Earth Science Lesson 1
The Solar System

Pre-Test
Q&A	Investigating Astronomy

Instruction 1-3

The Solar Nebula/Earth's Formation from the Nebula | Cloud of Dust Theory | Formation and Origin of the Moon | Early Earth | The Sun | Effects of Asteroid Impacts in Shaping the Surface of Planets | Evidence for the Existence of Planets Orbiting Other Stars | Summary

Formation and Origin of the Moon
http://www.windows.ucar.edu/tour/link=/teacher_resources/impact_theory.html

The Moon is Earth’s nearest neighbor. We look up at the Moon at night. Romantics sing songs about it. The Moon revolves around the Earth once every month in what is called the Lunar Cycle (“luna” means “moon”). And both the Earth and the Moon revolve around the Sun.

But have you ever wondered where the Moon came from? Up until 1969, there were three major theories about the origin and formation of the Moon.

These theories were The Fission Theory, The Capture Theory and The Double Planet Theory.

The Fission Theory was proposed by G. H. Darwin, the son of naturalist Charles Darwin. This theory suggests that the Moon was spun out of Earth’s mantle during an early period in Earth’s development. (The Earth, as you remember, is made up of three layers: the core, the crust and the mantle. The mantle is the middle layer.)

The Capture Theory suggests that the Moon was formed somewhere else in the Solar System and then “captured” or pulled into orbit around the Earth.

The Double Planet Theory suggests that the Earth and the Moon simply grew together out of the ancient cloud from which our Solar System was born.

But in 1969, the Apollo Mission took men to the Moon. And that changed everything. Because the Apollo astronauts not only made scientific observations, they brought back rocks from the surface of the Moon. And these lunar rocks proved that none of the three previous theories was correct. Why?

Because although Moon rocks do contain elements found in Earth’s mantle, they also contain elements that had to have come from somewhere else. This discovery led to an entirely new theory about the origin and formation of the Moon.

Scientists now believe that the early Solar System was a very violent place. As planets were being formed, huge bodies of matter kept crashing into one another. About 4-1/2 billion years ago, an object about the size of Mars crashed into the developing Earth. This collision created debris both from the Earth and from whatever had crashed into it.

Eventually the debris from these two bodies combined and condensed. And that, according to the new theory, was what formed the Moon. Why do scientists think this happened 4-1/2 billion years ago? Because that’s  how old the oldest Moon rocks are. Can scientists prove this theory? They’re trying.

Experiments for Home and Classroom

The environment on the Moon is vastly different from the environment on Earth. This activity teaches students what is needed to sustain human life on the Moon as they build a model lunar settlement that must house humans for at least a year. Click http://cse.ssl.berkeley.edu/AtHomeAstronomy/activity_04.html

In this experiment, a baseball and a table lamp demonstrate the phrases of the Moon. Visit the Bill Nye the Science Guy site and click Hd for "home demos." Then go to (1) Planetary Science (2) Space Science and (3) Baseball Moon. Click: http://www.billnye.com/flash.html 

In this second Bill Nye experiment, students learn why the Moon appears to be different sizes at different times. Go to the Bill Nye site, click Hd for "home demos" and go to (1) Planetary Science (2) Space Science and (3) Once in a Mega Moon. Click: http://www.billnye.com/flash.html

As a follow-up to the previous experiment, students can learn to make their own astrolabe -- a device used for centuries to measure latitude, time and altitude, including  the height of objects in the sky -- like the Moon. Click: http://cse.ssl.berkeley.edu/AtHomeAstronomy/activity_07.html 

In another activity related to the size of objects in space, students learn to measure the Sun and the Moon. Click: http://cse.ssl.berkeley.edu/AtHomeAstronomy/activity_02.html 
 

Now let's do Practice Exercise 1-3 (top)

Next Page:  Instruction, page 4 (top)