In 1976, NASA's Viking 1 spacecraft was orbiting Mars, snapping photos of possible landing sites for its sister ship Viking 2, when it spotted the shadowy likeness of a human face. It appeared to be an enormous head nearly two miles from end to end staring back at the cameras from a region of the Red Planet called Cydonia.
Imagine the stir in mission control as watching controllers seemed to be watched in return. The surprise was short-lived, though, as scientists recognized another Martian mesa, common enough around Cydonia, only this one had unusual shadows that made it look like an Egyptian Pharaoh.
Hoping to stir up a little interest in Mars and NASA, the folks in public relations released the image along with the following caption:
"This picture is one of many taken in the northern latitudes of Mars by the Viking 1 Orbiter in search of a landing site for Viking 2.
"The picture shows eroded mesa-like landforms. The huge rock formation in the center, which resembles a human head, is formed by shadows giving the illusion of eyes, nose and mouth. The feature is 1.5 kilometers (one mile) across, with the sun angle at approximately 20 degrees. The speckled appearance of the image is due to bit errors, emphasized by enlargement of the photo. The picture was taken on July 25 from a range of 1873 kilometers (1162 miles). Viking 2 will arrive in Mars orbit next Saturday (August 7) with a landing scheduled for early September."
In the years since its release, the "Face on Mars" has become a pop icon. It has been spotted in a Hollywood film, books, magazines, radio talk shows and especially the tabloids. Some people believe the Face provides bona fide evidence of life on Mars -- and that NASA is covering it up. In reality, NASA knows what a boon to its budget it would be if there was an ancient civilization on Mars.
No one around NASA actually believed the Face was an alien artifact, but they made it a priority to photograph Cydonia when Mars Global Surveyor (MGS) arrived at the Red Planet in Sept. 1997 anyway. "We felt this was important to taxpayers," explained Jim Garvin, chief scientist for NASA's Mars Exploration Program. "We photographed the Face as soon as we could get a good shot at it."
Finally, on April 5, 1998, when Mars Global Surveyor flew over Cydonia for the first time, Michael Malin and his Mars Orbiter Camera (MOC) team snapped a picture ten times sharper than the original Viking photos. Thousands of anxious web surfers were waiting when the image first appeared on a JPL web site, revealing ... a natural landform. There was no alien monument after all.
Conspiracy theorists are hard to dissuade, though, so not everyone was satisfied. The Face on Mars is located at 41 degrees north martian latitude where it was winter in April '98 -- a cloudy time of year on the Red Planet. The camera on board MGS had to peer through wispy clouds to see the Face. Perhaps, said skeptics, alien markings were hidden by haze.
Mission controllers decided to try for another peek. "It's not easy to target Cydonia," says Garvin. "In fact, it's hard work." Mars Global Surveyor is a mapping spacecraft that normally looks straight down and scans the planet like a fax machine in narrow 2.5 km-wide strips. "We just don't pass over the Face very often," he noted.
However, on April 8, 2001 -- a cloudless summer day in Cydonia -- Mars Global Surveyor drew close enough for a second look. "We had to roll the spacecraft 25 degrees to center the Face in the field of view," said Garvin. "Malin's team captured an extraordinary photo using the camera's absolute maximum resolution." Each pixel in the 2001 image spans 1.56 meters, compared to 43 meters per pixel in the best 1976 Viking photo.
What the picture actually shows is the Martian equivalent of a butte or mesa -- landforms common around the American West. "It reminds me most of Middle Butte in the Snake River Plain of Idaho," says Garvin. "That's a lava dome that takes the form of an isolated mesa about the same height as the Face on Mars."
No alien lifeforms, just natural Martian landforms. Of course, some people will never be satisfied.