The prestigious publication New Scientist magazine is reporting on controversial findings that open water was found on the surface of Mars two years ago. Open water should not be possible on Mars due to the harsh surface conditions, (though very strong photographic evidence has been found for occasional small flash floods) so if true, this is a real bombshell. Physicist and Lockheed engineer Ron Levin has looked at images returned several years ago by the Opportunity Rover while it was exploring a crater called Endurance. Creating stereoscopic reconstructions from paired images from the rover's twin cameras, he seems to have found some compelling evidence. The picture shows a one metre square area with a distinctly bluish tint, and indeed it looks just as you would imagine water would look if it were puddling in low depressions in the ground. It is also free of dust and other detritus, suggesting that if it is water or ice, it formed recently. Levin has previously theorised that water might exist briefly on the surface in a regular daily cycle, evaporating away as the day progresses. This however is a very contentious theory, as it would require some very precise circumstances to come about. It is worth mentioning that Levin's father Gilbert Levin was one of the scientists on the old Viking missions to Mars, which found no official evidence for life, though both father and son have been vigorous proponents of the idea that the scientific instruments on Viking did find life, but the results were incorrectly interpreted. I mention this because Levin may well have an axe to grind here, and just as conspiracy theorists are constantly finding signs of an ancient civilisation on Mars, this may be a case of the eye seeing what the mind wants it to see. However, it is equally fair to say that the picture is compelling, so here is hoping that NASA is open minded enough to take a look at this, and have Spirit and Opportunity keep their cameras trained for further examples. As Levin has pointed out, it only requires that they poke the surface with the Rover’s drilling tool to test out his theory. If it’s water, then the drill will make no visible impression. If it’s anything else, it will leave a mark.