Our Moon

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Our Moon
A Closer look at
Created by Mrs. Bodine-Donahue
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The moon is a natural satellite. A satellite
is anything the orbits the earth.

• Artificial satellites have four main uses
• Communications
• Monitoring the weather
• Observing the Earth
• Exploring the solar system

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The moon is a cold, dry orb whose surface is
studded with craters and strewn with rocks and
dust. The moon has no atmosphere. Recent lunar
missions indicate that there might be some frozen
ice at the poles.
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The Moons movement

• The moon revolves around the Earth in about one
  month (27 days 8 hours). It rotates around its
  own axis in the same amount of time. The same
  side of the moon always faces the Earth it is in
  a synchronous rotation with the Earth.

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How far away is the Moon?

• The moon is about 238,900 miles (384,000 km) from
  Earth on average.
• At its closest point the moon is 221,460 miles
  (356,410 km) from the Earth.
• At its farthest approach the moon is 252,700
  miles (406,700 km) from the Earth.

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Size of the Moon

• The moon's diameter is 2,140 miles (3,476 km),
  the Earth is 7,900 miles (12,742 km) in diameter.
  That's how far you would have to tunnel to dig to
  the other side of the Earth!
• The circumference of the moon is 6,790 miles
  (10,864 km). The circumference of the earth at
  the equator is 24,901.55 miles (40,075 km).

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How much does the Moon weigh?
The moon's mass is about 1/81 of the Earth's
mass. The moon's gravitational force is only
17 of the Earth's gravity. For example, a 100
pound person would weigh only 17 pounds on the
Moon.
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The Atmosphere on the Moon

• TEMPERATUREThe temperature on the Moon ranges
  from daytime highs of about 130C 265F to
  nighttime lows close to -310 F.ATMOSPHEREThe
  moon has no atmosphere. On the moon, the sky is
  always appears dark, even on the bright side
  (because there is no atmosphere). Also, since
  sound waves travel through air, the moon is
  silent there can be no sound transmission on the
  moon.

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Craters
The surface of the moon is scarred by millions of
(mostly circular) impact craters, caused by
asteroids, comets, and meteorites. There is no
atmosphere on the moon to help protect it from
bombardment from potential impactors (most
objects from space burn up in our atmosphere).
Also, there is no erosion (wind or precipitation)
and little geologic activity to wear away these
craters, so they remain unchanged until another
new impact changes it.
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Man on the Moon
There have been many missions to the moon,
including orbiters missions and moon landings. On
July 20, 1969 Neil Armstrong was the first person
to set foot on the moon. His first words upon
stepping down the Lunar Module's ladder onto the
lunar surface were, "That's one small step for
man, one giant leap for mankind." Aldrin
described the lunar scenery as "magnificent
desolation."
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How did the Moon form?

• Most scientists believe that the moon was formed
  from the ejected material after the Earth
  collided with a Mars-sized object. This ejected
  material gathered into the moon that went into
  orbit around the Earth. This catastrophic
  collision occurred about 60 million years after
  Earth itself formed (about 4.3 billion years
  ago). This is determined by the dating of moon
  rocks.

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Vocabulary

• Axis An axis is an imaginary straight line
  around which an object, like a planet, turns.
• Circumference the distance around the equator
• Diameter the width from one side to the other
  through the center
• Orbit path that an object takes as it moves
  around another body
• Revolve when an object moves in orbit around
  another object
• Rotate to turns or spin around a central point
  or axis. One day is defined as the time it takes
  the planet to rotate around its axis.
• Satellite objects that orbit a planet or a moon.