Figuring for Yourself
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.
Barnard’s Star, the second closest star to us, is about 56 trillion (5.6 × 1012) 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 × 108 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?