The idea that the earth's gravity is the cause of objects falling to the ground was not new: even the ancients, for example, Plato, knew it. But how to measure the strength of this attraction? Is that power the same everywhere on Earth? — these questions have puzzled, pondered and doubted scientists and philosophers alike since Newton, the author of the Universal Law of Gravitation.
When Kepler discovered his third law, he found himself in such a situation that he began to doubt whether he was right. In 1619 Kepler published in his famous work "The Harmony of the Structure of the Universe", partially answered these questions and came very close to discovering an important law. But he could not draw a completely rational conclusion from the considerations he made. In addition, Kepler attributed the motion of the planets to some mutual gravitational forces, and was ready to accept the law of "quadratic proportions" (that is, the effect is inversely proportional to the square of the distance). But he soon abandoned this law and concluded instead that the force of gravity is inversely proportional to the distance between the planets, rather than to the square of the distance between them. Kepler did not have the opportunity to scientifically substantiate the laws he discovered, which relate to the mechanical basis of planetary motion.
Newton's direct predecessors in this regard were his compatriots - Gilbert and especially Hooke. In 1660, Gilbert published a book entitled "On the Magnet". In it, Gilbert describes the properties of magnetism by analogy with the gravitational phenomena between the Moon and the Earth. Another work published posthumously by Gilbert notes that the Moon and the Earth exert an influence on each other like two magnets, and that this influence is proportional to their masses. However, Newton's contemporary and rival in scientific activity was Robert Hooke, who came closest to the scientific truth. On March 1666, 21, that is, shortly before Newton first delved into the mysteries of celestial mechanics, Robert Hooke published his paper "The variation of the force of gravity of a falling body with respect to its distance from the center of the earth." He presented his research at a meeting of the Royal Society in London. realizing that the results of his preliminary studies were unsatisfactory, Hooke decided to determine the force of theft by means of pendulum oscillations. This idea was the product of a high level of intelligence, and the scientific effect was also on this scale. Two months later, in another speech at the same meeting, Hooke suggested that the force holding the planets in their orbits must be similar to the force that causes a pendulum to swing. Much later, when Newton was preparing his great scientific work for publication, Hooke independently came to the idea that "the force which governs the motion of the planets must be measured in some relation to the distance" and describes the overall picture of the "Universal Law of Motion". . But here is the difference between talent and genius. Hooke's conclusions remained in the bud, and he did not have the opportunity to work with his ideas and hypotheses to the end. Newton was the author of the great discovery.
Isaac Newton (1642-1726) was born in Woolsthorpe, Lincolnshire. His father died before Newton was born. Sources say that her mother, who was traumatized by her husband's death, went into labor prematurely and gave birth to Newton prematurely. Born prematurely, Newton was extremely small and weak as a baby. Despite this, Newton lived a long, healthy life with only occasional short-term illnesses. According to their economic status, the Newton family belonged to the middle class and was engaged in farming. When Isaac reaches his teenage years, he is sent to elementary school. At the age of 12, Newton began attending a public school in Ganteme. During his studies, he lived in the household of Clark, a local druggist, for 6 years, and it was there that Newton's interest in chemistry began. On June 1660, 5, when Newton was not yet 18 years old, he was admitted to Trinity College. At that time, Cambridge University was one of the most prestigious centers of science in Europe, where teaching of philology and mathematics was equally highly developed. Newton focused on mathematics. But at the same time, in 1665, he received a bachelor's degree in Fine Arts (linguistics).
His first scientific research is related to the study of light. The scientist proved that it is possible to show the white color with the help of a prism. Observing the phenomenon of refraction of light in thin films, he observed a diffraction pattern called "Newton's ring".
In 1666, an epidemic broke out in Cambridge. The outbreak was widely believed to be a plague, social unrest and panic spread among the people, and Newton was forced to temporarily return to his native village of Woolsthorpe. . He lived in rural conditions, without any literature and tools, and in almost secular conditions. 24-year-old Newton at this time was completely immersed in the ocean of philosophical and logical thinking. He spent a lot of time with philosophical observations about the mysteries of the universe, the universe, the earth, time, and the psyche. The greatest product of this thought and reflection—his greatest discovery—was the discovery of the Universal Law of Gravitation.
It was a summer day. Newton liked to sit in the garden, outdoors, and think. It was then that a well-known and famous event, known to all of us from the school physics course, fell on Isaac Newton's head when a ripe apple broke off from the band. The apple tree that gave wings to this idea has been passed down from generation to generation as a symbol of pride of the Newton family for many years and has been preserved as a value. When the clock reached its time and dried up, it was cut down and a historical monument in the form of a chair was made from its wood.
