* Nicolaus Copernicus: He challenged the geocentric model of the universe (Earth at the center) with his heliocentric model (Sun at the center). This shift, outlined in his book *De Revolutionibus Orbium Coelestium* (On the Revolutions of the Heavenly Spheres), sparked the Scientific Revolution.
* Isaac Newton: His work, most notably *Philosophiæ Naturalis Principia Mathematica* (Mathematical Principles of Natural Philosophy), laid the foundation for classical mechanics, describing universal gravitation and the laws of motion. He also made significant contributions to optics and calculus.
These two giants, along with others like Galileo Galilei and Johannes Kepler, drastically changed the way people understood the universe and the world around them.