Mars' atmosphere is much thinner than Earth's, and also extremely dusty. The particles suspended in Mars' atmosphere are large and rich in iron oxide, which absorbs light with shorter wavelengths. That's why the planet's sky usually ranges from reddish to dark yellowish-brown in photographs taken by NASA's rovers at different Martian locations.
A day on Mars lasts 24 hours and 37 minutes—less than an hour longer than Earth's—which means sunrises and sunsets on the Red Planet follow the same rhythm as the ones here on our Blue Marble. However, because the Sun is farther from Mars than Earth—about 142 million miles (229 million km), compared to Earth's 93 million miles (150 million km)—the Sun looks only about two-thirds as big as it does on Earth, and its sunlight is less intense. Thus, as red light scatters across the sky during Martian sunsets, dust particles in the direction of the Sun scatter blue light, giving it a bluish glow.
