Sunset on Mars

This image was taken by NASA's Mars Exploration Rover Spirit on May 19, 2005. This spectacular view is of the sun setting on Mars as it sings below thee rim of the Gusev crater. It was taken at around 6.07 in the evening on the 489th day Spirit was on Mars. "Sunset and twilight images are occasionally acquired by the science team to determine how high into the atmosphere the Martian dust extends, and to look for dust or ice clouds. Other images have shown that the twilight glow remains visible, but increasingly fainter, for up to two hours before sunrise or after sunset. The long Martian twilight (compared to Earth's) is caused by sunlight scattered around to the night side of the planet by abundant high altitude dust. Similar long twilights or extra-colorful sunrises and sunsets sometimes occur on Earth when tiny dust grains that are erupted from powerful volcanoes scatter light high in the atmosphere." -NASA, http://www.nasa.gov/multimedia/imagegallery/image_feature_347.html