by calculations.
The Viking photographs have literally been examined from every possible angle. Malin Space Science Systems subjected the various images to a number of procedures, by which the features on the planet surface could be examined. They applied bit error correction, reseau removal and some brightness alteration, before projecting them onto a standard map view. They did not perform contrast/brightness or image sharpening, as that would have altered the features, according to the type of monitor they were viewed on. MSSS scientists then applied their own “shape-from-shading” technique, producing vertical views of the height field. This allowed them to reproduce the image with the shadows it would have at different hours of the day, bearing in mind that the form itself is located above the Martian Tropic of Capricorn, and would always be illuminated in nature, from the South. When the image was mapped directly onto the topography, they were able to produce views of the “face” from different angles, including surface level.
Did this resolve the question of what they were looking at? No. For twenty years, a cult would grow up around the image, and other surrounding surface features of Mars, which included one distinct pyramid shape, and nearby, a group of similar shapes, known as “The City”.
In 1997 the Mars Global Surveyor arrived to capture new and enhanced images of the planet. A Mars Orbital Camera then began snapping new pictures of the “face” in May of 1998. This time the spacecraft passed a mere 275 miles up. The angle of the “morning” sun was 25 degrees, approximating the conditions of the Viking photographs, but at ten times the resolution of the 1976 photographs.
Scientists then lined up the Viking image, the MOC image, reduced in proportion to equal that of the Viking photo, and even a second MOC image, with the light and dark portions reversed. The end result was simply a good view of indistinguishable hills and gullies, in a slightly raised area that has the shape of a tablet, or headstone.
On Hallowe’en, 2002, NASA/ASU/THEMIS released new night images taken of the face, by the Mars Odyssey spacecraft cameras. An even closer and higher resolution view of the “face”, shows it to be nothing more than a three kilometre long knob of sediments, eroded by time and the fierce Martian winds.
What the comparison of the day and night images did show scientists, was the heat holding capacity of various rocks and sand, since many features seen in day photos, did not show up on the infrared images taken at night. However, this very discovery put NASA on the hot seat, when a comparison was made of the daytime photos released July 24th, 2002 and the night shots of October 31st. The night photos had much more detail than the day photos. In fact, on July 25th, a NASA contractor downloaded to their THEMIS website, a much higher resolution daytime photo than the one released to the public. NASA later released what they claimed to be the same image. The second image showed many more features on the terrain, and left the public wondering if NASA is holding back anything else.