Re: What colour is the sky on the moon and are there sunsets on the moon?

hi Nicole,

Maybe we should start this answer by asking "why is the sky blue and the sunset red on the earth?" The short answer is - because of the atmosphere. Particles and molecules in the air scatter light from the sun in all directions. Blue light scatters the most (it has the shortest wavelength), so blue light reaches our eyes from all directions and we see a blue sky. At sunset, we look at the sun through a thicker layer of air than if it were overhead. Then, the short wavelength light is scattered so much that hardly any of it reaches our eyes - we see only the longer wavelength orange and red.

This is all explained very nicely at why is the sky blue?

The moon has no atmosphere - there is no air to scatter light from the sun. On the moon, you would see a brilliant white sun against a black sky. There are lots of images showing the lunar sky from the manned moon landings - a good place to look for them is the Apollo Lunar Surface Journal Image Library.

Are there sunsets on the moon? Well, the sun does set - the moon rotates like the earth and so the sun gradually moves through the sky and sinks beneath the horizon. However without air, the colour does not change to red. The moon also turns on its axis in the same time as it takes to orbit the earth - about every 28 days, which is why we only see one side of the moon. This means that if you stood on the moon, sunrise to "midday" would take about a week, then "midday" to sunset about another week, then there would be 2 weeks of night!