During the Renaissance people began once again to explore and experiment with the world around them. One area of science which made great leaps during this time was astronomy. Astronomy is the study of celestial bodies in outer space such as the Moon, the planets, and the stars.
Galileo demonstrating the telescope by H. J. Detouche
Earth as the Center of the Universe
For almost 2000 years the people of Europe had relied on the discoveries of the Ancient Greeks. Greek scientists such as Aristotle and Ptolemy had produced theories that the Earth was the center of the Universe. They said that the sun and the planets orbited around the Earth. People considered this as a fact for all that time.
Astronomer Nicolaus Copernicus put forth a new theory during the Renaissance. He said that the Sun was the center of the universe and that the Earth and the planets orbited the Sun. Of course, he was right about the Earth and the planets orbiting the Sun, but very few people believed him!
Galileo was one of the greatest scientists in history. A lot of his scientific work was in the area of astronomy. Galileo was already interested in studying the planets when he heard about the concept of the telescope. He improved the telescope and constructed one that could be used to observe the planets.
Galileo by Ottavio Leoni
Using his telescope, Galileo was able to make all sorts of new discoveries. He found out that the Moon was not really smooth, but covered with craters. He also thought that the moon didn't make its own light, but reflected light from the sun. Other discoveries included the moons of Jupiter, the phases of Venus, and sunspots.
Galileo Agrees with Copernicus
After recording and studying his observations of the planets and the moon with his telescope, Galileo believed that Copernicus' theory of the planets, including the Earth, rotating the Sun was correct. He wrote a famous work that explained why he thought this was the case. The Catholic Church did not agree, however, and put Galileo under house arrest.
Tycho and Kepler
Two other major astronomers from the Renaissance were Tycho Brahe and Johannes Kepler. Tycho was a Danish nobleman who took many precise measurements of the planets and stars over a long period of time. Tycho made many strides in the work of observing the heavens.
Kepler was a German astronomer who worked as Tycho's assistant for a time. Kepler developed the three laws of planetary motion and supported Copernicus' view of the planets orbiting the Sun. He also charted the orbit and position of many of the planets showing that they did not need to orbit the sun in a perfect circle.