Astro 120: Fall 2003
Exam 2 Essay Question
PART II: ESSAY (20 points):
Answer the question on this sheet front and (if needed) back only
Section Number: __________________
Throughout this part of the course, we have looked at the planets of our
Solar System, and the small bodies that attend them (satellites and rings).
Though they display a huge range of properties, there are some important
similarities between features found on their surfaces, and in their
atmospheres. With this in mind, answer each of these two questions, in a
brief but well reasoned paragraph using proper English grammar.
You may use diagrams to illustrate your point(s), in addition to the words.
(10 pts) Impacts of bodies larger than 30 meters in diameter produce
craters on the surfaces that they hit. We see a large number of craters on
the surfaces of most satellites of the planets, and on most of the
terrestrial planets. However, some solid bodies show few if any craters.
One of them is the Earth. Explain why the Earth, and one other body in the
solar system that has a solid surface, show few if any impact craters. In
your answer be sure to address the following points with specifics.
- Is the lack of craters connected to a lack of objects that can crash
into the bodies?
- If so, why are there so few objects? If not, where are the craters?
(10 pts) In all planets that have atmospheres, we see clouds. For
example, the clouds of Venus appear greenish-white; Earth clouds are white,
Jupiter has white, brown, and even red clouds, Neptune has a vivid blue-green
color. Pick any two planets with different colored clouds (you don't need
to restrict yourself to the ones mentioned above) and explain why the clouds
look different on each planet. As a hint, for each planet be sure to
mention the main constituent of its atmosphere and that of the clouds we see.