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Natural Philosophy (Former Science) before 17th century The Earth is considered the center of the universe, with all celestial bodies rotating around it. The laws governing the heavens differ from those on Earth. The Earth is viewed as imperfect, and changes occur as a result of this imperfect...

Natural Philosophy (Former Science) before 17th century The Earth is considered the center of the universe, with all celestial bodies rotating around it. The laws governing the heavens differ from those on Earth. The Earth is viewed as imperfect, and changes occur as a result of this imperfection. Change is understood as the process of potential states becoming actual states; however, merely having potential is insufficient for change without actualization. The heavens and stars are considered perfect and unchanging, moving in perfect circular paths and made of a distinct material called the “fifth essence.” The Earth is only a few thousand years old. All materials on Earth consist of four elements: air, water, fire, and soil. Life is believed to have evolved from non-living materials through a process known as spontaneous generation. Sunlight is described as white, pure, and homogeneous, meaning it is composed of the same substance throughout. Science and Religion Medieval theologian (Thomas Aquinas) (1225-1274) integrated the Aristotle view in harmony with Christian ideology. Scientific ideas become part of religion believes New Astronomy and Physics The geocentric model, where Earth is at the center of the universe and heavenly bodies move in perfect circles around it, faced problems, such as the gradual change in the positions of stars over time. The spring equinox, which occurs around March 20 or 21, is significant for astronomers because it marks the day and night being equal in length. However, the stars appear in slightly different positions each year on this date, challenging the idea of perfect circular motion. This phenomenon is known as the precession of the equinoxes, leading astronomers to conduct complex calculations for explanations. Ancient astronomers recognized seven planets: Mercury, Venus, Mars, Jupiter, Saturn, the sun, and the moon, but observed that their movements were not constant and sometimes appeared to reverse. The idea of placing the sun at the center instead of Earth raises questions about the implications of such a shift. Nicholas Copernicus, a Polish priest, boldly proposed this heliocentric model, suggesting that the planets, including Earth, revolve around the sun. Nicholas Copernicus : Nicholas Copernicus (1473–1543) was born and died in Poland, studying law and medicine in Italy. In 1514, he wrote a short manuscript stating that the Earth is not the center of the universe and that it revolves around the sun, but he did not publish it. Copernicus excelled in analyzing the observations of other astronomers and proposed that placing the sun at the center would clarify many astronomical difficulties. He calculated the approximate distances from the sun to the planets and from the moon to Earth, revealing that the universe was larger than previously thought. In 1542, he completed his significant work, De revolutionibus orbium coelestium (Revolutions of the Heavenly Bodies), but was too ill to publish it himself, so he entrusted the task to his friend Rheticus. The book was published by Andreas Osiander, who added an introduction claiming Copernicus’s ideas were merely a potential solution to existing problems with the geocentric model, not necessarily true. Osiander’s preface misrepresented Copernicus’s views, leading readers for nearly a century to believe that Copernicus was only theorizing without asserting that the Earth orbits the sun. Kepler: Johannes Kepler (1571–1630) proposed that planets move not in perfect circles but in ellipses, which are flattened circles. His laws demonstrated that the ancient belief in perfect circular motion of celestial bodies was incorrect. Giordano Bruno: Giordano Bruno (1548–1600) moved to London in 1583 and gave lectures in Oxford about the Copernican theory of a sun-centered universe, which were met with hostility. While in London, he wrote satirical works and published his book “Dell’ Infinito, universo e mondi” (“Of Infinity, the Universe, and the World”) in 1584. Bruno defended Copernicus’s sun-centered theory and argued that the universe is infinite, containing an infinite number of worlds, all inhabited by intelligent beings. He was arrested in Italy and, on February 19, 1600, was publicly executed by burning in Rome. A statue of Bruno now stands in Campo de’ Fiori square in Rome, commemorating him. Galileo Galilei : Galileo Galilei (1564–1642) was born in Pisa and was very interested in experimentation. One of his early experiments showed that a ten-pound ball and a one-pound ball would hit the ground at the same time, contradicting everyday experience.  During this period, the telescope was invented to help view distant objects. Galileo transformed it into a powerful scientific tool. In 1609, Galileo learned about the telescope, pointed it toward the sky, and discovered that the moon wasn’t perfectly smooth but had mountains and craters. He also discovered that the planet Jupiter had moons, just like Earth has a moon. His telescope revealed that the Milky Way, which appeared as a fuzzy band of light to the naked eye, was actually composed of thousands of individual stars, far away from Earth. He published these discoveries in his book, “Starry Messenger” (1610), which caused a stir. Galileo’s observations were strong evidence supporting Copernicus’s theory that the Earth and other planets orbit the sun. In 1615, Galileo sought permission from the Church to teach what he had learned, but he was still forbidden from teaching or writing about Copernicus’s system. He wrote the “Dialogue on the Two Chief World Systems”, structured as a conversation between three people representing Aristotle, Copernicus, and a neutral host. It was clear from the dialogue that Galileo supported Copernicus. The publication of the book was delayed as the Church in Rome wasn’t pleased. In 1633, Galileo faced a trial, and after three months, he was forced to recant and declare that the Earth does not move and is the center of the universe. According to legend, after his conviction, Galileo muttered the famous words: “And yet it moves”. Although the Church had the power to imprison or torture him, Galileo’s reputation led them to place him under house arrest instead. Francis Bacon (1561–1626): Bacon was passionate about science, conducting experiments and observing nature. He is known more for his advocacy for science than any specific discovery. Famous for the phrase “Knowledge is power,” he argued that science is key to understanding and controlling nature. Suggested that scientists should form societies to share ideas and observations. Emphasized the importance of using precise language in science and approaching investigations with an open mind, avoiding preconceived ideas. Advocated for science based on experimentation and observation rather than authority. Highlighted the need to repeat experiments to ensure accuracy, promoting the method of induction to derive general laws from observations. Rene Descartes (1596–1650): Descartes believed that true knowledge could only be achieved by doubting everything and starting fresh, dismissing established authorities like Aristotle. He took a more solitary approach to scientific inquiry compared to Bacon, who envisioned science as a collaborative, state-funded enterprise. Both Bacon and Descartes believed that science was a special activity, distinct from everyday life, and that it had the power to improve human understanding and contribute to the public good. Isaac Newton (1642–1727): Newton’s most significant years of discovery were 1665 and 1666. Building on the work of Galileo and other scientists, Newton advanced mathematics, using it effectively in his scientific research. He made important discoveries in light and other areas of physics. Newton was a poor teacher; students often found his lectures hard to follow, and sometimes no one showed up for his classes. By the mid-1680s, Newton’s work in mathematics, physics, and astronomy was gaining recognition. His greatest work, “Mathematical Principles of Natural Philosophy” (Principia), outlined his three famous laws of motion: 1. A body remains at rest or in uniform motion unless acted upon by a force. 2. A force can change the direction of a moving object. 3. For every action, there is an equal and opposite reaction. These laws unified earlier scientific discoveries and explained phenomena from planetary movements to the trajectory of an arrow. Newton’s laws allowed people to see the universe as a giant, orderly machine, similar to a well- functioning watch. He provided both mathematical and physical explanations for the motion of planets and the force of gravity on Earth. Newton’s study of light: Ancient belief held that sunlight was white, pure, and homogeneous, and that colors were caused by modifications of this pure light. Newton studied Descartes’ work on light and conducted experiments of his own using lenses and a prism to break up light. It was believed that light traveled at infinite speed. Newton’s famous experiment involved allowing a tiny beam of light into a dark room through a prism, projecting a multicolored band on the wall, which helped explain how rainbows are formed.