December 12, 2011

• Objective:– Observe and examine

spectra from different sources

• Agenda:– Spectroscope Lab– Moon Notes– Moon Video

A look at our nearest neighbor in Space!

The Moon

What is the Moon?• A natural satellite

Location, location, location!

• About 384,000 km (240,000 miles) from Earth

• 3,468 km (2,155 miles) in diameter (about ¼ the size of Earth)

Moon Theories• The Fission Theory: The Moon was once

part of the Earth and somehow separated from the Earth early in the history of the Solar System. The present Pacific Ocean basin is the most popular site for the part of the Earth from which the Moon came.

• The Capture Theory: The Moon was formed somewhere else, and was later captured by the gravitational field of the Earth.

• The Condensation Theory: The Moon and the Earth condensed together from the original nebula that formed the Solar System.

• The Colliding Planetesimals Theory: The interaction of earth-orbiting and Sun-orbiting planetesimals (very large chunks of rocks like asteroids) early in the history of the Solar System led to their breakup. The Moon condensed from this debris.

• The Ejected Ring Theory: A planetesimal the size of Mars struck the earth, ejecting large volumes of matter. A disk of orbiting material was formed, and this matter eventually condensed to form the Moon in orbit around the Earth.

The Moon’s Surface

• No atmosphere• No liquid water• Extreme

temperatures– Daytime = 130C

(265°F)– Nighttime = -190C

(-310 F)• 1/6 Earth’s gravity

Lunar Features - Highlands

• Mountains up to 7500 m (25,000 ft) tall

• Rilles (trenchlike valleys)

Lunar Features - Craters• Most formed by meteorite impact on the Moon

Lunar Features - Maria• Originally thought to be

“seas” by early astronomers

• Darkest parts of lunar landscape

• Mostly basalt rock

Maria

Craters

Movements of the Moon• Revolution – Moon orbits

the Earth every 271/3 days• The moon rises in the east

and sets in the west• The moon rises and sets

50 minutes later each day• Rotation – Moon turns on

its axis every 27 days• Same side of Moon

always faces Earth

Far Side of the Moon• First seen by Luna 3

Russian space probe in 1959

• Surface features different from near side– More craters– Very few maria– Thicker crust