Even after the birth of astronomy, humans did not immediately know that the planet they are living in is spherical. Originally, people thought that the sun and the other planets were orbiting around the earth. This theory, known as the Ptolemaic model or geocentric model, was replaced by the fact that all the planets are orbiting the sun called the heliocentric model by Nicolaus Copernicus, which was not immediately accepted at the time. In fact, its major adherents, Giordano Bruno and Galileo Galilei, were both persecuted by the Roman Catholic. However, Bruno and Galilei were not at the same path in all aspects in their endeavor to promote the Copernican heliocentric model of the solar system. Giordano Bruno is an Italian itinerant scholar who was once a Dominican.
In the same period, Bruno and Galilei were inspired by Copernicus and supported his revolutionary findings through their writings. After his astronomical observations of the phases of Venus and the moons of Jupiter, Galileo Galilei wrote a defense of the heliocentric system that led to his trial and house arrest by the papal Inquisition. In this defense, Galileo concluded that the Earth indeed moved and he was tortured into retracting it. Similarly, Giordano Bruno proposed that actually, the sun was merely another star that can be seen close up, and the other stars had their individual planets. Bruno fought for these findings, which were daringly revolutionary then, to the point that he was burned alive. The growing technology of the modern times validated these findings by Galileo and Bruno and refuted Aristotle and the Roman Catholic Church. Unfortunately, during the days of Galileo and Bruno, it was preposterous to declare that the Earth moves since most people believe that epicycles and deferents exist. The theories of a geocentric universe and the epicycles, according to Rivero, were not science but were only religious doctrines disguised as science (n.p.).
Indeed, it started with Nicholas Copernicus who had suggested the premise in a book he dedicated to Pope Paul III that the earth orbits around the sun and the core of the planetary system is the sun and not the earth. While both Giordano Bruno and Galileo Galilei were significantly influenced by Copernicus ‘writings, the approaches wherein they developed the radical premise of Copernicus were immensely different in many ways. Galilei, who has been frequently condemned for keep his own protection from his own troubles, never mentioned Bruno in his works, because they never met each other in person (Kessler n.p.). But the bottom line is that the modern earth owes the discovery of the heliocentric model of the solar system not only to Copernicus but to Galilei and Bruno, as well.
Kessler, John J. Giordano Bruno: The Forgotten Philosopher. Internet Infidels, 2012
Rivero, Michael. The “Big Bang” is Religion Disguised as Science. Whatreallyhappened Com LLC, 2012