This is what a Martian sunset looks like

Every evening, when the sun sets on Mars, this is what the Opportunity rover — one of two active rovers on the planet — sees:

You may be wondering about the one big difference between this sunset and those on Earth.
 Why is everything so blue?
 As it turns out, it's an effect of Mars' dust. Airborne dust particles disproportionately scatter red and green wavelengths of light, so that mostly blue light reaches the surface. On Earth, gas molecules in our atmosphere disproportionately scatter blue light, so more red light reaches our eyes. via