Our MoonOur MoonA Closer look at…

Created by: Janet D’Santos

The moon is a “natural The moon is a “natural satellite”. A satellite”. A satellitesatellite is is

anything the anything the orbitsorbits the earth. the earth.Artificial satellites have four main Artificial satellites have four main uses:uses:

– CommunicationsCommunications– Monitoring the weatherMonitoring the weather– Observing the EarthObserving the Earth– Exploring the solar systemExploring the solar system

The moon is a cold, dry orb whose surface is The moon is a cold, dry orb whose surface is studded with craters and strewn with rocks and studded with craters and strewn with rocks and

dust. The moon has no atmosphere. Recent lunar dust. The moon has no atmosphere. Recent lunar missions indicate that there might be some missions indicate that there might be some

frozen ice at the poles.frozen ice at the poles.

The Moon’s movementThe Moon’s movement

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

How far away is the Moon?How far away is the Moon? The moon is about The moon is about

238,900 miles 238,900 miles (384,000 km) from (384,000 km) from Earth on average. Earth on average.

At its closest point At its closest point the moon is 221,460 the moon is 221,460 miles (356,410 km) miles (356,410 km) from the Earth. from the Earth.

At its farthest At its farthest approach the moon approach the moon is 252,700 miles is 252,700 miles (406,700 km) from (406,700 km) from the Earth.the Earth.

Size of the MoonSize of the Moon The moon's The moon's diameterdiameter is is

2,140 miles (3,476 2,140 miles (3,476 km), the Earth is 7,900 km), the Earth is 7,900 miles (12,742 km) in miles (12,742 km) in diameter. That's how diameter. That's how far you would have to far you would have to tunnel to dig to the tunnel to dig to the other side of the Earth! other side of the Earth!

The The circumferencecircumference of of the moon is the moon is 6,790 miles 6,790 miles (10,864 km). The (10,864 km). The circumference of the circumference of the earth at the equator is earth at the equator is 24,901.55 miles 24,901.55 miles (40,075 km). (40,075 km).

How much does the Moon How much does the Moon weigh?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.

The Atmosphere on the Moon

TEMPERATUREThe temperature on the Moon ranges from daytime highs of about 130°C = 265°F 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.

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.

Man on the MoonMan 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."

How did the Moon form?How did the Moon form?

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

VocabularyVocabularyAxis: Axis: An axis is an imaginary straight line around which an An axis is an imaginary straight line around which an

object, like a planet, turns.object, like a planet, turns. Circumference: Circumference: the distance around the equator the distance around the equator

Diameter: Diameter: the width from one side to the other the width from one side to the other through the centerthrough the center

Orbit:Orbit: path that an object takes as it moves around path that an object takes as it moves around another bodyanother body

Revolve: Revolve: wwhen an object moves in orbit around another hen an object moves in orbit around another objectobject

Rotate: Rotate: to turns or spin around a central point or to turns or spin around a central point or axis.axis. One day is defined as the time it takes the planet One day is defined as the time it takes the planet to rotate around its axis. to rotate around its axis.

Satellite:Satellite: objects that orbit a planet or a moon.objects that orbit a planet or a moon.