Galileo had a serious tussle with the Catholic Church, but he also provided decisive evidence in favor of the Copernican model. So by the end of Galileo's life, it was widely accepted, that the earth was not the center of the universe. This was a seismic shift, which was the reason for the push back from the Catholic Church. Tussles between science and religion have continued through the centuries with some even in our present day. To put an exclamation point on this little saga of conflict between science and the Church, let me talk about the story of Giordano Bruno. Bruno was a mystic. It's probably inappropriate to think of him as a martyr to science or as a scientist in general. His ideas were not coherent the way Galileo's were. But he did indeed hold modern ideas of an infinite universe, of many worlds, of life on those worlds that he could include intelligent life like humans, so strikingly modern in his ideas. He was prosecuted by the Inquisition for heresy. In fact, the charge sheet against him declares him an impenitent and proteinaceous heretic. He was convicted, and in 1600, he was executed in the Campo de' Fiori. A statue there commemorates him. We can visualize the unfortunate and graphic scene. He would be paraded around the Campo de' Fiori in the back of an ox cart, covered in dung and straw to humiliate him, naked, with children laughing, and singing, and playing. These were festival days in Italy or any place public executions took place. He would have been strapped to the stake on top of a pyre. We know from records of the time that a soldier leaned in and to stop him spouting heresy as he died drove a spike through his tongue into his jaw. Another soldier however as a penitence, leaned in and hung a bag of gunpowder around his head to speed his demise. That was the death of Bruno 30 years before Galileo was brought in front of the Inquisition. Not to end on a sour note, relative to the Catholic Church, I will mention that I have for 30 years myself collaborated and been friends with the Vatican Observatory Astronomers who live and work at Steward Observatory and in Rome, and they've hosted me. So it is not simply true that the Catholic Church is against astronomy. We have cosmologists and astronomers working on astrobiology, my friends and colleagues. So I don't personally think that the science-religion debate has to involve conflict. From Galileo, from Brahe, from Bruno, and from Kepler, and from Copernicus before them, we have the basis of modern astronomy. We have the idea of the earth as just one of many worlds in space. In fact, Kepler took this and ran with it writing a book called Somnium, which is probably 400 years ago, the world's first science-fiction book about life on the moon, somewhat fanciful and not really realistic, but science fiction nonetheless. Of course, eventually, in the hands of Newton with the idea of space travel and the means to get to these other worlds. So by the end of the Copernican Revolution, our view of the universe has been transformed. We've now seen what I'll call the first step in a continuing Copernican Revolution. Conceptually, the history of astronomy to the present day is a displacement of humans and the earth in importance in the universe. It starts dramatically with the Copernican Revolution, which causes cultural and social upheaval as well, but continues in material we'll talk about later, where we discover the location of the earth in a vast system of stars called the Milky Way. Then, within the last century, the location of that Milky Way within a vast universe of galaxies in the observable universe. The Copernican Revolution potentially has two further steps to play out. One would be the demonstration that life on earth is not unique, that we live in a biological universe. The other from a frontier idea in cosmology, is the idea that the entirety of space and time, visible to the limits of our telescopes is not the totality of space and time, that there are other universes out there.