Newer satellite images have lifted the face off Mars

Viking 1 captures the visage that launched a thousand conspiracy theories

By Richard Stenger
CNN

(CNN) -- The legendary face of Mars has graced tabloid newspaper covers, inspired theories of alien civilizations and starred in a Hollywood film. But new high-resolution satellite images unmask the truth underneath the peculiar rock formation.

Twenty-five years ago, NASA's Viking 1 spacecraft was circling the red planet, taking pictures of possible landing sites for a sibling NASA probe, Viking 2, when it caused a sensation.

Zooming in on a region of Mars called Cydonia, Viking I spotted what resembled a human face cloaked in shadows, complete with darkened eyes, narrow nose and frowning mouth, giving it the countenance of an Egyptian pharaoh.

NASA scientists reasoned that sunlight was playing tricks with just another mesa in the Cydonia region, where such formations are common.

But the Viking image sparked the imagination of the public. Anointed the Face of Mars, the two-mile long feature led some to conclude that the planet once hosted intelligent life.

NASA dismissed that idea because the agency wanted to hide such knowledge, conspiracy theorists maintained. The space agency had to wait almost a generation to take another look.

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Able to resolve objects as small as an airplane, the Mars Global Surveyor aimed its stronger eye on the landform in April 1998, months after it arrived in orbit.

"We photographed the Face as soon as we could get a good shot of it," said Jim Garvin, a NASA Mars scientist.

The image, ten times sharper than the one from Viking, unmasked the Face, finding only a natural landform underneath. Some were unconvinced. The Surveyor satellite snapped the picture during the Cydonian winter. Perhaps the wispy seasonal fog shrouded the Face from view, they argued.

The Surveyor took another close-up picture in April of this year, then summer in the area. Without clouds or shade, the Face clearly became just another mesa or butte dotting the landscape in Cydonia.

Global Surveyor data was used to compose this more accurate, less flattering portrait of the Mars face

NASA released the new image this week, along with other Surveyor observations that further debunk the Face. The satellite's laser altimetry, which can measure the precise elevations of features to within 1 foot found no eyes, no nose and no mouth.

"All of its dimensions, in fact, are similar to the other mesas. It's not exotic in any way," Garvin said.

Still, planetary geologists have great interest in the mesas of Cydonia, a curious transition zone between smooth lowlands in the north and crater-pocked highlands in the south. Some theorize that Cydonia once bordered an ancient ocean.

"Ocean advocates say the mesas are just what you would expect to see near the edge of the water (but) there are many possibilities," Garvin said. Glaciers, winds or tectonic shifts also could have formed the mesa and buttes, which resemble those in the American West, he added.

Perhaps only a field trip will solve the mystery. And just in case, Garvin has taken advantage of a new three-dimensional map to chart a nature trail to the top of the best known martian mesa.

"The start and midsection of the hike would be easy, with some steep flanks in between. It would take about two hours to reach the summit. From there the view would be spectacular."

But, Garvin cautions, hikers should bring plenty of water and oxygen.