Few inventions in science arise out of whole cloth; mostly, they are just gradual adaptations, improvements, additions to the theme. Galileo did not invent the telescope, contrary to popular belief – Hans Lippershey filed a patent for one in 1608, which was rejected by the Estates-General with the explanation that the idea was already too common to be granted a patent. The following year Galileo created his first telescope, imitating the ones found all over Europe, but he added to them lenses capable of 20x magnification, far superior to the 3x around at the time. Then he used them to challenge popular convention.

On this day, November 3, in 1609, Galileo Galilei made his second sketch of his observations of the moon through his 20x telescope. In his findings, the moon was far from the perfect sphere it was conceived to be.

The moon, according to Galileo’s Sidereus Nuncius (“Starry Messenger”), published in 1910, was pockmarked and cratered. The moons of Jupiter orbited around the planet, not around Earth, as the Catholic doctrine held. Numerous other stars were found, unseen with the naked eye. Galileo’s public contradictions of the Pope’s teachings did not win him any friends in the Vatican, but they were an important step in creating the modern science of astronomy.