It's the birthday of astronomer Johannes Kepler, born to a poor mercenary in Wurttemberg, Germany (1571), who tracked the orbital path of Mars and published his three famous laws of planetary motion — which validated Copernicus's theory of a sun-centered solar system — and later helped discover the law of gravity. Kepler was nearly blind from a smallpox epidemic when he was three, and he developed the first eyeglass designs for nearsightedness and farsightedness. He was also the first to explain that the tides are caused by the moon, the first to propose that the sun rotates on an axis, and the first to use planetary cycles to calculate the year of the birth of Jesus Christ.
It was on this day in 1831 that Charles Darwin (books by this author) set sail from England on the HMS Beagle. Darwin's biology professor had recommended that he go on the upcoming voyage touring the Galapagos Islands and South America, but his father was against the dangerous trip. Darwin went anyway, and he explored the rainforests and was amazed by the plants and animals that he found. He returned to England, and he thought about what he had seen and developed his theory of evolution. In his book On the Origin of Species (1859), he wrote, "Probably all organic beings which have ever lived on this earth have descended from some one primordial form, into which life was first breathed. There is grandeur in this view of life that... from so simple a beginning endless forms most beautiful and most wonderful have been, and are being evolved."
It's the birthday of the father of bacteriology, Louis Pasteur, born in (1822), whose discoveries in germs and disease are why we now wash our hands before dinner.
-The Writer's Almanac