ASTR220 Spring 2003

QUIZ #1 (worth total of 10 points)

 

 

Name (1 point):                                                

 

 

This quiz has three kinds of questions: true/false questions (worth ˝ point each), multiple choice questions (worth 1 point each) and short answer questions (worth 2 points each).  For the true/false and multiple choice questions, please circle the correct answer.  You will have about 20 minutes to complete this quiz.  Please do not use any notes or calculators.

 

 

  1. All comets and asteroids orbit in the same plane as the planets.
    1. True
    2. False

 

 

 

  1. All craters on the Moon are circular because all of the objects that struck the Moon were spherical.
    1. True
    2. False

 

 

 

  1. Impact craters are common in the Solar system because:
    1. A storm of asteroids passed through the Solar system about 1 billion years ago
    2. Collisions were very common as planetesimals and planets formed
    3. A giant collision formed the Moon and left many small objects behind
    4. The Sun flung out chunks of matter as it formed, and these hit the planets

 

 

 

  1. Which of these facts supports the idea that the Moon was formed from the Earth by a giant impact about 4.5 billion years ago?
    1. The Moon is round
    2. The Moon is heavily cratered
    3. The Moon has a composition very similar to the Earth’s mantle
    4. The Moon has no atmosphere.

 

 

 

 

  1. On the Earth, the craters with a diameter small than 2-4km are “simple” craters, whereas those with greater diameter are “complex” craters.  On the Moon, the dividing line between simple and complex craters is much larger, approximately 20km.   What is the main cause for this difference?
    1. The Moon has a weaker gravitational pull at its surface than does the Earth, so the sides of the crater do not collapse so easily.
    2. Lunar rock is harder than typical Earth rock, so the sides do not collapse so easily and you can get bigger simple craters.
    3. Erosion causes simple craters, and is much more effective on Earth.
    4. We do not know why this difference exists.

 

 

 

  1. We believe that the Tunguska events was caused by:
    1. The explosion of a mini black hole
    2. A UFO crash landing
    3. The mid-air explosion of a fast moving asteroid fragment
    4. The mid-air explosion of a lump of anti-matter.

 

 

 

 

  1. What is Iridium?  Briefly describe why is it important in the study of impacts.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

  1. Draw two diagrams showing the structure of simple and complex craters.  Be sure to label the important structures associated with the crater.