Posted by dannynic | Posted in General Science, Physics | Posted on 18-05-2008
Tags: AT4, moon, orbit, Physics, Sc4, space
Firstly, it’s had to google this without getting lots of hits for classic Pink Floyd albums. Secondly, strictly speaking it’s the *far* side of the moon. It’s not always dark because sometimes it is facing directly at the Sun and is well lit.
Anyway, the question relates to the fact that Moon always keeps the same face facing towards the Earth (and so the same face pointing away). This down to two important facts.
1. The moon rotates on its on axis, it takes approximately 28 days to make one full rotation
2. The moon orbits around the earth. It takes approximately 28 days to make one full orbit.
In the animation below, I have coloured the moon to make it clearer. This is the view from above as it rotates.
As the moon rotates, it is also travelling around the Earth. The Moon has become locked into a pattern – the time it takes to orbit the Earth is the same as the time it takes to make one full rotation – approximately 28 days.
As you can see, as the moon travels around the Earth, it is also rotating. The Red/Yellow face is always kept facing towards the Earth. If we were standing on the Earth looking at the Moon we would only see the Red/Yellow face. We would never be able to see the Blue/Green face.
Other Animations
http://www.edumedia-sciences.com/a213_l2-earth-moon-system-1.html
More Moon Information
