Q: CAN you tell me anything about the human face that appears in the rocks on the planet Mars? I have seen photographs of this and I would like to know the theory of its origin. - J Anderson, Houghton-le-Spring.

A: THE 1976 Viking 2 Space Probe mission to Mars sent back to earth dozens of photographs of the surface of Mars. One photograph aroused much public interest. It showed a rock about one mile wide and 1,500 feet high within a flat area of Mars called Cydonia Plain. The rock, or hill, appeared to have a remarkable similarity to a human face.

It was dismissed by NASA as a quirk of shadows and light, caused by the sun shining at a low angle. Most scientists and astronomers agree with this explanation. However, a small number of people believe "the face" is proof that there was once an alien civilisation on Mars who constructed the face to send a message to earth.

In 1993, the space mission of Mars Observer was expected to set the record straight. Unfortunately, the Mars Observer craft failed and, due to technical problems, it was unable to photograph the Martian surface. Conspiracy theorists believed that NASA had succeeded in taking photographs of the Cydonia region, but were, for some reason, hiding the results.

A further mission to Mars by the Mars Global Surveyor was successful in capturing images of the Cydonia region in 1998. This time the image was seen without shadows under a different angle of sunlight using much higher resolution images than were possible in 1976. The relief feature could be seen much more clearly and appeared as an obscure and not particularly impressive rock formation.

NASA hoped that this would settle the matter, but some of the Mars-Face enthusiasts insisted that this was also a cover up and that NASA had manipulated changes to hide the truth.

The enthusiasts have other theories about the rock and have noted that the face resembles that of the Egyptian sphinx. Some people have even suggested that a collection of rocks near the face resemble pyramids and one man has even plotted the outline of an abandoned Martian city.

Having seen the 1976 face photograph (which can be found on numerous Internet sites), it is remarkably similar to a human face. The photographs of 1998 are much brighter, much sharper and in no way at all resemble a human face.

IS IT now compulsory to have a driving licence with your photograph on it? - J Hobson, Newton Aycliffe.

MODERN driving licences now come in two parts - a photocard and a paper counterpart licence. The photocard contains a computerised photograph of the driver and a computerised miniature copy of their signature. The paper counterpart includes details of endorsements. Legally the two parts of the licence should be kept together. Anyone who needs to renew their old style licence must also apply for a photo licence by completing the DVLC forms D750 and D1.

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