St.Peter Museum of Arts And Science

Presenting: Astronomers in the Renaissance

Exhibit Information:

The Renaissance was a period of growth and activity in the areas of literature, art, science, and ideas in Europe around the 16th and 17th centuries. Some of the greatest scientific advances during the Renaissance were achieved by astronomers such as Nicolaus Copernicus, Tycho Brahe, Johannes Kepler, and Galileo. Come learn more at the St.Peter Museum of Arts and Science.
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Nicolaus Copernicus (1473-1543)

Before the Renaissance, people believed in a geocentric universe, which is the belief that the Earth is the center of the universe. Copernicus was the first man to challenge the geocentric view of the universe. Copernicus used his observations and intuition and proposed that the sun was the center of the universe. This was called a heliocentric universe. Copernicus claimed that the Earth and the other planets revolved around the sun in a circular orbit. He also believed that the moon orbited around the Earth. In 1543, before his death Copernicus published a book, De Revolutionibus Orbium Coelestium, which explained his ideas and beliefs. Unfortunately, Copernicus did not have the tools or math to prove his theory and it was often disregarded by other scholars. His book was also banned by the Catholic Church since the church believed his ideas didn't align with theirs and that they were offensive to God.

Tycho Brahe (Finished Work in 1580)

Tycho Brahe was a Danish astronomer. The Danish King provided Tycho Brahe with an island and the finances to build and observatory and stock it with the finest equipment. Tycho Brahe admired Copernicus' ideas but he simply could not accept his heliocentric idea. Instead, Tycho Brahe claimed that the earth lay in the center of the universe. He believe that the moon and the sun revolved around the Earth and he also believed that the other 5 known planets revolved around the sun. Tycho Brahe proposed that the Earth was unmoving and fixed and he denied that idea that the universe was extremely large. Despite the inaccuracy of his theory, he still contributed to astronomy because he helped make extremely accurate measurements. He also employed an assistant, Johannes Kepler, who became one of the best atronomers ever.

Johannes Kepler (1571-1630)

Johannes Kepler helped take astronomy to the next stage by building upon the ideas of both Copernicus and Brahe. Johannes was an assistant to Tycho Brahe so that he could get access to the quality data that only Tycho Brahe could provide. When Tycho Brahe died, Johannes Kepler inherited Tycho's information. Johannes however did not agree with Tycho's beliefs in a geocentric universe. Instead, Johannes Kepler felt Copernicus' ideas were more suitable to the information he had. However, Johannes also had his own ideas about the universe. Johannes Kepler said that the universe was geometrically perfect, with all the planets and the stars moving in an ordered fashion. Kepler was the first to suggest that the planets did not orbit around the sun in a circle, but in an ellipse. This fit the data very well and he was able to describe his model mathematically, unlike Copernicus.


Galileo worked on his model of the universe around the same time that Kepler worked on his. They were not fully aware of each others work but they were both advocates of the heliocentric belief. Galileo believed in Copernicus' model. Galileo was trained in medicine and mathematics and was very good at building things. Many people believe that Galileo invented the telescope, but it is actually very unlikely that he did. However, it is extremely likely that Galileo used his craftsmanship to improve upon the telescope, using it to observe the universe in greater detail than ever before. Galileo was the first person to study the skies with a telescope. Using geometry, Galileo was able to improve telescopes and he made many new discoveries. Some of the discoveries were:

-Saw Milky Way was made of individual stars which means they are very far way.

-Saw that the Sun and Moon had features and irregularities. He discovered the moon had mountains and valleys and the Sun had sun spots.

-Saw that Jupiter had its own moons, with the inner moons revolving more quickly.

-Saw that Saturn had appendage, but his telescope wasn't strong enough to see the rings.

During Galileo's life he faced many problems with the Catholic Church, but by the time Galileo died many scholars accepted the heliocentric model and new discoveries sparked the interest in others to learn more.