http://www.psi.edu/node/5657

Lunar Geology

1. Internal Layers

2. Seismometer Data

3. Prospector Data

4. Possible Origins

5. Major Surface Features

6. Miscellaneous Facts!

http://www.psi.edu/node/5657

Internal Layers, Seismometer Data, and Prospector Data

Crust 65 km

Mantle 950 km

Core 200 km

Seismometers were deployed at Apollo 11, 12,

14, 15 and 16 landing sites. Transmissions were received until 1977.

Buzz Aldrin – Sea of Tranquility

The Lunar Prospector was launched January 1998.

The onboard magnetometer and Doppler Gravity Detector provided additional data of the Moon’s

interior and supported seismometer data.

Earth’s and Moon’s Internal Layers

Earth’s and Moon’s Internal Layers

Moon Layers

• Crust– Dry, dusty, rocky– Thicker on the far side than the near side– Rocks formed 4.3 billion years ago

• Rigid Lithospheric Mantle– Not hot enough to flow

• Nonrigid Asthenospheric Mantle– Only the deepest parts are hot enough to flow

• Core– Iron rich, but does not generate much of a

magnetic field

How Much Would I Weigh On The Moon???

• The moon’s gravitational pull is one sixth of the gravitational pull you experience on Earth.

• Calculate your weight on the moon.

• Calculate your mass on the moon.

Moon Formation Theories

• The moon formed elsewhere in the solar system, then was captured into Earth’s orbit.

• Capture into the moon's present orbit is very improbable.

• Something would have had to slow the moon down by just the right amount at just the right time.

Theory 1: Capture

• The moon formed in orbit about the Earth via accretion.

• If the moon formed in the vicinity of the Earth, it should have nearly the same composition -- specifically a large iron core.

Theory 2: Co-Formation

• A rapidly spinning Earth could have cast off the moon from its outer layers. • The Earth-Moon system does not contain evidence of this rapid spin.

• All of these hypotheses do not address the extra baking that lunar material has received.

Theory 3: Fission

• A Mars-sized object (name???) struck Earth, exploding the outer layers of both objects. The moon formed from this ejected material.

• Catastrophic collisions were common in the early stages of the solar system.

• Computer models show that a collision at a certain speed and angle will produce the right amount of debris in Earth’s orbit.

• Today, this scenario is widely accepted.

Theory 4: Catastrophic Collision

A crazy theory that actually works!

http://www.youtube.com/watch?v=c0FCE4H0Dro

Major Surface Features

Entire surface is covered with

craters

Dark circular regions are

called maria or lunar seas

Lighter surface areas are

called lunar highlands

Dark color was caused by meteor impacts that created lava flows and formed basalt

Water on the Moon

• Meteorites may have transferred water to the moon.

• Ice may be present in the permanently dark craters at either lunar pole.

• 650 square miles at each pole, totaling 6.6 billion tons.

Water on the Moon

• Why do we care about water on the moon?– Ice’s presence helps narrow models of

moon formation and early solar system activity.

– Shipping water to the moon for human use would be expensive (at least $2000/kg).

– Water could be converted into breathable oxygen and rocket fuel.

http://www.youtube.com/watch?v=YrLuOFoPlRc

Lifeforms on the Moon

• Hints of microbial life have been found, but no distinctive evidence has surfaced.

• The moon is too hostile to support life.– Very thin atmosphere of Ne, He, H, Ar, Na, K.– Temperatures fluctuate between -173°C during

the night and 125°C during the day.

• Fossil evidence may have been transferred to the moon from Earth by meteorite impacts.

http://www.youtube.com/watch?v=H2xaFLR0V4k

What Have We Found on the Moon?

• Lunar rocks and soil– More than 800 pounds have been collected

and returned to Earth.– Most are found in the Johnson Space

Center in Houston.– It is illegal for a private individual to own a

lunar rock!

Miscellaneous Facts

• Where did the moon get its name?– “Moon” came from the Old Norse mani, the

Greek mene, or the Latin mensis (month).

• How big is the moon?– 2,159 miles in diameter, 8.1x1019 tons

• How far away is the moon from Earth?– 238,857 miles on average.

• Why is the moon round?– Due to its rotation and gravity.

• How long is a day on the moon?– The moon’s day is the same as its year: 27.3

Earth days.

• What is the “dark side” of the moon? Have we ever gone there?– Due to tidal locking,

the same side of the moon always faces us.

– Both sides can be light OR dark, depending on where the moon is in its revolution around Earth.

• What is the “dark side” of the moon? Have we ever gone there?– So…“dark side” of

the moon is an inaccurate term. More descriptive terms are “far side” and “near side” of the moon.

– We have walked on the near side of the moon and have photographed the far side of the moon.

http://www.youtube.com/watch?v=OZIB_leg75Q