Why is it appropriate that galileo galilei is known as a leader in the study of space

Back in 1615 when it was widely accepted that the earth was the center of the galaxy, Galileo discovered that we revolved around the sun in year long cycles along with other planetary objects. He was put in house arrest for 9 years because of this because it was considered a heresy. He also invented the telescope and was the first to observe the largest of Jupiter's moons.