Theories include collapsed soil, earthquakes, or 'Martian art'
                                
                                
                                    (Newser) -
                                    Gary Dalton was draining the irrigation pond on his farmland in Circleville, Utah, when he made a startling discovery: a giant crater staring back up at him from the bottom of the basin. "The sun was just right, so I saw this blasted thing that no one had ever...