Astronomy Picture of the Day

Explanation: A dust storm on Mars can involve nearly the entire planet. As spring descended on the southern hemisphere of the red planet this June and July, a global dust storm raged. Pictured above is the storm on July 8 as it spread up from the south, oriented on the lower right. The image was captured by the robot Mars Global Surveyor spacecraft which continues to orbit the red planet. A smaller dust storm is visible in the north to the left of the dark giant volcano Ascraeus Mons. Far-reaching dust storms also occur on planet Earth.