An image of a mysterious shape on the surface of Mars, taken by the Nasa spacecraft ?Spirit?, has rekindled the debate about life on the Red Planet.

A magnified version of the picture, posted on the Internet, appears to some to show what resembles a human form among a crop of rocks. Where as some bloggers have discarded the image as a trick of light, others seem convinced that it is indeed evidence of an alien presence. The image is a recent Nasa posting of the ?Spirit?s? landing in 2004.

When the robotic rover set down on 24 January 2004, its images disappointed space-watchers, who were eagerly looking out for signs of extraterrestrial life. Now, they seem convinced that this image provides the evidence they have been so eagerly searching Nasa?s photo files for. The blown-up image indeed seems to resemble a figure striding among the Martian rocks.

Moreover, the Internet has been abuzz with postings offering theories. One said it was a? garden gnome, another even suggested that it was the? Virgin Mary. Another third suggested Bigfoot, the hairy bipedal mountain beast that appears in various guises in a number of legends around the world.

But the consensus seemed to be that it bore a striking resemblance to the Little Mermaid statue in the Danish capital, Copenhagen. Poster ?Madurobob? said it was a statue ?obviously built by an ancient civilisation that later departed Mars and settled in Denmark?.

Badastronomy.com tried to apply some perspective: ?A man? It?s a tiny rock only a few inches high. It?s only a few feet from the rover!?