Acid House smiley face found on Mars By Tom Chivers Last Updated: 11:01am GMT 04/02/2008 Astronomers have been having a funny time of it lately. We have had reports of Bigfoot (or possibly a Danish mermaid) on Mars, and a "spider" on the fiery planet of Mercury. You would be forgiven, therefore, for thinking the universe is laughing at us. And it turns out you'd be right. The Sun newspaper reports that a satellite orbiting Mars has now spotted what looks suspiciously like a big smiley face drawn crudely onto the surface of the red planet. The Mars smiley face (left) and the Acid House version (right)Disconcertingly reminiscent of the "acid house" faces worn by late-eighties ravers, the vast visage stares out from a crater, beaming a wonky-faced message of goodwill out in to the solar system. According to Mars experts, the image is not, in fact, a colossal and somewhat childish piece of interplanetary graffiti, but rather a chance geological formation caused by wind erosion and meteorite impact craters. Ten days ago Mars-watchers were baffled by what appeared to be the figure of Bigfoot, who had wandered some distance from his more usual roaming grounds in the American Rockies. However, there was also some debate among astronomers as to whether it was in fact the famous Little Mermaid of Copenhagen. Meanwhile Mercury was discovered to have a large geological anomaly of its own, in the form of a giant "spider" formation, believed to be unique in the solar system.