Moon Question

Does the same side of the moon always face the earth, or does the moon
rotate and spin around like the earth?

Are the classroom models which have the moon stuck on a pole which
doesn't spin inaccurate? The craters on the side of the moon that
faces earth during a full moon are different from what I can tell.

I've looked at a bunch of pictures and the craters aren't in the
exact same position in each of them.

Denny Jenkins wrote:
Does the same side of the moon always face the earth, or does the moon
rotate and spin around like the earth?

Yep, you didn't know this already? It rotates like the Earth, but
coincidentally, it takes the same period of time for one rotation,
as it takes for one orbit around the Earth, which is why we always
see the same side.

-----
Kill ratio of Palestinian children to Israeli children 5.7-to-1,
Israel's favor.
Kill ratio of all Palestinians to Israelis: over 3-to-1.
---------
http://www.lrb.co.uk/v28/n06/print/mear01_.html
----------
"Don't worry about American pressure on Israel. We,
the Jewish people, control America, and the Americans know it."
---Israeli Prime Minister Ariel Sharon, 2001
--
Cliff

wrote in alt.astronomy

Denny Jenkins wrote:

Does the same side of the moon always face the earth, or does the moon
rotate and spin around like the earth?

Yep, you didn't know this already? It rotates like the Earth, but
coincidentally, it takes the same period of time for one rotation,
as it takes for one orbit around the Earth, which is why we always
see the same side.

But we don't always see the same side, since the pictures of the
full moons I looked at are different.

Denny Jenkins wrote:
wrote in alt.astronomy


Denny Jenkins wrote:


Does the same side of the moon always face the earth, or does the moon
rotate and spin around like the earth?


Yep, you didn't know this already? It rotates like the Earth, but
coincidentally, it takes the same period of time for one rotation,
as it takes for one orbit around the Earth, which is why we always
see the same side.


But we don't always see the same side, since the pictures of the
full moons I looked at are different.


Make sure the images you are looking at are Earth-based. All of the
Earth-based models of the Moon will show pretty much the same
configuration of light and dark areas, what is colloquially referred to
as the "Man in the Moon". As Mr. Reeling mentions, the Moon is
gravitationally locked in a synchronous orbit about the Earth, with one
rotation period the same as one orbital period (in fact, if the Moon did
not spin, we would be able to see all of its surface over time). This
situation of synchronous orbits is quite common among the other planets
and many of their natural satellites, and for the same reason.

Denny the Moon rotates 27.32 Earth days,and orbits in 27.32 Earth days
Thus the moon keeps the same face turned towards the Earth at all times
Bert

In article ,
Denny Jenkins wrote:

Does the same side of the moon always face the earth, or does the moon
rotate and spin around like the earth?

Yes.

Seriously, the Moon does rotate on its axis, but due to a phenomenon
called "tidal locking" its rotational period is exactly the same as its
period of revolution, the time it takes to orbit the Earth. As a result
it always shows us the same face and, conversely, from a given location
on the Moon the Earth will always be seen in just about the same place
in the sky.

Are the classroom models which have the moon stuck on a pole which
doesn't spin inaccurate? The craters on the side of the moon that
faces earth during a full moon are different from what I can tell.

Some of the Full Moon's features appear changed in comparison to the
partial phases, because sunlight is then being reflected directly back
at us, while at other times the illumination is more oblique. For one
thing, where there's surface relief there'll be shadows that vary in
length according to the local altitude of the Sun. For another, various
surface materials and textures can change in appearance as their
light-source moves as an effect of selective absorption or scattering.
The enormous "ray systems" that surround some of the larger craters, for
example, are most apparent within a day or two of a Full Moon.

I've looked at a bunch of pictures and the craters aren't in the
exact same position in each of them.

As someone else suggested, make sure they were all taken from Earth!

However, since the Moon's orbit isn't perfectly circular, its position
isn't perfectly in synch with its rotation all the way around--it just
averages out that way. So it does appear to rock back and forth over the
course of a month (the technical term for the motion is "libration"),
exposing a little more of the leading limb and less of the trailing at
one time, and the converse around two weeks later. The difference
between the views is not great, but it's certainly enough for the
observant to notice in photos, as you apparently have done, and for
moon-watchers to take into account when planning observing sessions.
Moreover the tilt of the Equator WRT the plane of the Moon's orbit lets
us see a little more of the north limb at some times, the south limb at
others. Finally there's parallax to consider: observers in the Arctic
(or Antarctic), and observations made near moonrise (or moonset), will
have a slightly different angle of view from those at the Equator, and
when the Moon is at its highest, respectlvely.

There's still something like 45% (?) of the Moon's surface that we never
even glimpse from Earth, and that deserves the designation "the far side
of the Moon".

--
Odysseus

(G=EMC^2 Glazier) wrote in alt.astronomy

Denny the Moon rotates 27.32 Earth days,and orbits in 27.32 Earth days
Thus the moon keeps the same face turned towards the Earth at all times

It hasn't always been exactly like that and will change over time
though, right? I read that the moon is moving away from earth, so
after a few more million years, its orbit around earth will be further
out so take longer, right?

In article ,
Denny Jenkins wrote:

(G=EMC^2 Glazier) wrote in alt.astronomy

Denny the Moon rotates 27.32 Earth days,and orbits in 27.32 Earth days
Thus the moon keeps the same face turned towards the Earth at all times

It hasn't always been exactly like that and will change over time
though, right? I read that the moon is moving away from earth, so
after a few more million years, its orbit around earth will be further
out so take longer, right?

Yes, but it will still be tidally locked: however long the month
becomes, the lunar day will lengthen to match.

--
Odysseus

Denny what you say could be very right/(why not? They claim the Moon
once was 25,000 miles from Earth(I think 50,000) so you can see its
orbit has been getting bigger and bigger. I have a theory based on
good science that this is true of all orbiting objects. bert

Good science? No, total BULL****, BEERTbrain!

Saul Levy


On Sat, 22 Jul 2006 13:24:27 -0400, (G=EMC^2
Glazier) wrote:

Denny what you say could be very right/(why not? They claim the Moon
once was 25,000 miles from Earth(I think 50,000) so you can see its
orbit has been getting bigger and bigger. I have a theory based on
good science that this is true of all orbiting objects. bert