Kepler's 'tunes of the planets', 1619.
© Science Museum / Science & Society Picture Library
German astronomer Johannes Kepler (1571-1630) believed each planet had its own tune that the planet 'sung' during various parts of its orbit. In this book, 'Harmonices mundi' (The harmony of the world), published in Linz, Austria in 1619, he shows the tunes of Saturn, Jupiter, Mars, Earth, Venus, Mercury and the Moon. Also in this book Kepler announced his third law of planetary motion, stating that the square of a planet's periodic time is proportional to the cube of its mean distance from the sun. Kepler's three laws formed the basis of Isaac Newton's discoveries. Wilhelm Schickard designed the woodcut diagrams and illustrations for this work.