Sunset
This is a close-up of the sunset on Sol 24. The red
sky in the background and the blue around the Sun are approximately as they would appear
to the human eye. The color of the Sun itself is not right -- the Sun was over exposed in
each of the 3 color images that were used to make this picture.The true color of the Sun
itself may be near white or slightly bluish.
This image of the Martian sunset from Sol 24 shows much more color variation than had previously been seen. The blue color near the Sun is not caused by clouds of water ice, but by the Martian dust itself. The dust in the atmosphere absorbs blue light, giving the sky its red color, but it also scatters some of the blue light into the area just around the Sun because of its size. The blue color only becomes apparent near sunrise and sunset, when the light has to pass through the largest amount of dust.
This image was taken by the Imager for Mars Pathfinder (IMP) about one minute after sunset on Mars on Sol 21. The prominent hills dubbed "Twin Peaks" form a dark silhouette at the horizon, while the setting sun casts a pink glow over the darkening sky. The image was taken as part of a twilight study which indicates how the brightness of the sky fades with time after sunset. Scientists found that the sky stays bright for up to two hours after sunset, indicating that Martian dust extends very high into the atmosphere.
Sol 24 sunset showing the sun sinking into the horizon.
(Left) False Color View of the Martian Sunset
(Right)Animation of the Martian sunset. This movie is made from nine images of the twilight following sunset over Ares Vallis. The images are enhanced in order to show the very subtle features in the haze, which are probably caused by layers that are slightly dustier than the surrounding air. The color is not the true color of the sunset -- that is shown in other images. At the beginning, the Sun is on the horizon just to the right of the frame, and it sinks during the next hour. At the time of the last image the sky is only 1% as bright as at the beginning, but the IMP can easily adapt to the darkness and return these pictures. Because there is so much dust extending high into the martian sky, the sky stays bright for more than an hour after sunset.