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Anonymous
Anonymous asked in Science & MathematicsAstronomy & Space · 1 decade ago

Why do we always see the same side of the moon?

a. It's coincidence that the moons rotational period and revolutional period are the same

b. the moon lost its extra rotational energy due to tidal forces long ago

c. the moon was most-likely created from the earth (by asteroid impact) and this syncronized its orbit

d. the moon looks the same all the way around

13 Answers

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  • Flavio
    Lv 4
    1 decade ago
    Favorite Answer

    The correct answer is (b).

    It's a generic phenomenon, called tidal locking, which occurs every time two celestial bodies can exchange mechanical energy through tides.

    Besides Moon-Earth, there are many other examples, such as Mercury-Sun (see following link).

  • 1 decade ago

    The Moon is in synchronous rotation, meaning that it keeps nearly the same face turned away from Earth at all times. Early in the Moon's history, its rotation slowed and became locked in this configuration as a result of frictional effects associated with tidal deformations caused by the Earth.[3] Nevertheless, small variations resulting from the eccentricity of the lunar orbit termed librations allow up to about 59% of the lunar surface to be visible from Earth.[1]

    The side of the Moon that faces Earth is called the near side, and the opposite side is called the far side. The far side should not be confused with the dark side, which is the hemisphere that is not being illuminated by the Sun at a given moment. The far side of the Moon was first photographed by the Soviet probe Luna 3 in 1959. One distinguishing feature of the far side is its almost complete lack of maria.

  • Anonymous
    1 decade ago

    a),b) No its not, its a law in physics that two objects spinning around other, are loosing energy, in this case their angular momentum. So After both the moon and the earth have lost mutch of ther angular momentum, the moon stoped rotating, and the earth rotates with the speed it does now.

    c) There is a theory claiming that, but there are other theories as well claiming moon to be some kind of mini planet earth catched on on its way throw your solarsystem.

    d) Yes, i think it does.

  • Anonymous
    1 decade ago

    The Moon's rotation period corresponds almost exactly

    to its period of revolution around Earth, so that the

    same half of the Moon is always facing us. Small

    changes in the attitude of the Moon, known as

    librations, allow us to see slightly more than half of

    the Moon in the long run.

    http://skytour.homestead.com/files/moonphase.html

    http://sems.und.edu/~sems/FrameA/MoonPhases/MoonPh...

    http://www.astro.virginia.edu/class/bastian/astr12...

    http://www.answers.com/topic/moon

    What are librations of moon?

    http://www-istp.gsfc.nasa.gov/stargaze/Smoon4.htm

    Some say that there is only one side of the Moon?

    http://www.school-for-champions.com/science/moon_m...

    http://www.fourmilab.ch/earthview/moon_ap_per.html

    Many people have heard that the same side of the moon

    always faces the earth, and because of this, many think

    that the moon does not rotate. It does rotate, exactly

    once for each orbit around the earth. Imagine looking

    down on the Earth and Moon from above the Earth's north

    pole. To illustrate this, place two coins on a

    table-top, one for the earth and one for the moon.

    Choose a reference point on the "moon" coin and place

    it closest to the earth keeping head. Now move the

    "moon" in a circle around the "earth" coin but keep

    head pointing to the earth. You will see that to

    accomplish this, you must rotate the coin exactly once

    for every trip around the earth.

    http://www.mmsd.org/planetarium/mooncal/moonfaq.ht...

    Why the lighted side of the Moon allways faces the Earth?

    http://home.hiwaay.net/~krcool/Astro/moon/moonphas...

    Is the outer crust is thinner on the near side of the

    Moon which faces earth?

    http://web.ics.purdue.edu/~nowack/geos105/lect8-di...

    What about the other side of the moon?

