Astronomy Picture of the Day . A Dust Devil Swirling on Mars . ... Credit: Mars Exploration Rover Mission , JPL , NASA Explanation: What is that wisp on the horizon? Scientists think that the slight white apparition is actually a Martian dust devil that was caught swirling across Mars . The above image was taken earlier this month by the robotic rover Spirit . ... The most similar phenomena to Martian dust devils on Earth are tornadoes and waterspouts . ... Victoria Crater on Mars . ...