1. Why is the phrase “dirty snowball” an appropriate characterization of a comet’s nucleus? 2. What and where is the Kuiper belt, and how is it related to debris left over from the formation of the...

1. Why is the phrase “dirty snowball” an appropriate characterization of a comet’s nucleus?

2. What and where is the Kuiper belt, and how is it related to debris left over from the formation of the solar system?

3. Why do scientists think the Tunguska event was caused by a large meteoroid and not a comet?