Curiosity has been wandering about on the surface of the Red Planet since August 2012. That's nearly 3 years. In this time, it has found evidence of liquid water on Mars, discovered organic molecules, and suffered a bit of wear and tear.
Now, Curiosity has captured images of a fantastic blue sunset on this red world. Mission team members combined the images into a brief video of the Martian sunset. These images were captured with the rover's Mast Camera in-between dust storms on April 15, 2015. NASA officials said that these photographs record the first sunset Curiosity has observed in color on the Red Planet.
"The colors come from the fact that the very fine dust is the right size so that blue light penetrates the atmosphere slightly more efficiently," Mark Lemmon, a Curiosity team member from Texas A&M University, said in a NASA statement. "When the blue light scatters off the dust, it stays closer to the direction of the sun than light of other colors does. The rest of the sky is yellow to orange, as yellow and red light scatter all over the sky instead of being absorbed or staying close to the sun."
The planet gets its name from the dust that covers the surface. This gives the sky a red coloring during the day. You can see the contrast between the Martian sky during the day and during sunset in the image below.
Images captured from 2010 seem to show a similar sunset on the Martian horizon. These were captured using images from the panoramic camera (Pancam) on NASA's Mars Exploration Rover Opportunity.
NASA notes that, in the Curiosity image, the color has been calibrated and white-balanced to remove camera artifacts; however, they add that the Mastcam sees color in much the same way that the human eye does. So this view gives us a good idea of what a sunset would actually look like on the Red Planet. Though they note that the camera is a little less sensitive to blue than the human eye, so in reality, it would actually appear even bluer.