Planets

Since ancient times five planets have been easily visible to the naked eye - Mercury, Venus, Mars, Jupiter and Saturn. They appear to us like stars, as bright points of light in our night skies. Planets charts humanity's understanding of our neighbouring bodies, from the first clues established by Galileo Galilei in the 17th century, through to the vast amount we do (and much we don't) know today. Planets is the second book in a series of accessible guides to astronomy, written by astronomers at the Royal Observatory Greenwich.