Why the moon keeps the same side toward earth?

"Uncle Al" wrote in message
...
junhwi wrote:
Why the moon keeps the same side toward earth?
Can we prove that mathemathically?
And, for same relation - sun and earth - , after so many
years.. the earth may toward same side to the sun?


0 "Sam Wormley" wrote in message
0 ...
0 Ref: http://imagine.gsfc.nasa.gov/docs/as...s/980218b.html
0 Most of the satellites in the solar system rotate synchronously like
0 our moon (see http://www.seds.org/nineplanets/nineplanets/luna.html).
0 An example of one that doesn't is Saturn's moon Hyperion. Its rotation
0 is actually chaotic. You can find out more about it at
0 http://www.seds.org/nineplanets/nine.../hyperion.html
0 Also, http://www.solarviews.com/eng/data1.htm#orb
0 which is a table of orbital and rotation periods, among other things.
0 Damian Audley and John Cannizzo
0 for Ask a High-Energy Astronomer


Uncle Al wrote in
message ...
1) Lunar orbital locking.
2) Lunar libration.
Google
"lunar libration" 754 hits
3) Why do you think the side of the moon facing the Earth
is all smooth (less cratering after the fact), and the side of
the moon facing away from the Earth is nothing but violently
craggy topography?
The Earth-Sun system does not embrace Earth-moon orbital
conditionsfor obvious reasons.

John Morriss wrote:
I've read that one reason is that the Earth-facing-hemisphere gets one
or two lunar eclipses a year. That increases the thermal cycling and
attendant thermal erosion by over 8%; and the thermal cycling from an
eclipse is more abrupt than that from a lunar sunrise/sunset...
Any meteorites hitting the Earth-side would have to make a loop around
the moon, or skim past the earth. Calculating the magnitude of this
effect is certainly beyond me...


When the moon was semi-molten, all the low mp anorthosite sloshed to
the front side down the gravity divergence. The backside then was all
spikes and dikes of residual high melting stuff already solidified.
The anisotropy amplifies the orbital locking.
Uncle Al


The Earth/Moon system affects each others body's the tidal sizes of
molten core, solid mantle, liquid waters and atmosphere (whichever
is applicable) in extremely complicated ways when viewed in detail.
(even human behavior....so most Sheriffs do attest to. :-) )

What I am interested to hear is whether/which/how the moon's "facing"
and orbits period was affected/changed when according to the latest
theory ALL the oceans waters froze, preventing tides from forming,
and the other extreme case when there was no ice at all and only
one single super-continent as an "island" in one global ocean?

Did the moon "shake" its face more, then less, back to a fixed "stare"
during these extremes and did the moon's orbit distance increase and
decrease? Do we expect a long term, irreversible dampening of these
effects or do we have a system which can oscillate within the same
amplitudes "forever", well, for a few billion years, without loosing
a sizable portion of energy ?
hanson

Dear hanson:

"hanson" wrote in message
hlink.net...
....
What I am interested to hear is whether/which/how the moon's "facing"
and orbits period was affected/changed when according to the latest
theory ALL the oceans waters froze, preventing tides from forming,
and the other extreme case when there was no ice at all and only
one single super-continent as an "island" in one global ocean?

There was a reduced recession rate during the "ice ages" as witnessed in
tidal rhythmites.

Did the moon "shake" its face more, then less, back to a fixed "stare"
during these extremes and did the moon's orbit distance increase and
decrease? Do we expect a long term, irreversible dampening of these
effects or do we have a system which can oscillate within the same
amplitudes "forever", well, for a few billion years, without loosing
a sizable portion of energy ?

I would expect that this oscillation would also be dampened. But the
coupling would be really weak. And additional "braking" is constantly
applied, since the Moon's period is always getting longer.

David A. Smith

Why the moon keeps the same side toward earth.

Do we live in a world so filled with knowledge that only a few will take the
time to think?

The tides tell us that the moon encircles the earth every day relevant to a
stationary observer.

To clearly describe any motion it should be desired that the observer be
stationary.

The moon makes one revolution on its axis every 27 days, 7 hours and 11
seconds so the same side will face the sun during a one day period.

Therefore the moon's daily travel at 60,000 miles per hour around the earth,
to create the tides, will show all of its lunar surface to us earthlings
every 23 hours. Or in the alternative every 25 hours depending on the
direction of the rotation on it's axis.

Food for thought?

Ken McKenzie
www.starapex.com

(formerly)" dlzc1.cox@net wrote in message
newshTyb.25243$Bk1.22951@fed1read05...
Dear hanson:

"hanson" wrote in message
hlink.net...
...
What I am interested to hear is whether/which/how the moon's "facing"
and orbits period was affected/changed when according to the latest
theory ALL the oceans waters froze, preventing tides from forming,
and the other extreme case when there was no ice at all and only
one single super-continent as an "island" in one global ocean?

There was a reduced recession rate during the "ice ages" as witnessed in
tidal rhythmites.

Did the moon "shake" its face more, then less, back to a fixed "stare"
during these extremes and did the moon's orbit distance increase and
decrease? Do we expect a long term, irreversible dampening of these
effects or do we have a system which can oscillate within the same
amplitudes "forever", well, for a few billion years, without loosing
a sizable portion of energy ?

I would expect that this oscillation would also be dampened. But the
coupling would be really weak. And additional "braking" is constantly
applied, since the Moon's period is always getting longer.

David A. Smith

"Kenneth McKenzie" wrote in message
news:xxdAb.572798$pl3.68851@pd7tw3no...
Why the moon keeps the same side toward earth.

Snip

Don't top post.

