The origin of the Moon. - What do observations of the Moon suggest about its origin?

discussion questions - f. Which is hotter, Mercury or Venus? Why? h. Explain why there are two general families of planets, rocky terrestrial and gaseous jovian. j. What knowledge do comets and asteroids provide to studies of the origin of the solar system?

Comparing the ages of the Earth and Moon. - If the ages of the Earth and Moon are nearly identical, as believed, why are most rocks found on the Moon so much older than earth rocks?

The discovery of Uranus and Neptune. - The first planets discovered since ancient times were Uranus and Neptune. Compare how they were discovered.

The differences between Earth's and Venus' atmospheres. - Venus and Earth are about the same size and mass, yet carbon dioxide is a major constituent of the atmosphere of Venus, while oxygen is much more abundant in the Earth's atmosphere. Explain why the atmospheres are so different.