1. Impacts on Earth

2. Read The Crater That Ended the Reign of the Dinosaurs. Answer the questions in your journal. How big would this crater be in Phoenix? Look on page 27 of your book at Barringer Crater in Arizona. Created about 50,000 years ago. A meteoroid about the size of a house hit the Earth. The crater is about 1 km across. (A little over ½ mile.)

3. The Moon and Earth have been around for about the same time. Over 4 billion years. There is evidence of massive bombardment on the Moon, but not Earth. Why? Did Earth not get hit? Was it protected? Did Earth get hit, but we just can’t see it? Did Earth get hit and now the craters are gone? Are there some, but we just can’t see them? Discuss…..

4. http://www.fossweb.com/delegate/ssi-foss- ucm/Contribution%20Folders/FOSS/multimedia_ms_1E/Planet aryScience/binders/ea_geology_1_1_e.htm http://www.fossweb.com/delegate/ssi-foss- ucm/Contribution%20Folders/FOSS/multimedia_ms_1E/Planet aryScience/binders/ea_geology_1_1_e.htm Chicxulub Crater. This crater is believed to be the impact that ended the reign of the dinosaurs. So, where have the Earth craters gone? Erased by wind, rain, tides, etc. Data: Less than 150 identified. Most are small, young, heavily eroded. Only a handful are over 500 million years old. Only ½ dozen are over 100 km in diameter. Most are less than 25 km in diameter.

5. Look at your book, pages 30-31. Can you see evidence of erosion? Look at pg. 31. The craters on page 31 were partially eroded at a time when Mars had water flowing on it. When the process stopped billions of years ago, what was left was preserved. This is further proof that impact craters have eroded on Earth.