| A | B |
|---|
| Why are the inner planets called terrestrial planets? | they resemble Earth |
| What is the most useful unit for measuring distances within the solar system? | the astronomical unit |
| Why do active planets generally have fewer impacts than bodies like the moon? | geological activity removes their effects |
| What is one way that gas giants differ froom terrestrial planets? | their atmospheres are massive |
| What is the current theory about the origin of the moon? | the moon resulted when a large body struck Earth |
| What is the evidence that Mars once had liquid water? | features that resemble dry river beds |
| This planet is known for its spectacular ring system | Saturn |
| This is the smallest planet in the solar system | Pluto |
| This planets year is only 88 Earth days long | Mercury |
| This planet had a storn system called the Great Dark Spot | Neptune |
| This is the only planet known to contain life as we know it | Earth |
| This planet spins with a retrograde rotation | Venus |
| This moon seems to have broken apart and been pieced back together by gravity | Miranda |
| This moon is larger than the planet Mercury | Ganymede |
| This moon reveolves around its planet in a retrograde orbit | Triton |
| This moon is the largest sattelite relative to the size of its planet | Charon |
| This moon is oddly shaped and may be a captured asteroid | Phobos |
| This moon originated when a planet-sized body collided with Earth | Luna |
| Why do we always see the same side of the moon from Earth? | its period of rotation equals its period of revolution |
| Why is it important to study smaller bodies such as comets or asteroids? | They help us learn the history of our solar system |
| Why don't solar and lunar eclipses occur every month? | the moon's orbit is tilted |
