You can definitely see sunrises – and sunsets – from the moon’s surface. You just can’t see them as often as we see them from Earth.
Here on Earth, our planet’s rotation – or spin on its axis – carries us from daylight to darkness. That’s true on the moon as well. A lot of people incorrectly believe the moon doesn’t rotate, but indeed the moon does spin on its axis, just as Earth does. It has to in order to keep one face aimed in our direction.
But the moon’s spin is much slower than Earth’s. An earthly day last approximtely 24 hours. A lunar day lasts about one earthly month. As experienced from a single spot on the moon, there are 29 days from one lunar noon to the next. That means there would be about two weeks between each lunar sunrise and sunset, from any given spot on Earth’s globe.
Why isn’t there an eclipse at every full moon?
As seen from the moon, sunrise and sunset would seem much more abrupt than they are here on Earth. On Earth, when you watch a sunset, you can see colored light scattered by our planet’s atmosphere for a while after the sun disappears. But the moon doesn’t have an atmosphere. So if you were watching sunset on the moon, the moment after the sun set would be as dark as midnight – with no lingering color at all. And of course sunrise on the moon would come just as suddenly.
By the way, Earth’s atmosphere also makes our sky look blue. From the moon, the sky always looks black, even when the sun is shining in the lunar sky.
Thanks Qudratulah! Fun to imagine being on another world.
We should be able to download the picture on our cellphones.
You mean the pictures that accompany the posts on our site? Not sure if that’s possible given copyrights etc. We could ask our programmer … assuming that’s what you mean.
To my previous knowledge, moon completes a spin at its axis in the same time as does earth(24 hrs), and therefore we always see the same side of the moon.
Qudratulah, that’s not quite correct. The moon complete a spin on its axis in the same time the moon completes a single revolution around Earth in orbit. About a month for one lunar spin. About a month for one lunar orbit of Earth. That’s how the moon keeps a face toward Earth.
Meanwhile, Earth spins underneath the moon once every 24 hours.
You can prove to yourself that the moon must spin only once for each orbit of Earth, in order to keep the same face toward Earth. Place a chair in the middle of the room. Try to walk about it – as if the chair is the Earth, and you are the moon – with your face always toward the chair. You’ll see that your body has to make only one complete spin – with respect to the rest of the room – in the same amount of time you make one complete “orbit” around the chair, in order to keep your face toward the chair.
Good discussion! Thank you.
ES
The moon is in captured orbit. This means that it always keeps the same face towards the earth. Therefore the moon rotates once around its axis for every orbit it makes round the earth (otherwise if it kept the same face, say, towards the sun, we would see it appear to rotate as it orbited the earth).
As it rotates once for every orbit, its rotation time is 27.322 days – the same as a lunar ‘month’ – the time it takes to orbit the earth.
The moon has a diameter at the equator of 2160 miles and hence (from the formula Circumference = Pi x diameter) a circumference of 6785 miles. At the equator, then, it rotates this distance in 27.322 days or, (multiplying by 24 hours in a day), 655.728 hours.
Therefore its speed at the equator is 6785 miles in 655.728 hours, or 10.35 miles per hour. Obviously as you move away from the equator towards the poles this speed drops until, at the poles, it is zero.