Galileo Galilei was an Italian astronomer, mathematician, and a natural philosopher. Galileo was alive during the turning-point of science. His contributions to the areas of motion, astronomy, and the scientific method helped to change how we saw science. Galileo’s studies in parabolic trajectories, the law of falling bodies, and circular inertia started the beginning of foundationally altering the laws of motion. In his astronomical studies, Galileo revolutionized astronomy with his invention of the telescope. With the help of Galilei’s contributions, the road to the acceptance of Copernicus’s heliocentric system was created. Galileo was born on February 15th, 1564 in Pisa, Tuscany, Italy. Galileo was the eldest son of Vincenzo Galilei and Giulia di Cosimo Ammannati. Galileo’s siblings were Giulia, Michelagnolo, Livia, Benedetto, and Virginia. Vincenzo was a musician and made significant contributions to the theory of music. Between the age of four and five, Galileo’s father taught him about relation between pitch and tension in the instrument strings. In the beginning of the 1570s, the Galilei family moved back to Florence, where the family had lived for generation. There Galileo attended a monastery school at Vallombrosa during his mid-teens. In 1581, Galileo was registered at the University of Pisa. There he was intended to study medicine. But when while he was at the university, Galileo became engrossed in mathematics. After that, Galileo decided that the fields of mathematics and philosophy would become his future occupation. Vincenzo didn’t approve of this choice, but Galileo pursued what he loved despite the disapproval his father expressed. After his decision was made, Galileo started making preparations to teach mathematics and the philosophies of Aristotle. Galileo left the University of Pisa without his degree in 1585. After leaving the university, Galileo offered private lessons on the various fields of mathematics in Siena and in Florence. Galileo continued giving exclusive lessons for many years after he left the University of Pisa. In the years after the university, Galileo also studied the laws of motion. For weighing small masses, Galileo designed a new type of hydrostatic balance. Along with his design, Galileo wrote a diminutive thesis called La bilancetta. In 1588, Galileo attempted to apply for the chair of mathematics at the University of Bologna. His attempt was unsuccessful. In the following year, Galileo, whose statue was becoming more well-known, was asked to give two lectures at the Florentine Academy. In his two lectures, Galileo discussed the disposition of the world in Inferno by Dante Alighieri. Galileo also discovered some brilliant theorems on the center of gravity. His findings earned him respect from many mathematicians and the sponsorship of Guidobaldo del Monte, an author of many mechanical works and a nobleman. After receiving much recognition, Galileo earns the spot of head of mathematics at the University of Pisa. Unfortunately, Galileo lost this position when he disagreed and disproved Aristotle’s claim that when a heavy object is falling, the speed of that fall is not proportional to the object’s weight. Galileo demonstrated his thinking by releasing bodies of all different weights from the Leaning Tower of Pisa. Many saw that Galileo was embracing the Archimedean approach to this notion. Many of his colleagues found Galileo’s theories against Aristotle very unwelcoming. This caused Galileo’s contract as the head of mathematics at the University of Pisa to be left unrenewed in 1592. With the help of his patrons, Galileo found a new position as head of mathematics at the University of Padua. At the University of Padua, Galileo taught mathematics, physics, and astronomy. Galileo reamined the head of mathematics at Padua from 1592 up until 1610. During the mid 1500s to the early 1600s, England was currently in the Elizabethan era. A blossoming time for England. They were flourishing in the arts and their ruler, Queen Elizabeth I, was beloved by the people. Explorers were becoming successful and the very first theaters were being made. In Italy, Venice especially, they were recovering from the suffocation of war and rebuilding. Galileo has made many contributions to the world of science with his discoveries. For instance, Galileo was the first person ever to study space through a telescope. With his invention of the telescope, Galileo was able to discover many new things about space and our solar system. Galileo was also a skilled maker of telescopes so, he was able to make efficient telescopes and get the idea of a telescope out ot the public. Some of Galileo’s astronomical discoveries were that other moons that orbit other planets, besides Earth, existed. Galileo discovered Jupiter’s four largest moons: Europa, Io, Ganymede, and Callisto. These moons are in a group called the Galilean Satellites in honor of Galileo Galilei. He also found out that Venus goes through a cycle similar to our moon. This discovery was a major piece of evidence that helped to support Copernicus’ idea of a heliocentric solar system. Galileo discovered that