15. Today, we believe that only a small number of elements were actually formed during the Big Bang. Which of the following was NOT one of these:

35. Astronomers estimate that there may be a trillion (a thousand billion) comet nuclei orbiting beyond Pluto. Why then do we not see more comets in our skies?

9. Which color star is likely to be the hottest?

3. When astronomers discuss a nebula, what are they talking about?

10. Which law do astronomers use to determine the masses of the stars in a spectroscopic binary system?

5. Astronomers today know a lot about the size and shape of the Milky Way Galaxy. Which of the following common objects most resembles the shape of our Galaxy?

11. A star whose temperature is increasing but whose luminosity is roughly constant moves in what direction on the H-R diagram?

3. When a single star with a mass equal to the Sun dies, it will become a

14. What evidence can you give that shows the surface of Jupiter?s moon Europa must be relatively young?

15. Objects orbiting around the center of the Milky Way obey Kepler’s 3rd Law. This means that: