Friday October 1, 2010 (Earth’s Moon and Lunar History)

The Launch Pad Friday, 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.

 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 IssuedDate 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 Moon The 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).

 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

 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 Tectonics are no longer active.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.

 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

Mare Highlands

Figure 22.6

Download a picture of the Moon and label the areas indicated in this example. Use Open Office Impress. A B C D F G H I J K L