Cool animation of the Moon

[radarredux]

I've always wondered if the view of the Moon varies over time. The second link below show an animation of the Moon over 28 days. It is quite eye opening.<br /><br />http://srspacemonkey.blogspot.com/2007/01/moon-over-28-days.html<br />http://bp1.blogger.com/_h0ptpX-4ncM/RcX4IhSAfKI/AAAAAAAAAA8/1AjQ8LkBlT0/s1600-h/Lunar_libration_with_phase2.gif

 

[bpfeifer]

Very Cool animation. I think Galileo was the first to record noticing this effect. <div class="Discussion_UserSignature"> Brian J. Pfeifer http://sabletower.wordpress.com<br /> The Dogsoldier Codex http://www.lulu.com/sabletower<br /> </div>

 

[willpittenger]

You can see the Moon swinging back and forth. I assume that is due the the rotation being out-of-synch with its orbit and its off-center of gravity. <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>

 

[MeteorWayne]

I haven't been able to get the animation to work yet.<br />Probably swamped with hits from SDC <img src="/images/icons/smile.gif" /> <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[strandedonearth]

While I also wasn't able to view the animation in the original poster's link, it's probably the same thing as this APOD.

 

[MeteorWayne]

Oh, that is superb!! <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[radarredux]

> <i><font color="yellow">it's probably the same thing as this APOD.</font>/i><br /><br />The APOD animatation is so fast it makes me nauseous watching it.</i>

 

[bonzelite]

WOW!! <br /><br />what is this effect created by?! i'll never see the moon the same!! <br /><br />man that is so damn neat!

 

[tony873004]

It's caused because of the Moon's elliptical orbit. Once per lunar orbit, the Moon reaches perigee, its closest point to Earth. And once per lunar orbit it reaches apogee, its furthest point from Earth in its orbit. Apogee and Perigee are spaced about 14 days apart. So over the entire lunar orbit, you get to watch the Moon grow small, then big, then back to small.<br /><br />Since the Moon's rotational period is the same as its orbital period, it always presents the same face to Earth... well, almost. When the Moon is closest to Earth, it is moving faster in its orbit than when it is furthest from Earth. But the Moon's rotational period does not speed up or slow down. It stays constant (ignore timeperiods of millions of years). So its rotational period gets a little out of sync with its orbital period, hence the back and forth wobble. But once per orbital period they sync back again.

 

[bonzelite]

thank you, tony, for that clear explanation. i have vaguely known about that --and i emphasize vaguely-- but this just drives the point home. to actually see it is just stunning and shocking!