Exploring the Solar System

1. Why has knowledge of the Solar System increased greatly in recent years?

2. How and why do space scientists use gravity assists to propel spacecraft through the Solar System?

3. Which planets have been visited by spacecraft from Earth, and on which planets have spacecraft actually landed?

4. Why do you think Galileo and Cassini took such circuitous routes to Jupiter and Saturn while Pioneer and Voyager did not?

5. How do you think NASA's new policy of less complex, smaller, and cheaper spacecraft – with shorter times between design and launch – will affect the exploration of the outer planets? Will missions like Galileo and Cassini be possible in future?

6. Prior to radar, how were distances measured in the solar system?

7. How is radar ranging used to determine the Astronomical Unit (A.U.)?

8. What is the key ingredient in the modern condensation theory of the Solar System's origin that was missing or unkown in the nebular theory?

9. Give three examples of how condensation theory explains the observed features of the present-day Solar System.

10. Why are the Jovian planets so much more massive that the terrestrial planets?

11. How did the temperature structure of the solar nebula affect the planetary composition?