The Sun For much of human history many people believed Earth was fixed in the center of space They thought the other planets and the sun revolved around it This concept is now known as the geocentric model Thinkers such as the Greek scholar Ptolemy who worked in the 100s CE were strong supporters of this idea Early thinkers believed Earth was at the center of the universe 8
Copernicus challenged existing notions of the structure of the universe Things began to change in the 1500s The Polish scholar Nicolaus Copernicus proposed the idea that the sun was at the center and Earth was simply one of several planets revolving around it This concept is the heliocentric model It came into conflict with some religious teachings relating to the nature of the sun and Earth For decades after Copernicus published his idea it was not widely accepted 9
mid The Sun The Italian astronomer Galileo Galilei revisited the idea in the early 1600s The concept of heliocentrism soon reached a much broader audience Religious authorities banned Galileo’s book and punished him But new observations by Galileo and other scientists provided more evidence for the heliocentric model By the 1600s most astronomers supported this idea Artwork depicts the trial of Galileo for supporting concepts that went against religious authorities 10
Centuries after his death Galileo was honored with the naming of the Galileo probe which explored Jupiter 11