    It was the Russians who, in 1959, first took pictures

    of the unseen back of the moon. These historic pictures

    revealed that this hidden side differs significantly

    from the side which faces Earth: 98% of the back

    surface is highlands and there are only a handful of

    small mare. Additionally, the back side of the moon

    hosts the largest impact crater known to us in the

    Solar System. Boasting a diameter of 700 miles, Mare

    Orientalis is the remnant of an explosion whose force

    was strong enough to have sent a shock wave around the

    surface of the moon as far as the other side where it

    left cracks in the thin crust. The propagation of the

    shock wave can be seen most prominently in the

    concentric rings which surround the crater basin

    itself. The denotation "mare" for this remnant is

    misleading, as the melted rock in the center of this

    basin was not the result of a welling-up of liquid

    mantle from a deep crack in the crust but was rather

    contact melting of the surface rock from the tremendous

    heat of the explosion. An unanswered question remains

    about the moon abut why the crust on the far side seems

    to be tough enough to withstand an impact which should

    have destroyed the little moon, while the near side's

    crust is so thin as to have let mantle material escape.

    http://hea-www.harvard.edu/ECT/the_book/Chap6/Chap...

    Moon Illusion 1 - Some persons may judge that the

    right side is more distant than the left.

    http://www.lhup.edu/~dsimanek/3d/moonillu.htm

    Moon Illusion 2 - Moon near the horizon looks "larger"

    http://www.greenwych.ca/moonillu.htm

    http://facstaff.uww.edu/mccreadd/intro9.htm

    Is Moon constantly falling towards our Earth?

    http://www.elkforest.com/astronomy.html

    Then is the Moon moving away from the Earth?

    http://curious.astro.cornell.edu/question.php?numb...

    Which continents see the Moon as orange?

    http://www.strudel.org.uk/blog/astro/000305.shtml

    Reported flashes of light on the dark side of the Moon?

    http://www.daviddarling.info/encyclopedia/M/Moon.h...

    Are there any massive 'towers' on the moon?

    http://www.marsanomalyresearch.com/evidence-report...

    Which of the following could never happen?

    (a) An observer seeing a full moon in the middle of

    the day (local noon)

    (b) An observer seeing a new moon in the middle of the

    night (local midnight)

    (c) Both of the above observations are impossible for

    any observer to see.

    Does an astronaut on moon see the same side of

    earth all the time?

    For an astronaut on moon, how long the Earth takes

    to go through one complete cycle of phases?

    (astro.washington.edu/labs/

    clearinghouse/labs/

    word_documents/moonphases

    .html)

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  • Beckee
    Lv 7
    1 decade ago

    a)

    Because the moon takes the same amount of time to rotate on its axis as it does to orbit the earth once, the same side of the moon is always facing the earth. In other words, when it has gone one-quarter of its orbit around the earth, it has rotated 90 degrees. When it's gone halfway around the earth, it has rotated 180 degrees, and when it gets back to where it started from, it's back to where it started from.

  • Anonymous
    5 years ago

    No. The earth rotates that's the reason of why time exists. do no longer you spot there are cases whilst the moon isn't seen (daytime). If somebody became on the moon, they might see the earth rotate and can desire to basically see a similar spot on earth as quickly as each and every 24 (earth) hours.

  • The best answer is A. The moon spins in time with its revolution around the earth. This causes the same face of the moon to face the earth for almost ever. Eventually it won't be synchronous, but we won't see it within our lifetimes.

    That's my two cents for ya.

  • Anonymous
    1 decade ago

    Great herds of naked moon maidens were enslaved and forced to run around the moon's equator in the direction it was originally spinning, and so much angular momentum was transferred from the moon into the girls that the moon stopped spinning. Then along came some Vikings in spaceships, swooping down to snatch up the moon maidens... uh, in order to get a boost for their flight and save on rocket fuel. This is what prevented the angular momentum from returning to the moon.

  • 1 decade ago

    Hi,

    Our moon is fairly unusual in that it does not rotate, as we do, but completes its orbit around us always presenting the same face towards the earth.

    There are other examples of this feature in our solar system, but, as I say, it is rarer.

    No-one 'knows', though many offer theories, as to why this should be. They know why most DO rotate, but not why the few do not.

    I suspect you have already made your mind up to your own satisfaction, judging by the completeness of your question, but good question anyway.

    Cheers,

    BobSpain

  • 1 decade ago

    because the moon does not rotate over is own

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