ONDON, May 26 . - New pictures taken from a NASA spacecraft orbiting Mars have debunked one of the most persistent myths surrounding the Red Planet: the famous "Martian face".

NASA always insisted it was a natural rock formation but conspiracy theorists pronounced it a monument built by an ancient alien civilization. New technology has revealed that it is neither a monument nor a face.

The first clear, high - resolution images of the formation, taken from the Mars Global Surveyor spacecraft, show it is a rocky outcrop similar to Uluru, formerly known as Ayers Rock, Australia, or the landforms of America's Monument Valley in Arizona.

The pictures are 10 times sharper than the Viking images of 1976 and, unlike similar ones in 1998, they were taken on a cloudless day in the Martian summer, offering the best view yet.

Further evidence that the structure is natural has come from measurements taken from a laser altimeter, which show its contours are similar to other formations, and that the eyes, nose and mouth of the original photograph are blurry optical illusions.

Mr. Jim Garvin, chief scientist of NASA's Mars exploration programme, said he took new pictures of the area because of public interest in the face. "We felt this was important to taxpayers," he said. "We photographed the face as soon as we could get a good shot at it. It's not easy to target." On 8 April, 2000, the Global Surveyor took its most recent look. "We had to roll the spacecraft 25 degrees to center the face in the field of view," Dr Garvin said. "One observer said : 'Gee, it doesn't look like a face to me!'

"As a rule of thumb, you can discern things in a digital image three times bigger than the pixel size. So, if there were objects in this picture like airplanes on the ground or Egyptian style pyramids or even small shacks, you could see what they were.

"We took hundreds of altitude measurements of the mesa-like features, including the Face. The height of the Face, its volume and aspect ratio - all of its dimensions, in fact - are similar to the other mesas. It's not exotic in any way."

Similar structures are found on Earth, Dr Garvin said. "It reminds me most of Middle Butte in the Snake River Plain of Idaho. That's a lava dome that takes the form of an isolated mesa about the same height as the Face on Mars."

Dr Garvin remains keen to send astronauts to the formation should a manned mission to Mars be organized. NASA's information about the Face is now so detailed that it is possible to calculate what it would be like to climb.

He said: "An apron of boulders around the base would make the climb difficult, but a human could do it well. It would take about two hours to reach the summit. From there the view would be spectacular."

The Statesman : SPACE

27 May 2001