Curiosity of a mankind toward heavens is as old as human civilization itself, if not older. We can find evidence of this fascination all over the world. During studying of my textbook I have realize that from dawn of time civilizations were attempting to map the stars. Some used obtained knowledge and applied it to more practical means such as farming and sea navigation. Some civilizations such Egyptians or Aztecs would use knowledge of the cycles of solar eclipses as political means, since they appeared to command the sun they would control it people. However, with every new discovery came more questions about the universe. With mere size of the universe, one might come to realization of amount of time required for its comprehension. Hundreds if not thousands of astronomers throughout the ages added some valuable pieces of information to astronomical big picture. As Cecilia Payne-Gaposchkin brilliantly putted in her 1976 speech " [...] The old scientist cannot claim that the masterpiece is his own work. He may have roughed of part of the design, laid on a few strokes , but he has learned to accept the discoveries of others with the same delight that he experienced on his own[...] (Astronomy Today, Chap. 16, p 383) What we know today about the universe is a collective work of many generation of dedicated man and woman who continue to add new insight of astronomy great spectrum of universe. Some scholars may add a little, some may add a lot, yet some may change our understanding of a matter in question. Such man were Copernicus, Galileo, Kepler and Newton. Those man are credited with revolutionizing the study of astronomy. The heliocentric theory formulated by Copernicus caused strong turmoil within astronomy, physics and cosmology. Many man of science considered it as contrary to Aristotle’s physics and the Bible. However, some astronomers were engaged in disputes concerning the importance of the discovery of this new system. The interest in astronomical observations caused by the presentation of Copernicus’s theory resulted in astronomical phenomena which became regarded as inconsistent with the scientific paradigm of perfection of celestial bodies, which had existed since ancient times. This debate would cause man of science to look toward the heavens. This in turn, would create more empirical data, such as one gathered by Brahe which had a crucial influence on Kepler, who in his four works formulated a new heliocentric theory. He based it on Copernicus’s basic hypotheses , on Brahe’s observations, and on the magnetic ideas of Gilbert. Due to scientific debate concerning Copernicus theory a modern physics was being formed – kinematics, dynamics, theory of gravity . Galileo Galilei brought astonishing input to the field of astronomy, while bringging a bit of embarrassment to the catholic church. All was sparked by dispute over two theories of our universe, the geocentric theory and the heliocentric theory. Contemporary science to Galileo, had no real scientific proof of either one. The geocentric universe was believed to be true, since it fit with the theology of Thomas Aquinas and most importantly the Bible. On the other hand heliocentric universe was put forth by Copernicus, who didn't reveal his ideas until he was on his death bed, in fear excommunication. Galileo, became a champion of heliocentric principle. He enhanced a Dutch spy glass, thus creating his own telescope. Which enabled him to discover sun spots and craters on the moon. Moreover he found four large moons of Jupiter. He also noted fazes of Venus, proving that it had to be moving around the sun as well as the earth. Due to his observation he deducted that the earth and the rest of the planets revolved around the sun. However, he and many other astronomers still thought that planets orbits were perfect circles. which is contrary with our understanding. The impact of Galileo's research is quite amazing. The Renaissance astronomer and astrologer Johannes Kepler is best known for his discovery of the three principles of planetary motion, by which he clarified the spatial organization of the solar system. Moreover, he founded modern optics by presenting the earliest correct explanation of how human beings see. He was the first to set forth accurately what happens to light after it enters a telescope, and he designed a particular form of that instrument. His ideas provided a transition from the ancient geometrical description of the heavens to modern astronomy, into which he introduced the concept of physical force. Kepler studied under Michael Mstlin, a professor who may appear to be unique in his day, because he was convinced that the astronomical system propounded by Copernicus was basically true. Kepler's youthful acceptance of Copernican astronomy greatly affected course of his life. Sustained by a vision of mathematical harmonies in the skies, a vision he derived from the philosophy of Plato and the mathematics of the Pythagoreans, Kepler tried to relate planetary orbits with geometrical figures. According to Copernican astronomy there were six planets, whose orbits were regulated by the turning of invisible spheres. Kepler also extended Copernicus' reasoning to the other planets and was the first to declare that the other planets resemble the Earth in being material bodies. Idea of alternating planets and regular solids constituted the main theme in Kepler's "Cosmographic Mystery". The Platonic and Pythagorean components in Kepler's conception of celestial harmony, helped to lead him to the three principles of planetary motion now known by his name. Kepler sent copies of his first major work to a number of scientists, including Brahe, who was soon to become the imperial mathematician of the Holy Roman Empire. Although Brahe did not agree with Kepler's theory, he was so impressed by the author's knowledge of astronomy and skill in mathematics that in 1600 he invited him to join his research staff. After Brahe's death, Kepler was appointed as his successor as. Kepler obtained access to Brahe's incomparable collection of astronomical observations, the result of decades valuable data by the greatest naked-eye observer of the heavens. Moreover, he made an analysis of the process of vision that provided the foundation for all of the advances in the understanding of the structure and function of the human eye. Kepler applied those ideas in explanation of the principles behind his telescope. In "Astronomia Nova", Kepler had demonstrated that the orbit of the planet Mars is an ellipse. Although it had been believed since antiquity that the planets, could move only in perfect circles. Furthermore, he concluded that the planets do not travel in a perfectly circular orbit, but they move in ellipses. In 1619, he published the "Harmonice Mundi", where he deliberated his third principle, which related a planet's mean distance from the Sun to the time it takes to complete its elliptical orbit around the Sun. Kepler's contribution to the understanding of planetary motion paved way for Newton's exposition of universal gravity, which affects all of the material bodies in the physical universe. Finally, Sir Isaac Newton who with his findings revolutionized science in general. He was an English mathematician and physicist who invented calculus. Moreover he is responsible for formulating the law of gravity and laws of motion. During his life time he investigated the nature of light, which led him to discovery spectrum of light. Newton also developed a reflecting telescope where he employed mirrors to solve the problem of chromatic aberration, in which the light from stars was surrounded by a spectrum of colors. Newton was the first person who managed to explain that periodic rises and falls of large bodies of water are caused by the gravitational interaction between the Earth and the Moon. During his famous stroll at his apple orchard, he have noticed an apple fall. This event caused a single though in Newton's mind, thus enabling him to unite the behavior of gravity on Earth with gravity in space. Newton concluded that gravity is a universal force that is found throughout the universe. Single fruit led him to the most important of all his works, the Law of Gravity where he describes the gravitational attraction between objects, where the force of their gravitational attraction depends only on their masses and the distance between them. Gravity is a fundamental constant of nature that determines the strength of the force of the gravitational interaction between objects. This extraordinary formula can be used to determine the mass of Earth or to determine interactions between celestial bodies. Moreover, This great scientist is responsible for "Three Laws of Motion" which greatly influenced physics and astronomy. As I have mentioned at the begging of my paper that astronomy is not work of one great man, but it is continually evolving. Each piece of information is added to the last, creating bigger picture. It allows us more comprehension of never ending, always expending universe. Sir Isaac Newton is my favorite example, since he was the one who by following the scientific journeys of Galileo and Kepler, formulated a great synthesis of terrestrial and celestial mechanics. I must state that he achieved a goal that had been sought by Aristarchus of Samos, Copernicus, Galileo, and Kepler. He is responsible for formulation of a unified theory of terrestrial and celestial phenomena and corresponds with the observations proving existence of the motions of the Earth.