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Galileo's First Look
Galileo Galilei was the first scientist to use a telescope to look up. What he saw was important because it disproved the notion that everything revolved around Earth. It was thought that Earth was at the center of the Universe and that everything revolved around it. Galileo made many important observations that helped to disprove this. Among other discoveries, he saw that Venus had phases like Earth's Moon. This suggested that Venus was revolving around the Sun, not Earth. He also saw that Jupiter had four moons revolving around it. Galileo saw a lot more stars than are viewable from Earth, and examined the crater-spotted surface of our Moon. Galileo's observations laid the groundwork that helped Newton develop his theories of motion—laws that explain how different bodies move. Galileo's observations are still repeated by many amateur astronomers today.