By the time he died, this week (Jan. 8) in 1642, in Arcreti, Italy, Galileo Galilei had fathered as many fields of science as he had children. In addition to fathering three (illegitimate) offspring, this pioneering scientist, mathematician and astronomer is today referred to as the “Father of Modern Observational Astronomy,” the “Father of Modern Physics,” and the “Father of Science.”
Galileo was the first scientist to use the telescope to make a prolonged study of our celestial bodies, the result of which was publication of his first important paper (a late bloomer, he was 46 at the time). Titled “The Starry Messenger,” it astonished the scientific community because it announced, for the first time ever, that there were mountains and craters on the moon, that the planet Jupiter has four moons, that there are rings around Saturn, and that the Milky Way comprises many millions of stars.
Yet it was his later discovery of the “phases” of Venus — its progressively changing shapes (like the phases of our moon) — that revolutionized both scientific and religious theory. For the fact was, seeing those different phases from the vantage point of Earth was only possible if Venus revolved around the Sun, and not the Earth, as was thought at the time. Both the scientific community, and especially the religious community, believed in “Geocentrism” — the theory that the Earth was the center of our galaxy, and the Sun and the planets revolved around it. Yet Galileo’s findings confirmed the conclusion the astronomer Nicolaus Copernicus had made 100 years earlier, that “Heliocentrism” (sometimes called “Copernicanism”) — meaning the planets revolved around the Sun — was the correct belief.
Galileo published those findings in his controversial “Dialogue on the Two Chief World Systems,” in which, under pressure from the Catholic Church, he had agreed to stay neutral as to which system, Geocentrism or Heliocentrism, was correct, but his actual text clearly advocated the Heliocentric theory. When the Catholic hierarchy learned of this heretical double-cross, Galileo was ordered to Rome to face the Inquisition, and after a trial in which, after initially denying it, Galileo finally admitted that any fair reading of “Dialogue” would lead to the conclusion that Heliocentrism was the proper belief, he was found guilty of heresy. He was sentenced to life in prison, but given his age, health and reputation, his sentence was commuted to life under house arrest.
It was a remarkable life all the same, for Galileo, in addition to his many contributions to mathematics and general science, is the man who gave observational astronomy a legitimacy and seriousness — he made it an actual science — that has led to a much better understanding of both our solar system and our universe.
