Major Contributions

As we move away from Galileo's life and into his contributions to the sciences, it must be reminded that his intentions were not to defy the Church but to correct the view of the universe.




His major contributions were to the fields of physics, astronomy, cosmology, mathematics, and philosophy. His overall larges was by far the Copernican Theory where the Earth is not the center of the solar system. Paired with that was the ability to view phases of Venus, moons of Jupiter, the rings of Saturn, sunspots, and the lunar surface. This was all possible due to his improved telescope. In 1609 he built upon a Dutch telescope and in 1610 discovered new "stars" orbiting Jupiter. These later turned out to be the four largest moons of Jupiter. With this discovery he published "Siderius Nuncius" (The Starry Messenger) which also contained his observations of the surface of the moon along with multiple other starts throughout the Milky Way.


From this publication, Cosimo II de Medici appointed him mathematician and philosopher to the Medicis of Tuscany. This gave Galileo a place to push his theories and challenge his opponents. Because his observations and theories contradicted the Aristotelian view of the universe, he ran into the issues previously discussed. Further, the description of the moon in Siderius Nuncius was rough and rugged, which also went against the idea of heavenly perfection.

Another of his great contributions is his study of force. During his time at the University of Pisa, it is said that he dropped two spheres of different masses from the Leaning Tower of Pisa to demonstrate that their descent time was independent of their mass. Supposedly from this, Galileo discovered that objects fall with the same acceleration, once again going against the Aristotelian theory of gravity. This new hypothesis, that objects do not fall at a speed proportional to their mass, was outlined in his book "On Motion."

From Galileo's motion experiments, Isaac Newton built his works on motion and force. And even against the will of the Church his heliocentric view of the solar system became accepted as scientific fact (with modifications by Kepler.) Other smaller inventions include improved compasses and balances, modified and improved telescopes and microscopes, all revolutionized astronomy and biology. 
Due to bringing the beginning of change for several fields of sciences, Galileo has been considered the father of modern science.