Rotating question

[ben89]

ok was on the roof watchin the moon an i remember from my texbook that suposedly i can only see one side of the face of the moon eventho its twofaced is that right?<br /><br />now my question: how can i only see one side if the moons rotating? it is rotating corect?<br /><br />if its rotating then i see all its faces/ front, back, side, am i worng<br /><br />and if i"m on the moon do i only see one face of the earth too eventho it has a back?

 

[siarad]

The Moon circles the Earth at the same speed it rotates thus the same view is always to-wards Earth.<br />Think of a weight with a string through it spinning around.

 

[harmonicaman]

But everything isn't perfect. You can actually see more than half of the surface of the Moon from Earth because of a phenomenon called <b>Libration:</b><br /><br /><i>"Libration is a rocking movement of the Moon. Librations cause us to view the Moon from different angles at different times, enabling us to see about 59 percent of the Moon's surface from Earth, even though the same side always faces us. There are librations due to variations in the rate of the Moon's orbital motion (longitudinal libration) and to the inclination of the Moon's equator with respect to its orbital plane (latitudinal libration). There is also an apparent libration due to an observer on Earth viewing the Moon from different angles as the Earth rotates (diurnal libration, which occurs each day)."</i>

 

[ben89]

thank u to paster siarad / tho i dont get the weight-string-spinnin-thingy

 

[ben89]

i apreciate harmonicsmans help as always tho the libation thing is 2 advance 4 me<br /><br />what about on the moon is it the same way? do i see only 59% of the earth to?

 

[harmonicaman]

From the side of the moon facing the Earth, you would get to see all of the Earth over time!

 

[ben89]

2 harmonicaman hows that posible if on earth i could only see 59$ of the moon/ so why aint it the same on the moon? why all of asudden its 100% on the moon?

 

[harmonicaman]

Moon - Earth tidal lock webpage. <br /><br />We can only observe 59% of the surface of the Moon from the Earth because it always has the same side pointed towards us. The Moon gets to see the whole Earth because the Earth is constantly rotating from the Moon's viewpoint.

 

[ben89]

thank u to shuttle-guy 4 the encoragement/ hes superguy in my book/hes been there where i wanna go basiclly

 

[ben89]

my thank u gos 2 harmonicaman once again 4 being a good teacher 2 me

 

[rfoshaug]

Here's a bit of an explanation for you (it works best if you live on the northern hemisphere of the Earth. If you live south of the Equator, "left" and "right" is swapped since you're then "upside down". <img src="/images/icons/wink.gif" /><br /><br /><br />Watching the Moon from Earth is a bit like watching a very slow NASCAR driving on an oval track. If you instead of sitting in the grandstands was sitting in the middle of the track (so you could see the track around you on all sides), you'd see the left side of the car as the car goes around the track.<br /><br />Since the track isn't a perfect circle but some kind of oval track (or an ellipse in the case of the Moon's track around Earth), you would sometimes see more of the front of the car, and at other times you'd see the rear of the car as it went down the backstraight before entering the next turn. But you'd never get to see the right side of the car from that position. It's the same with the Moon, sometimes we see more of one side, sometimes more of the other. The "front" of the Moon is what we see as the left side, since it moves to the left compared with the background stars.<br /><br />So why does the moon rise in the east and move to the <i>right</i> on the sky then? That is because Earth is spinning faster than it takes the Moon to do one orbit (one lap around the track). If we look at our NASCAR analogy, that would be like you were spinning to the left. Even though the cars really move to the left, they seem to move to the right because you're spinning so fast to the left.<br /><br />So at one moment you see a car crossing the start/finish line to your left, but as you turn, you can see the start/finish line and the car straight ahead of you (the car will by now have crossed the start/finish line but will not have gotten very far). Seen from you the car was at your left but is now straight ahead, so it seems like it has moved to the right. But when you know that the background grandstands (or in the case of the <div class="Discussion_UserSignature"> <p><font color="#ff9900">----------------------------------</font></p><p><font color="#ff9900">My minds have many opinions</font></p> </div>

 

[ben89]

my thank u goes 2 rfoshaug 4 this beutiful and pictureresqe explaination. i"m very very very grateful.<br /><br />i learn more here than i do from my texbook and somtimes from class/