Saturn had rings. He also discovered that the moon has mountains. Galileo also found out that Milky Way is consisted of million of stars. Galileo was the first person to ever see Neptune. In his notes, Galileo described that Neptune was moving, unlike the other stars he had recorded. Galileo’s discoveries regarding gravity were that if there is no air resistance then, every object would fall at the same rate, despite having different masses. Meaning that, gravity accelerates every object equally. Galileo also found out that gravity accelerates any object at a constant rate, making the distance that the object has fallen is corresponding to the time fallen squared. Galileo discovered that anything that was shot from Earth, moved along a curved path. The shape of the curved path is parabola. Galileo gave us the basis of inertia. Which was how Sir Isaac Newton created his first law of motion. Galileo also aspired the first theory of relativity. Galileo attempted to measure the speed of light, but found that it was much too fast for him to take accurate measures of it. In the area of mathematics, Galileo discovered that there was a flawless set of numbers(1, 4, 9, 16, 25, 36, 49, 64, 81, 100, 121, 144 . . .) that contain as many numbers as the basic counting system that we use. This is known as Galileo’s Paradox. It states that there must be as many whole squared numbers as there are whole regular numbers. Every whole number can be squared, so every squared number can also be matched up with its square. Some of Galileo’s discoveries were accepted and appraised from his fellow scientists and colleagues, but other times Galileo’s discoveries weren’t accepted by scientists, despised even. Galileo lost his job because, of fellow scientists not accepting his revolutionary discoveries. Some scientists didn’t like how some of Galileo’s discoveries disproved the ideas from scientists long ago.Then there were other scientists that appreciated and accepted Galileo’s discoveries and ideas. Galileo was known to have multiple patrons when he was in his late twenties. Galileo was the head of mathematics in two universities in Italy, because his discoveries were accepted. Galileo openly stated that the Bible was wrong in a few of his published works. This caused him to receive hatred from the Church. Also saying that he agreed with Copernicus’ heliocentric theory, earned Galileo certainly no love from the Church. For example, in 1632, Galileo’s latest work, Dialogue Concerning the Two Chief World Systems, was approved for publication by the Church in Florence. Rome didn’t approve, and a year later Galileo is called to Rome for charges of heresy in Dialogue Concerning the Two Chief World Systems. Galileo was interrogated and threatened with torture. Galileo was charged with a lifetime in prison, but his charges were reduced to house arrest mostly due to his old age at the time. The Catholic church banned all of Galileo’s work, as well. Though in countries where the Catholic church had less power, Galileo’s works were permitted for anyone to read. Galileo’s discoveries were revolutionary to science, and the world. Galileo made it possible for astronomers, scientists, and all people to see into space from Earth with his invention of the telescope. What Galileo discovered in space, changed what everyone had thought to be true about space and our solar system. How the world, and what lies beyond it, was perceived forever changed with the discoveries made by Galileo Galilei. Galileo’s discoveries in other fields besides astronomy changed science forever. Galileo created the foundation for inertia and the first theory of relativity. With these discoveries, future scientists, such as Sir Isaac Newton and Albert Einstein, were able to discover new things in science using what Galileo had previously found. The impact of Galileo’s discoveries came while he was alive. Galileo’s invention of the telescope and what he had discovered with it were transforming astronomy and everyone’s belief of what lies beyond in space. With his telescope, Galileo discovered details in Earth’s moon, Jupiter, and Venus that nobody had ever been capable of seeing before. Galileo’s discovery that Aristotle was wrong about the speed of a heavy object fall being proportional to the object’s weight. Yet, some of Galileo’s discoveries had impact after his death. When Galileo discovered Neptune for example. Nobody really knew the impact of this discovery. Everyone during this time thought that the last planet in the solar system was Saturn. And, Galileo’s basis of inertia and the theory of relativity had more of an impact later on when other scientists expanded on these concepts. Galileo Galilei revolutionized how the world and science would be seen forever. He discovered many things that helped us progress to where we are today in science. The contributions of Galileo were crucial in the advancement of our knowledge of our own solar system and space. Galileo suffered for believing and discovering what he believed. Without his loyalty to his work and discoveries, we might be able to understand the vastness of what he discovered today.