Explanation: If you could stand on Mars -- what might you see? The Opportunity Rover has captured just that.The distant red horizon is so flat and featureless that it appears similar to the horizon toward a calm blue ocean on Earth. Clouds on Mars can be composed of either carbon dioxide ice or water ice, and can move quickly, like clouds move on Earth.
What a wonderful shot! A priceless picture made possible by the ever expanding limits of science.