He suffered an attack of smallpox when he was 4-years-old, which left him with crippled hands and poor eyesight. Overcoming those handicaps, he studied Copernicus' works and at age 23 became a professor of astronomy. His name was Johannes Kepler, born this day, Dec. 27, 1571. His laws of planetary motion, known as Kepler's Laws, helped Newton formulate the theory of gravity. Regarding his book on astronomy, Kepler stated: "O, Almighty God, I am thinking Thy thoughts after Thee! ... The book is written to be read either now or by posterity, I care not which. It may be well to wait a century for a reader, as God has waited 6,000 years for an observer."