Erecting a three-metre-high monolith on a soundstage in London is one thing, copying the exercise in a sandstone canyon in the Utah desert is another but when a giant plinth shows up on a Martian moon it’s hardly surprising that people start scratching their heads.

Ever since the release of movie-icon Stanley Kubrick’s 1968 masterpiece, 2001: A Space Odyssey, monoliths have become synonymous with the presence of extraterrestrial intelligence so when one appeared in Mars Global Surveyor images of Phobos it certainly got tongues wagging.

Adding to the mystery was another feature captured by the Mars Reconnaissance Orbiter on the surface of the red planet itself. According to scientists at the University of Arizona, this object is projected out of the Martian surface and appears to be perfectly rectangular.... FULL STORY