The images, taken by Nasa's Mars Explorer Spirit, seem to show a figure striding purposefully across the surface of the planet.

However the more sceptical have decided that it is just a rock.

Share your views by commenting below or email the editor at eteditor@peterboroughtoday.co.uk

At first astronomers were disappointed with pictures sent back from the surface of the Red Planet by the six-wheel robot four years ago.

But a space fan spotted the figure, which was just a pinprick in the original photograph. It was blown up and posted on a website.

One stargazer writes on the site: "My first thought - it's Big Foot! If you show me another rock in another photo from Mars or Earth that naturally looks like that, I will reconsider."

Another said: "I couldn't believe my eyes when I looked and saw what appears to be a naked alien running around on Mars."

Experts say that if the planet once had surface water, there was the potential to support life.

Analysis of soil showed it contained 90% silica - a concentration only likely to have formed when water is present.

But as to whether there are likely to be aliens moving around, opinion is clearly divided...