When we look up into the night sky, the
Moon is the biggest thing we can see.
In fact, the Moon is smaller than the
Earth. The Moon looks so big because
it is not as far away as the stars and
other planets.
There are nine planets that go around
or "orbit" the Sun.
Earth, the planet we live on, is one of
those planets. It is the third planet from
the Sun.
The Moon orbits the Earth and, at the
same time, it spins around too. It takes
about 28 days for the Moon to spin
around, and also for it to go around the
Earth.
Astronomers look at the Moon and
stars and planets. Today, they have big
telescopes that let them see things that
are a long way away. The first
astronomers did not have such good
telescopes for studying the Moon.
When you look at the Moon, you can
see dark and light patches on it. The
first astronomers mistook the dark
patches for seas. They named them
things like The Sea of Clouds and The
Sea of Tranquility. The Moon does not
have any seas. The dark patches are
big, flat bits of ground called plains.
It looks as if the Moon shines down on
the Earth but, in fact, the Moon does
not have any light of its own. It looks
like it shines because it reflects the light
from the Sun.
The Moon is always round. But
sometimes it looks as if it is a different
shape. This is because we can only see
the part of the Moon that is in the light
of the Sun.
At the time of a new moon, we cannot
see the Moon at all. This is because the
other side of the Moon, which we
cannot see, is lit up.
As the Moon and the Earth turn, We
can see part of the Moon that is lit up.
This is called a crescent moon.
Each night we can see more and more
of the Moon that is lit up, until we can
see all of it. Then, night by night, it
looks as if the Moon is getting smaller
and smaller again, until it disappears at
the next new moon.
We say the Moon "waxes" as it gets
bigger and "wanes" as it gets smaller.
Sometimes, as the Moon orbits the
Earth, and the Earth orbits the Sun,
they cross each other. The Moon, or the
shadow of the Moon, can block out the
Sun as they cross.
When this happens, it becomes dark.
This is called an eclipse.
From the Earth, we always see the
same side of the Moon. We never see
the other side as it is always turned
away from the Earth. This is because
it takes the same time for the Moon to
spin around as it takes for the Moon to
orbit the Earth
Despite being a long way away, the
Moon does affect things on the Earth.
As the Moon travels around, it attracts
the Earth and its seas.
When the Moon is close to one part of
the Earth, there is a high tide. As the
Moon travels away, the sea levels fall
and it is low tide.
We could not live on the Moon. It is
rocky, dry and barren. The Moon's
night is very, very cold and the Moon's
day is very, very hot.
Man has always looked at the Moon
and dreamed about visiting it.
Man first landed on the Moon in 1969.
Six rockets have landed on the Moon
and twelve men have walked on it. The
gravity on the Moon is less than on the
Earth. This is why, when you see
someone walking on the Moon, they
seem to jump and float along.
The first rockets to go to the Moon
were called Saturn rockets. Only a very
small part of a rocket, the bit at the
top, lands on the Moon. The rest of it is
filled with fuel. It has three parts, and
each part falls off as the fuel in it is
used up.
When you look at the Moon with a
telescope, you can see where rocks have
crashed into it. The marks never get
worn away as there is no weather on
the Moon.
This means that the footprints left by
the astronauts will still be there in
thousands of years' time!
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