Just about everyone wanted to know about the circles on the Moon. In the 1960’s two distinguished geologists thought about the craters on the surface of the moon and came up with two different explanations for their origin. They studied photographs of the Moon’s surface, similar structures on Earth, and, later, samples of Moon rocks returned by the Apollo 11 mission. The evidence convinced Dr. Jack Green that most of the craters were volcanic in origin; Dr. Eugene Shoemaker was convinced that the craters were created when pieces of flying space debris, called meteoroids, slammed into the Moon’s surface. We will now hear a presentation of the evidence by the two scientists. After the positions have been stated, we will think about how we might obtain additional information to support one position or the other.

Use back of p. 11 Label GREEN/SHOEMAKER DEBATE Make a T-Chart and take notes on both sides. After the debate you will have to write a comparison essay – Which scientist do you agree with and WHY??

Dr. GreenDr. Shoemaker 1. Volcanic activityHigh speed impact

Green and Shoemaker needed more information to settle the controversy. Can you think of ways to get more evidence to decide whether volcanoes or impacts caused these craters?

Lunar scientists have determined that it is possible to explain the presence of craters on the moon as the result of impacts by fast-moving objects. Experiments similar to the ones you completed showed that large meteoroids can produce large craters. One thing we are not able to reproduce in the classroom is the speed at which objects fly through space. Meteoroids travel so fast that, when they hit the moon, the energy released actually vaporize the meteoroid and part of the Moon’s rocky surface, causing an explosion. This explosive release of energy does most of the work creating the crater. View multimedia

Here is a basin with flour. The flour will represent The Lunar Regolith or moon soil and there will be a thin layer of cocoa powder over the “soil”. You will observe what happens when there is an impact (the crash between a meteoroid and another object).

Drop Height (cm) Crater Diameter cm Ray 1 cm Ray 2 cm Ray 3 cm Average Ray cm

How did speed (the higher you dropped the marble the faster it went) affect the craters that were made? At a higher speed, the craters are bigger, the marble went deeper and there were more rays that were longer.

Lunar scientists have determined that it is possible to explain the presence of craters on the moon as the result of impacts by fast-moving objects. Experiments similar to the ones you completed showed that large meteoroids can produce large craters. One thing we are not able to reproduce in the classroom is the speed at which objects fly through space. Meteoroids travel so fast that, when they hit the moon, the energy released actually vaporize the meteoroid and part of the Moon’s rocky surface, causing an explosion. This explosive release of energy does most of the work creating the crater. View multimedia

Look at p Find examples of: A large crater A small crater A long ray A central peak A different kind of crater (ghost or flooded)

Ejecta – material thrown out during crater impact Simple crater – a small crater shaped like a cup Complex crater – a larger crater with a central peak and rays Terraced crater – basin craters with step like ridges and long rays Flooded crater – large craters that are filled in with lava but rays and rims are still visible.

Ghost crater – the faintest of flooded craters Basins – gigantic craters – These were then flooded with lava and became the mare. Central Peaks – parts of a crater that are mountains in the middle.

Face of the Moon p. 26 Text AFJ BG DH Y Z X X came 1 st because it is the biggest. It is also the oldest. Then came Y and then Z. Z is the smallest and the youngest crater. The sun is on the west. Therefore it is afternoon.

p Read p. 63 to 64 and answer the Think Questions on the back of p. 14 in Notebook. Read p.65 to 66 and answer the Think Questions on the back of p.14 in Notebook.

Earth Craters The Moon and Earth have been around about the same length of time – over 4 billion years. There is evidence of massive bombardment and cratering on the Moon, but very little evidence of impacts on Earth. Why don’t we see thousands of craters on Earth? The atmosphere protects us from flying space debris!

Do you think it is possible we just don’t see these craters? The craters have been erased due to wind, rain, tides and other forces on Earth. Erosion – The gradual wearing away of land due to water, wind and glacier activity. Use the computer to look up craters on Earth. Write 1-2 paragraphs explaining where the crater is, the age of the crater and the size of the crater. Include other facts as well. This is extra credit – due Monday.

Asteroids: Deadly Impact 1. Gene Shoemaker is a geologist. 2. An asteroid is a rock in space. 3. Shoemaker Levy 9 is a comet and it hit Jupiter. 4. We will get no warning. 5. They believed craters were caused by volcanoes. 6. It took 2 decades.

7. He found underground explosions could cause craters. 8. He explained it by a bullet hitting the sand. 9. He found that the town was built inside a crater and the church was built from a coesite. 10. No, because of medical issues. 11. It is located between Mars and Jupiter. 12. It would be the size of Texas.

Gene Shoemaker: The First Man on the Moon Explain how Eugene Shoemaker was the real first man on the Moon.

The Crater That Ended the Reign of the Dinosaurs – p Answer the 1 st 2 Think Questions on the back of p.15 in Notebook.

The Origin of the Moon We have been observing the Moon to see what it’s doing day after day, and we’ve been taking close looks at some telescope photos of the surface of the Moon. We now have answers to some of the questions we asked a couple of weeks ago. Where did the Moon come from? I think that …

Origin of the Moon Read comic View simulation of Moon Origin Create a poster illustrating the theory you agree with and explain why you agree with this theory.

Theories Capture Theory – Moon got to close to Earth and got caught by the gravity. Sister Theory – The Moon and the Earth formed at the same time. Daughter Theory – When the Earth was forming, it was spinning so fast that a piece broke off and formed into the Moon. Big Impact Theory – A large sized object slams into the earth causing debris to fly out to space. This debris becomes the Moon.

How to Get and Hold onto a Moon p Which theory is correct on how the Moon was created? The Big Impact Theory!! A large object strikes the Earth Material from Earth’s outer layer breaks off The material is thrown into space The material in orbit forms into the Moon