Exam 9: Asteroids, Comets, and Dwarf Planets: Their Nature, Orbits, and Impacts

Pluto has 3 known moons.

How do asteroids differ from comets?

Pluto is most like a

Approximately how long ago was Pluto discovered?

A rocky leftover planetesimal orbiting the Sun is

The last major dinosaurs were wiped out as a consequence of a major impact with the Earth about 65 million years ago. All but one of the following statements would be regarded as evidence for this claim.

Which of the following is furthest from the Sun?

What do we mean by a primitive meteorite?

You've been dropped at the edge of a cliff, looking down for what seems to be miles! There's only one way to go from here: up! But it's going to be quite a climb, requiring all of your mountaineering skills. The atmosphere is very thin even at the mean surface level of this place. No matter, though, as you could not breathe this atmosphere anyway because it is mostly carbon dioxide and contains no oxygen. You climb and climb. This mountain must be three times the height of Mt. Everest and much broader at its base. There are clouds around you, and you can find water ice as well. When you try to melt some ice, however, it does not turn to liquid but sublimes to gas.

Suppose we discover a new comet on an orbit that brings it closer to the Sun than Mercury every 125 years. What can we conclude?

What is Charon?

The discovery of Eris ________.

If the hypothesis tracing the extinction of the dinosaurs to an impact is correct, the dinosaurs died off largely because ________.

The impact of a 100 meter asteroid could kill many people if it struck a major city. Suppose the probability of such an impact in any single year is 1 in 1,000, and suppose we know (somehow) that it has been 1200 years since the last impact. What would that tell us?

If the chance of the Earth being hit by a life-destroying asteroid over the course of one year is one in a million, what is the chance of being hit of the course of one hundred years?

In science fiction movies, spaceships are often shown dodging through large numbers of closely spaced, boulder-size objects. Which of the following real things in our solar system would look most like such science fiction dangers?

What is the typical size of a comet's nucleus?

Why do we sometimes observe asteroids at the distances of the gaps in the asteroid belt?

Which statement is not thought to be true of all comets in our solar system?

Suppose there were no solar wind. How would the appearance of a comet in our inner solar system be different?