Dear Kenneth McKenzie:
"Kenneth McKenzie" wrote in message
news:xxdAb.572798$pl3.68851@pd7tw3no...
Why the moon keeps the same side toward earth.

Do we live in a world so filled with knowledge that only a few will take
the
time to think?

Did you?

The tides tell us that the moon encircles the earth every day relevant to
a
stationary observer.

To clearly describe any motion it should be desired that the observer be
stationary.

It depends on the observatiion one would make...

The moon makes one revolution on its axis every 27 days, 7 hours and 11
seconds so the same side will face the sun during a one day period.

"So" in this context implies a will...
And the "same face" isn't fully exposed to the Sun, as 1/27th or so has
slid around to the dark side, and 1/27th has come into the light. From
morning of one Earth day to the morning of the next.

Therefore the moon's daily travel at 60,000 miles per hour around the
earth,
to create the tides, will show all of its lunar surface to us earthlings
every 23 hours. Or in the alternative every 25 hours depending on the
direction of the rotation on it's axis.

The Moon is tidally locked to the Earth, such that its period of rotation
matches its orbital period. This means that everyone on Earth sees the
same craters every night of the month that they are lit. We didn't see the
back side until we flew satellites and manned missions around the Moon.

Food for thought?

Please do.

David A. Smith

(formerly)" dlzc1.cox@net wrote in message
news:OkmAb.27817$Bk1.21839@fed1read05...
Dear Kenneth McKenzie:
"Kenneth McKenzie" wrote in message
news:xxdAb.572798$pl3.68851@pd7tw3no...
Why the moon keeps the same side toward earth.

Do we live in a world so filled with knowledge that only a few will take
the
time to think?

Did you?

The tides tell us that the moon encircles the earth every day relevant
to
a
stationary observer.

To clearly describe any motion it should be desired that the observer be
stationary.

It depends on the observatiion one would make...

The moon makes one revolution on its axis every 27 days, 7 hours and 11
seconds so the same side will face the sun during a one day period.

"So" in this context implies a will...
And the "same face" isn't fully exposed to the Sun, as 1/27th or so has
slid around to the dark side, and 1/27th has come into the light. From
morning of one Earth day to the morning of the next.

Therefore the moon's daily travel at 60,000 miles per hour around the
earth,
to create the tides, will show all of its lunar surface to us earthlings
every 23 hours. Or in the alternative every 25 hours depending on the
direction of the rotation on it's axis.

The Moon is tidally locked to the Earth, such that its period of rotation
matches its orbital period. This means that everyone on Earth sees the
same craters every night of the month that they are lit. We didn't see
the
back side until we flew satellites and manned missions around the Moon.

Food for thought?

Please do.

David A. Smith



You do realize that he and smart both thought that
the OP meant that the moon always had the same
side always facing earth not that the Face we can observe
lighted is always the same . Give a bit of insight into
information processing... of the human mind...

In sci.physics, Kenneth McKenzie

wrote
on Sat, 06 Dec 2003 05:10:53 GMT
xxdAb.572798$pl3.68851@pd7tw3no:
Why the moon keeps the same side toward earth.

Do we live in a world so filled with knowledge that only
a few will take the time to think?

The tides tell us that the moon encircles the earth every
day relevant to a stationary observer.

Relative to an observer *on Earth* you mean. The Earth
isn't all that stationary anyway, as it turns out; even if
one hypothesizes an absolute inertial coordinate system
where the Earth is absolutely motionless on midnight GMT
December 1, relative to this same coordinate system on
midnight GMT June 1 the Earth will be whizzing at the
speed of about 60 km/s.

That's not counting the Sun's motion within the Milky Way,
which might be called a wobbly circle. The exact speed
is not clear but is probably around 250 km/s, relative
to the galactic center. I have no idea how fast the Milky
Way galaxy is moving to other things, either.

As it is, the Moon doesn't quite keep the same face towards
Earth, as the Moon's orbit isn't exactly circular, leading
to some libration.


To clearly describe any motion it should be desired that the
observer be stationary.

The moon makes one revolution on its axis every 27 days,
7 hours and 11 seconds so the same side will face the sun
during a one day period.

I think you're confused. The moon has monthly phases
(roughly); this means that the same side is not facing
the Sun. Were it the case that the same side were facing
the Sun, the Moon would be turning relative to the Earth,
which is clearly not the case as one can observe readily
by looking at the Moon each night; the "Man In The Moon"
is always visible during a full or gibbous moon and even
during the quarters one might see part thereof.


Therefore the moon's daily travel at 60,000 miles per hour
around the earth, to create the tides, will show all of its
lunar surface to us earthlings every 23 hours. Or in the
alternative every 25 hours depending on the
direction of the rotation on it's axis.

Not quite. It will show all of its lunar surface to someone
*out in the stars* every 27 days or so.


Food for thought?

Needs salt. :-)

[rest snipped]

--
#191,
It's still legal to go .sigless.

Dear Paul R. Mays:

"Paul R. Mays" wrote in message
...

(formerly)" dlzc1.cox@net wrote in message
news:OkmAb.27817$Bk1.21839@fed1read05...
....
The moon makes one revolution on its axis every 27 days, 7 hours and
11
seconds so the same side will face the sun during a one day period.
....
You do realize that he and smart both thought that
the OP meant that the moon always had the same
side always facing earth not that the Face we can observe
lighted is always the same . Give a bit of insight into
information processing... of the human mind...

The english language is such a whore, sometimes it is hard to tell what is
being said. The sentence I left in above is a case in point.

The OP, based on the title *knew* the side facing the Earth was the same.
Yet the sentence above sounds like the responder believed the Moon was
tidally locked to the Sun. Your first sentence appears for all the world
to say the same thing twice...

David A. Smith