On August 25, 1609 Galileo first demonstrated the telescope to Venetian officials and then proceeded to point it at the night skies in order to study rather than speculate about what the heavens hold. He saw mountains and what looked like seas on the Moon. He saw the planet Venus going through phases like our Moon does. He saw the disc of Jupiter and four small satellites circling it.
These and other observations allowed him to prove, contrary to the Ptolemaic theory and Catholic Church doctrine, that the Earth is not the immovable center of the solar system and that the Sun holds that place. Galileo was also the first great experimental physicist. He ushered in the age of science in which we seek knowledge by starting with the evidence of our senses and rejecting unsupported dogma.
It is said that some religious clerics looked through his telescope and, rather than admitting that their dogmas were wrong, simply said, “I see nothing.” The Inquisition eventually tried Galileo and, under threat of torture or death, forced him to declare that he rejected his prior beliefs. On leaving the trial for house imprisonment for life, he supposedly remarked, concerning the Earth, “But it still moves.”
Whether these stories are apocryphal or not, they highlight the age-old struggle between those who use reason to gain objective knowledge of reality and those who reject reason in favor of a subjective feeling that reality can be whatever one’s ignorance wants it to be.
The science of astronomy since the time of Galileo has given us knowledge of the nature of the universe and continues to make more mind-expanding discoveries. So let’s remember that it takes a brave mind like Galileo’s to open new human horizons which are as large as our universe!