Mars Up Close - December 2007
Every 26 months, Mars and Earth have a close encounter. Earth travels around the Sun twice as fast as Mars and since both planets have an elliptical orbit, these encounters differ in distance each time. Hubble caught the red planet on one of these fly bys, when Mars was just 55 million miles away. This color image taken within 36 hours of the approach shows Mars free of any dust storms, but with noticeable cloud cover in both the Northern and Southern hemispheres.