Galileo was the first to observe the heavens with a telescope, seeing that mottlings on the moon were ridges and troughs on the lunar surface, observing the passage of the inner planets around the Sun - instead of the Earth, as written by Copernicus - and noting the clockwork-like motion of moons around Jupiter. WHAT GALILEO SAW was supported by Kepler and other seventeenth-century philosophers to spark the Scientific Revolution. What people had believed for so long turned out to be inaccurate, now that instruments of observation and methods of study were available. But saying so was denounced as heresy.

This presentation of the times delves into the philosophy and poetry of 1610 when Galileo's notes were first made public, and the dogma controlling society. The established religious were wealthy and powerful, and they feared losing power if they were proven to be incorrect. Poets from the Ancient Greeks to Milton, who quoted the Greeks, wrote of what they saw in the stars and of what the constellations represented. Mingling truth with fancy was a regular occurrence; Kepler arranged planetary orbits according to five Platonic solids and heavenly music of the spheres. Yet he did construct three correct laws regarding the solar system.

Galileo's father was a professional musician who studied the theory of music, passing on lessons to his son in Florence. The young man liked practical experiments to test his theories and took the chair of mathematics in Padua in 1592. Having heard about a spyglass that brought distant objects closer in vision, he ground his own glass lenses to make his version, adding magnifying equipment of his own design. Then he looked at the moon. His drawings are reproduced in this book. Having observed what he took to be fixed stars near Jupiter, over two months of sketching he was astonished to find that they moved around the large disc.

Lawrence Lipking has presented his interesting tale in scholarly fashion, with many quotations from letters of the day and appendices, so this will not suit young readers or those who want a brief guide to astronomy. WHAT GALILEO SAW is intended as a history and philosophy guide, asking us why we believe what we believe and demonstrating that one brave man who was condemned to imprisonment, changed our minds.