• NAME
    Generally means satellite, (Luna was the Roman
    goddess of the moon).

    The moon is the Earth's only natural satellite. It's
    gravity is responsible for our ocean tides. It takes
    roughly 29 days to go through it's well known phases.
    The moon is also 'tidally locked' with earth, meaning we
    always see the same face of the moon. We never see the
    far side from Earth. The far side is not dark though.

    The surface appearance of the moon is largely craters
    and dark lunar maria. The mares ('seas') were thought
    to be water from their dark and flat appearance.
    It was realized that these areas were upwelling lava
    flooding portions of the moon, leaving these dark areas.
    Interestingly the lunar far side (photographed with
    spacecraft) has very little maria. There is no longer
    volcanic activity on the moon. This ended long ago when
    the moon, being a smaller body than the earth, cooled
    quickly after it's formation. Internal heat is generally
    necessary for volcanic activity.

    The craters were once thought to be formed from
    volcanic activity. It was later realized that craters are
    the result of meteorite impacts. Most of the craters
    were created long ago when the early solar system
    had much more leftover debris. The Earth presumably
    has had as many impacts, perhaps altering climate and
    causing some past extinction events, like that of the
    dinosaurs. Many craters have been identified on earth
    but they are usually covered with vegetation making
    them harder to find. The earth also is geologically
    active with earthquakes, volcanos and weather
    destroying all the older craters. The most famous
    crater is 'meteorite crater' in Arizona. It was the study
    of this crater that largely led to the belief that
    lunar craters were impact events and not volcanos.

    How did the moon get there? I think we still don't know.
    The best theory is that the early earth was hit by
    another large body, spewing debris around the earth.
    Gravity and collisions slowly collected all the material
    into what is now the moon.

    The moon is the only place where we have sent visitors.
    In july 1969 Neil Armstrong was the first to set foot
    on another world. 11 more astronauts would follow.
    The lunar rocks the astronauts returned were found to
    be very old. Little has changed on the moon in the last
    few billion years.

    When will we go back? Who knows. The Chinese have
    recently proposed going to the moon. The moon could be
    useful in many areas of interest. Astronomy has a lot of
    promise. The moon has no atmosphere, allowing for clear
    views of the universe. It could also be used by radio
    astronomers. The moon would block radio waves from
    Earth giving radio astronomers clear views of the skies.
    Small bases on the moon do not have to be expensive. The
    lunar soil can be used to make concrete. There may even
    be water at the lunar poles. The moon is rich in some
    minerals and could eventually be mined, saving us from
    making a bigger mess of this planet. We'll soon see if
    there are men of courage and vision out there who
    could make these dreams a reality.


    None, unless we decide to construct some.

    A surprising amount can be seen. Try sketching it.
    Do this at first quarter or less. The full moon is often
    too glaring to see detail well. I've found the full moon
    can be well seen low in the sky, before it becomes too

    A wealth of detail can be seen. Even binoculars can be
    used to see some of the craters. As with the naked eye
    it's best not to view it at full moon. I've found the crescent
    phase most pleasing. You really need a good lunar atlas
    to detail all that can be seen. Even the smallest telescope
    will show considerable detail.

Scenes from the Apollo program.

A view of the moon, showing the Maria and craters.

From apollo. The Earth rising above the lunar landscape.