7.4 Origin of the solar system  (Page 5/27)

What can we learn about the formation of our solar system by studying other stars? Explain.

Earlier in this chapter, we modeled the solar system with Earth at a distance of about one city block from the Sun. If you were to make a model of the distances in the solar system to match your height, with the Sun at the top of your head and Pluto at your feet, which planet would be near your waist? How far down would the zone of the terrestrial planets reach?

Seasons are a result of the inclination of a planet’s axial tilt being inclined from the normal of the planet’s orbital plane. For example, Earth has an axis tilt of 23.4° ( Appendix F ). Using information about just the inclination alone, which planets might you expect to have seasonal cycles similar to Earth, although different in duration because orbital periods around the Sun are different?

Again using Appendix F , which planet(s) might you expect not to have significant seasonal activity? Why?

Again using Appendix F , which planets might you expect to have extreme seasons? Why?

Using some of the astronomical resources in your college library or the Internet, find five names of features on each of three other worlds that are named after real people. In a sentence or two, describe each of these people and what contributions they made to the progress of science or human thought.

Explain why the planet Venus is differentiated, but asteroid Fraknoi, a very boring and small member of the asteroid belt, is not.

Would you expect as many impact craters per unit area on the surface of Venus as on the surface of Mars? Why or why not?

Interview a sample of 20 people who are not taking an astronomy class and ask them if they can name a living astronomer. What percentage of those interviewed were able to name one? Typically, the two living astronomers the public knows these days are Stephen Hawking and Neil deGrasse Tyson. Why are they better known than most astronomers? How would your result have differed if you had asked the same people to name a movie star or a professional basketball player?

Using Appendix G , complete the following table that describes the characteristics of the Galilean moons of Jupiter, starting from Jupiter and moving outward in distance.

This system has often been described as a mini solar system. Why might this be so? If Jupiter were to represent the Sun and the Galilean moons represented planets, which moons could be considered more terrestrial in nature and which ones more like gas/ice giants? Why? (Hint: Use the values in your table to help explain your categorization.)

Calculate the density of Jupiter. Show your work. Is it more or less dense than Earth? Why?

Calculate the density of Saturn. Show your work. How does it compare with the density of water? Explain how this can be.

What is the density of Jupiter’s moon Europa (see Appendix G for data on moons)? Show your work.

Look at Appendix F and Appendix G and indicate the moon with a diameter that is the largest fraction of the diameter of the planet or dwarf planet it orbits.

Barnard’s Star, the second closest star to us, is about 56 trillion (5.6 × 10 ¹² ) km away. Calculate how far it would be using the scale model of the solar system given in Overview of Our Planetary System .

A radioactive nucleus has a half-life of 5 × 10 ⁸ years. Assuming that a sample of rock (say, in an asteroid) solidified right after the solar system formed, approximately what fraction of the radioactive element should be left in the rock today?