The Moon

Satellite – Any body orbiting a central mass

No Atmosphere

No temperature regulation

Daytime temperature = 400 K (266 F)

Nighttime temperature = 100 K (-280 F)

Moon Facts:

• Moons Period- 29.5 days

• Moons Day- 29.5 days

• Distance- 250,000 miles

• Gravity- 1/6th that of the earth’s. 120 pound weight on the earth would weigh about 20 pounds on the Moon.

Atmosphere of the MoonThe moon has no atmosphere

Not really. About half of the present atmosphere of the Moon is from the exhaust of the Apollo Moon Missions!

Therefore, there is no weather on the moon.

No atmosphere means that wings (airplanes, helicopters, etc.) and parachutes won’t work.

It also means that there is essentially no protection from x-rays and micrometeorites on the Moon’s surface as there is on the earth.

Surface Features

Craters:

Mare - Dark, smooth lava filled regions

Highlands - lighter colored, rough terrain

Mountains - actually crater rims or sections of crater walls

Volcanic features

Mare tend to have circular edges

large impact basins that filled with lava

Areas without mare

Heavily cratered highlands

Impact made basin (bowl shape)

Lava filled basin creating mare

Later impacts occurred

Mare are younger (newer) than highlands

Rille

Faults

Structure of the MoonComposition of the Moon similar to the Earth’s Mantle

Very little metal (iron, nickel), mainly rock

Iron-rich core

Mantle

Crust

Lunar Crust

Near side Far side

Thinner crust on Near Side allows formation of Mare

Gravity of the Moon

The earth’s gravity pulls the moon and keeps it in orbit. (Without its motion, the moon would fall down to the earth. Without the earth’s gravity, the Moon’s motion would cause it to leave the earth.)

Does the Moon’s gravity pull on the earth? Are there any effects that we can see if the Moon does in fact pull on the earth?

Gravity of the Moon – Tides

What are tides, and what causes tides?

Are some tides bigger than others?

Is it in any way related to either the sun or the Moon?

We will try to answer the first question AFTER we answer the other three.

Tides:• Caused by the gravitational interaction

between the Earth and the Moon. The gravitational attraction of the moon causes the oceans to bulge out in the direction and opposite direction of the moon.

Spring Tides:• Spring tides- Strong Tides occur when the

Earth moon and sun align (has nothing to do with the season Spring)

Neap Tides:• Neap tides- Weak tides that occur when the

gravitational forces of the Moon and the Sun are perpendicular to one another

Tidal EffectsThe Earth’s pull slowed the rotation of the Moon (Tidally

locked)

The Moon’s pull is slowing the rotation of the Earth

(by about 0.7 seconds/year)

The Earth’s pull in also slowing down the Moon’s orbital

velocity - the Moon is getting further from the Earth by 3.8

cm/year

Far in the future, the Moon will be very far from us, one side

of the Moon will face one side of the Earth

Apollo Mission

6 lunar landings

12 people walked on the Moon (and played golf)

850 pounds of rocks

All near side landings

Lunar Rover

Lunar Rocks

Basalts - found in the mare, volcanic

Anorthosites - highlands, aluminum, calcium, silicates

Breccia - cemented rocks

Origin of the Moon

History of the Moon:

- Impact Theory- 4.5 billion years ago A very large asteroid hit earth with enough force to break a chunk of earth off which was caught in the earths orbit and became the moon.

- Moon has a similar mantle composition as earth