friday october 1, 2010

FridayOctober 1, 2010(Earth’s Moon and

Lunar History)

The Launch PadFriday, 10/1/10

Name and describe the two major influences of our Sun.The gravitational influence is the hold the Sun has on material objects and is what

determines the extent of our solar system. The radiational influence of the Sun is

known as the heliosphere, which is a bubble in space produced by the solar wind.

Announcements Today is the last

opportunity to do anything about your grade for this six-weeks.

I will be leaving promptly at 5:00 PM this afternoon.

Assignment Currently Open Pages Date of Notes

on Website Date Issued Date Due

Earth’s Moon Lunar History

The current hypothesis suggests that a giant asteroid collided with the Earth

to produce the Moon. The older areas have a higher density.

The younger areas are still smooth.

The Formation of the MoonThe current preferred hypothesis regarding the

Moon’s formation is the ‘collision’ theory. It is, so far, the best at explaining how compositions of rock from the Earth and rock from the Moon differ.According to the collision theory, at the dawn of the Solar System a heavenly body the size of Mars hit

the young Earth.As a result, material from the rocky mantle of the heavenly body and of the Earth was hurled into

space.This collected in the shape of a ring on a path closely orbiting the Earth where it then gradually ‘clumped

together’ to form the Moon.

The Formation of the Moon

Earth’s Moon Lunar History

The Moon evolved in three phases:1. original crust (highlands)

As the Moon formed, its outer shell melted, cooled, solidified, and became the highlands - about 4.5 billion years ago.

2. formation of maria basins Maria basins are younger than the highlands – they formed between 3.2 and

3.8 billion years ago.3. formation of rayed craters

The material ejected from craters is still visible as rays - e.g., Copernicus and Tycho (rayed craters).

Earth’s Moon Our Moon’s General Characteristics: • The Moon has a diameter of 3,475 km (2,160 miles) - unusually large compared to its parent planet, the Earth.

• Density of the Moon ▪ 3.3 times that of water▪ comparable to Earth’s crustal rocks▪ perhaps the Moon has a small iron core

Earth’s Moon Our Moon’s General Characteristics: • The Moon’s gravitational attraction is one-sixth of Earth’s.

• The Moon has no atmosphere.• Tectonics are no longer active.• Our Moon’s surface is bombarded by micrometeorites from space, which gradually makes the landscape smooth.

Earth’s Moon The Lunar Surface – Two Types of Terrain

▪ Maria (singular, mare), Latin for “sea”• dark regions• fairly smooth lowlands• Originated from asteroid impacts and lava flooding the surface .

▪ Highlands • Bright, densely cratered regions• Make up most of the Moon• Make up all of the far side of the Moon• Older than maria

Earth’s MoonMare

Highlands

Major Topographic Features on the Lunar Surface

Figure 22.6

Assignment

Download a picture of the

Moon and label the

areas indicated in

this example.

Use Open Office

Impress.

A

B

C

DF

G

H

IJ

K

L