Galileo Galilei

Galileo Galilei was an Italian Great Thinker, who lived in and played an important role in the Scientific Revolution. He was also a polymath, which meant that he was very talented in mathematics, astronomy, engineering, philosophy, and physics. He was responsible for creating the Heliocentric theory, the idea that the Earth revolves around the sun. However, because of this discovery, he was put under house arrest for the rest of his life. However, while he was under house arrest, he wrote one of his best-known books, Two New Sciences, which was a summary on his work related to the two sciences now referred to as kinematics and strength of materials.

Galileo analyzed speed and velocity, gravity and free fall, the principle of relativity, inertia, projectile motion and also worked in applied science and technology, describing the nature of pendulums and "hydrostatic balances", inventing the thermoscope and various military compasses, and using the telescope for scientific observations of celestial objects. His contributions to observational astronomy include the telescopic confirmation of the phases of Venus, the discovery of the four largest satellites of Jupiter, the observation of Saturn's rings (though he could not see them well enough to discern their true nature) and the analysis of sunspots.

Sources/Citations
https://en.wikipedia.org/wiki/Galileo_Galilei