Nasa: No face - honest

Does it look like a face?

By BBC News Online science editor Dr David Whitehouse

For those who still think it is a face, built by an ancient race of Martians, the American space agency (Nasa) just wants to say: "look at this picture".

The image that started it

The latest images sent back from the orbiting Mars Global Surveyor (MGS), show, once again, that what is claimed by some to be a giant face is nothing more than a ruined mountain.

But space agency scientists know their work is in vain. Just as with previous pictures of the "Face", there are some that will dismiss this latest image as propaganda.

"What can you do?" one scientist told BBC News Online. "They're loonytunes."

'Illusion of eyes'

Twenty-five years ago something funny happened around Mars.

Seen from the side - no face

Nasa's Viking 1 spacecraft was circling the planet, snapping photos of possible landing sites for its sister ship Viking 2, when it spotted the shadowy likeness of a human face.

There it was - an enormous head nearly three kilometres (two miles) long that seemed to be staring back at the cameras from a region of the Red Planet called Cydonia.

A few days later, Nasa released the image under the caption "huge rock formation ... which resembles a human head ... formed by shadows giving the illusion of eyes, nose and mouth."

But some believed it really was a face, a deliberately built structure put up by some long-gone race of Martians. They even found other artificial structures on the plains of Cydonia left by the ancient civilisation.

Although no reputable scientist believed the Face was an alien artefact, photographing Cydonia became a priority for Nasa when Mars Global Surveyor (MGS) arrived at the Red Planet in September 1997.

Another look

"We felt this was important to taxpayers," explained Jim Garvin, chief scientist for Nasa Mars Exploration Program. "We photographed the Face as soon as we could get a good shot at it."

So on 5 April,1998, when MGS flew over Cydonia for the first time, scientists took a picture 10 times sharper than the original Viking photos...there was no face.

Did it convince everyone? Not a chance.

The Face on Mars is located at 41 degrees north Martian latitude where it was winter in April 1998 - 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 alien markings were hidden by haze.

"It's not easy to target Cydonia," said Dr Garvin. "In fact, it's hard work." MGS is a mapping spacecraft that normally looks straight down and scans the planet like a fax machine in narrow 2.5 km-wide (1.5 mile) strips. "We just don't pass over the Face very often."

...and another look

On 8 April, 2000, a cloudless summer day in Cydonia, MGS took its most recent peek: "We had to roll the spacecraft 25 degrees to centre the Face in the field of view," said Dr Garvin.

Said one observer: "Gee, it doesn't look like a face to me!"

Laser altimetry data from MGS is perhaps even more convincing than overhead photos in showing the Face to be natural.

Three-dimensional elevation maps show the formation from any angle. There are no eyes, no nose, and no mouth.

But sure as the planet is red, someone will not be able to face the facts.