Did You Know?

 On Mars, sunsets are blue.

The sunset pictured here may look strange to you and me, but on Mars it's a rather common sight. A bluish hue radiates outward from the setting Sun, fading gradually before taking on a pinkish tinge.

Strangely enough, that's more or less the exact opposite of what you'd expect to see during sunsets here on Earth, which tend to fade from warm, ruddy colors into the bluish purples typical of a late afternoon sky.

According to the Curiosity science-team member Mark Lemmon from Texas A&M University, College Station, 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. 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.

Just as colors are made more dramatic in sunsets on Earth, Martian sunsets make the blue near the sun's part of the sky much more prominent, while normal daylight makes the rusty color of the dust more prominent.

Source: NASA