Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: John Gillard on 15/06/2008 23:05:06

Title: Does the moon rotate on its own axis?
Post by: John Gillard on 15/06/2008 23:05:06

John Gillard asked the Naked Scientists:

Why is it claimed by most astronomers that the Moon
rotates on its own axis ?. It obviously does not.

What do you think?

Title: Does the moon rotate on its own axis?
Post by: lyner on 15/06/2008 23:13:24

Hello John
How does it obviously not, if it goes round us once a month and is always facing us? Try walking round a table, facing it all the time, without 'turning on your own axis'. If you don't turn, you won't be facing the table all the time.

Title: Does the moon rotate on its own axis?
Post by: blakestyger on 16/06/2008 13:47:52

That's right - but the big mystery is how it rotates such that it always shows the same aspect.
Was it always thus or a function of its present distance from us - as the moon is slowly moving further away from Earth will future observers be able to see some of 'the other side'?

Title: Does the moon rotate on its own axis?
Post by: LeeE on 16/06/2008 15:13:55

The Moon always shows the same aspect because it's tidally locked to the Earth - http://en.wikipedia.org/wiki/Tidal_locking (http://en.wikipedia.org/wiki/Tidal_locking)

This won't change as it moves further away, at least while it's still under the influence of Earth's gravity.  That is, while it continues to orbit the Earth.