Introduction and Thesis
I had an argument with my friend before about whether the Earth or the Sun was the center of the Solar System. We were both really young, and there was still many things to learn about. So at that time I looked up the answer and all the information mentioned Galileo's name. Later on, I learned more about Galileo and the Copernican theory. As I learned about who Galileo was, I wanted to learn more about his telescope. So then with that, I chose for my research to be about his telescope and him agreeing with the Copernican Theory. From the research, I learned that with the help of his telescope, Galileo saw different phases of Venus and the moons of Jupiter which helped him prove the Earth wasn't center of the Solar System.
His telescope helped him prove that the Copernican Theory should be more accurate, thus he was accused of heresy two times by the Church for his beliefs. (Galileo and the Telescope, 2017) Galileo changed how people viewed the Solar system after, letting us know that the Copernican Theory should be more accurate. In 1609, he made the first refracting telescope out of glass lens. The telescope he made was 36.5 inches long, and is on a stand so it wouldn't shake when he is observing the space. (Galileo's Refractor, 2017) He figured out that when lenses are further away from each other, it would let him see close objects more closely. If the lenses have a shorter distance between each other, it would let him see faraway objects better. However, he died in prison without knowing that his theory would be accepted by many people and is correct. In fact, he was even made fun of before for believing the Copernican Theory since the Ptolemaic models were more popular in those days. They were used to believing that the Ptolemaic models were correct.
Evidence and Analysis
Galileo was an Italian astronomer and scholar born in 1564. He supported the Copernican Theory, and wrote books out of his observations of the space. In the Starry Messenger, Galileo sketches out his observations of the sky like the Moon's surface and the sun spots. This is important because his sketches are really detailed and he explains his observations.
With his telescope, Galileo was able to see different phases of Venus, and this was a very important discovery. In Ptolemaic models, the theory in which Earth is the center and the other planets orbit around Earth. Venus should always be between or remain between Earth and the Sun. This would mean, we should only be able to view the night side of Venus most of the times. However, Galileo saw different phases of Venus, and also the day-lit side of Venus. This indicates that Venus could be on the opposite side of the Sun from the Earth. (Brown, 2017) The Ptolemaic models don't have any way of accounting for these phases, since the phases of Venus are based on the planet's position relative to the Earth and the Sun. (Galileo, 2017) The phases could only occur if Venus was circling around the Sun, and not the earth.
Another discovery Galileo made was of the moons of Jupiter. One night, Galileo thought he saw stars around Jupiter. He then realized that the stars are actually going around Jupiter, and later he knew they were moons of Jupiter and that they orbit around Jupiter just like our Moon orbits the Earth. (Galileo, 2017) This helped form a major argument against the Ptolemaic models. It was the first time that objects had been seen orbiting around another planet, weakening the Ptolemaic models. This also meant that the Earth wasn't the only center of motion, since the moons orbited around Jupiter. (Galileo and the Telescope, 2017) Some supporters of the Ptolemaic models also say that if the Earth is moving through space, the moon would be left behind, but then Galileo's observations show that if Jupiter moves, the moons would not be left behind but actually still orbit around it as Jupiter moves.
Conclusion
To summarize, Galileo's telescope really helped Galileo prove that the Copernican theory should be more correct and that the Ptolemaic models weren't accurate. The phases of Venus and the moons of Jupiter were really good observations seen from his telescope that helped make the key arguments that the Ptolemaic explanations were wrong. They helped prove that the Earth couldn't be the center, therefore proving that the Ptolemaic system is inaccurate.
