Download Moon Did you ever look at the Moon and think you could see a face

Moon
Did you ever look at the Moon and think you could see a
face? Sometimes dark spots on the Moon look like eyes, a
nose, and a mouth. People used to talk about “the man in
the Moon.” They would joke about the Moon being made
of cheese with holes in it.
The Moon is the second brightest thing in our sky, after
the Sun. The Moon doesn’t make its own light. Light rays
from the Sun bounce off it and make it shine. The Moon is
closer to Earth than any other body in our solar system.
WHAT’S ON THE MOON?
In the 1600s, the famous Italian scientist Galileo was the first
person to look at the Moon through a telescope. He saw dark
spots that he thought were oceans. He called them maria, the
Latin word for “seas.” Galileo thought the light areas were large
landmasses called continents.
Today, we know a lot more about the Moon. We know that
nothing lives on the Moon, and there are no oceans. The maria
are dry, flat plains covered with rocks. The Moon is the only
place in space that human beings have visited.
TOUCHING THE MOON
The first astronauts landed on the Moon in 1969. They traveled
in a United States spacecraft named Apollo 11. The astronauts
set up experiments on the Moon and brought some moon rocks
back to Earth. Later, five more Apollo missions explored
different parts of the Moon. The astronauts on these missions
brought back more rocks and soil.
Scientists learned many things about the Moon from the Apollo
space missions. They also learned from other spacecraft that
orbited (went around) the Moon. Some of these spacecraft sent
robot landers down to the surface of the Moon.
SPACE ROCKS AND CRATERS
The dry, gray Moon might seem like a boring place now. But you
should have seen it several billion years ago.
Many times over the past two or three billion years, chunks of
rock and ice have come whizzing toward the Moon. The space
rocks and ice are asteroids and comets. They slam into the
Moon’s surface. The biggest ones came just after Earth and the
other planets were formed. When they hit the Moon, these large
objects threw up tons of rock and dust. There are billions of big
and small pits on the Moon made by the space rocks. These pits
are called craters.
ANCIENT VOLCANOES
If you went to the Moon, you’d see the dark-colored maria.
Scientists think the dark gray rock is lava (melted rock). They
believe that billions of years ago, red-hot rock gushed up from
volcanoes on the Moon. The lava flowed over the Moon’s surface.
It filled in low places, including some of the big craters. Then the
lava cooled to make the Moon’s gray rocks.
The lava also left round hills on the Moon called domes and
carved grooves called rilles.
ROUGH HIGHLANDS
There are rough and mountainous places all over the Moon.
Scientists call these places highlands.
There are highlands on the far side of the Moon but almost no
maria. Only one side of the Moon faces Earth, so you can never
see the far side of the Moon. Scientists learned what the far side
looks like from pictures taken by orbiting spacecraft.
HOT DAYS AND COLD NIGHTS
The astronauts who walked on the Moon had to wear big space
suits. The space suits provided air for the astronauts to breathe,
because there is no air on the Moon. The suits also kept the
astronauts cool during hot Moon days and warm during cold
Moon nights.
With no atmosphere to protect it, Moon temperatures can be
very high and very low. It can be 261° Fahrenheit (127° Celsius)
at noon during a Moon day—hotter than boiling water! It can be
as cold as -279° Fahrenheit (-173° Celsius) on a Moon night.
Days and nights on the Moon each last about two weeks.
Days and nights are long because the Moon turns very slowly. It
takes the Moon about 27 days to make one turn. Earth turns
once every 24 hours.
ICE ON THE MOON?
There is no water on the Moon, but scientists think that there
may be ice. Two spacecraft in the 1990s saw signs of the ice. If
there is ice on the Moon, it could help future explorers stay there
longer.
The signs of ice were found in deep craters at the north and
south poles of the Moon. Because these craters are always in
shadow, it stays very cold there—about -364° Fahrenheit (-220°
Celsius).
THE MOON FROM EARTH
The Moon always seems to change shape. Sometimes it looks
like a round ball in the sky. Sometimes it is a thin sliver. But the
Moon does not really change shape. What happens to it?
The Moon reflects light from the Sun. How you see the reflected
sunlight depends on where the Moon is. The Moon orbits (goes
around) Earth. Sometimes it is between the Sun and Earth, and
you can’t see any reflected sunlight. This is called the new moon.
Sometimes Earth is between the Moon and the Sun. You can see
all of the reflected sunlight. The Moon looks round. This is called
a full moon.
The rest of the time, you see only part of the reflected sunlight
from the Moon. The reflected sunlight looks like slivers of Moon.
It takes about 27 days to go from a new moon to a full moon and
back to a new moon again.
WHERE THE MOON CAME FROM
No one knows for sure how the Moon was formed. By testing
moon rocks, scientists have learned that the Moon is about 4.6
billion years old. This is the same age as the solar system.
Scientists think that at that time something as big as a planet
crashed into Earth. The collision blasted huge pieces of Earth
into space. Some of the pieces came together to make the Moon.
Scientists continue to study moon rocks for clues. There is still
much to learn about the Moon.
Microsoft ® Encarta ® 2007. © 1993-2006 Microsoft Corporation. All rights reserved.