A sunset in color…
Take a good look at this image, let it soak in. This is more than just a simple sunset, this is what a sunset looks like on Mars. Yep, on Mars. Slightly different than the reddish sunsets we are used to on Earth.
NASA’s Curiosity Mars rover recorded this view of the sun setting at Gale Crater on the April 15, which marked the 956th Martian day, or sol. This series of images, composed as an animation, is the first time Curiosity observed a Martian sunset in color. The images were captured by Curiosity’s Mastcam, which “sees” color very similar to the way we do, although it is slightly less sensitive to blue light.
So why does the sunset appear blue? The Martian atmosphere contains very fine particles that allow blue light to penetrate the atmosphere better than longer wavelengths (like red). As a result blue colors tend to stay in the sky and red/yellow scatter more easily. This effect is more easily seen at sunset when light from the sun passes through a longer path in the atmosphere than it does at mid-day.
“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,” said Mark Lemmon of Texas A&M University, College Station, the Curiosity science-team member who planned the observations. “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.”
Sunsets tend to feature more dramatic colors here on Earth; however, Martian sunsets tend to showcase mainly blue light, with more reddish/rust colors during the day.This sunset is more than a pretty picture, as sunset observations will tell scientists more about the vertical distribution of dust in Mars’ atmosphere.
Image & Source Credit: NASA/JPL-Caltech