The Solar System Author:Alexander Gordon Smith 128 pages. Nine planets and countless other objects revolving around our Sun make up the solar system As astronomers discover more about these heavenly bodies, including our own planet, Earth, they are also finding further mysteries and extraordinary space puzzles. But our solar system is just one of billions in the vastness of our galaxy, the M... more »ilky Way. And the universe itself contains countless ever-changing galaxies.« less