Newton had been thinking about the laws of the process of objects falling to the ground for a long time, and the apple that fell on his head prompted him to think more deeply about this idea. Because of this phenomenon, he asked himself a new question: is the fall of objects on the ground the same everywhere on the globe? That is, is it possible to confirm that the body falls to the ground with the same speed in high mountains as in deep mines?
But in what way did Newton discover this fundamental law, stimulated by the fall of the apple?
In one of Newton's thoughts written many years later, he derived the formula for the mathematical expression of the law of gravitation from Kepler's famous laws. Also, in this regard, the effectiveness of Newton's scientific research, his personally conducted research in the field of optics in the directions of "light power" or "illumination level" gained importance. The mathematical formula of the physical law expressing "luminosity" or "illumination level" is very similar to the formula of the law of gravitation. Simple geometric concepts and direct experience show that, for example, if we move a piece of paper exposed to the light of a candle by twice the distance, the level of illumination of the surface of the piece of paper will not be doubled, but completely. rt decreases by a factor of three, if we move away three times, the illumination decreases by a factor of nine, and the decrease continues in this order. This is what Newton called the "quadratic proportion" law, which simply states that the power of light is inversely proportional to the square of the distance. Newton supports this law for the theory of universal gravitation, which is still in a hypothetical state. He hypothesized that if the Moon's attraction to the Earth causes the natural satellite to rotate around the Earth, then the movement of the planets around the Sun should be caused by a similar force. But he did not limit himself to hypotheses, but began to make a book of their mathematical expressions and physical laws. It took decades before the calculations arrived at the famous "Law of Universal Gravitation". It is worth noting that this calculus could not have perfected this important physical law without Newton's powerful mathematical method, which was new for his time and is now called differential and integral calculus, and perhaps remained in the form of a hypothesis for him. would have gone. In fairness, it is permissible to recognize the services of Robert Hooke. That is, meticulous Hook, familiar with Newton's scientific conclusions, explained to him that the falling body should deviate not only to the east, but also to the south-east. Practical experience confirmed Hooke's opinion. Hooke also corrected another error of Newton's: Newton thought that the trajectory of a falling object would draw a helical line due to the rotational motion around the earth's core. Hook, on the other hand, says that the spiral line is formed only if air resistance is taken into account, and in space it is elliptical, that is, if this fall is in the direction of the actual movement when we can observe it from outside the earth. said that it is permissible.
Checking Hooke's recommendations, Newton found that objects thrown with sufficient velocity simultaneously form an elliptical trajectory under the influence of the earth's gravity. Perplexed by this reasoning, Newton discovered the famous theorem: a body under the influence of a force similar to the earth's gravity always draws one of some conic sections (ellipse, hyperbola, parabola, and in special cases a circle and a straight line). . In addition, Newton determined that the center of gravitational forces acting on a body in motion, that is, the center of concentration of all gravitational forces, is located at the focus of the considered curve. That is, the center of the Sun is located at the common focus of the ellipses, the curve drawn by the orbits of the planets.
Having achieved such results, Newton realized that Kepler had theoretically recreated one of Kepler's laws, which states that the orbits of the planets draw an ellipse in space, and the center of the sun is at the focus of this ellipse. But this matching of theory and observation alone satisfied Newton. He wanted to be sure whether, according to this theory, it would be possible to calculate the elements of the planets' orbits, that is, whether it would be possible to determine all the details of the movements of the planets. At first he was not lucky.
John Conduitt writes: "In 1666 he went again from Cambridge to Lincolnshire to visit his mother... and as he sat meditating in that garden again, it occurred to him that the force which causes an apple to fall to the ground is not limited to some distance from the ground, but the idea that it will retain its effect even at much greater distances than thought has come. Why should the effect of this force (which forces the apple to fall to the ground) not reach, for example, the Moon? Newton asked himself. If so, it must be the force that must influence the motion of the moon and hold it in its orbit. Based on this idea, he began to calculate the value of such an effect. He did not have the literature necessary for his calculations, which gave a clear idea of the dimensions of the earth. Because of this, Afkor worked on the basis of Norwood's geodetic values, which were widely considered to be 60 miles per degree of latitude on the earth's surface. The calculation results did not agree with the theoretical views and had to be satisfied with the assumption that there is some other cumulative force acting on the Moon in addition to the force of theft...»
The study of the laws of elliptic motion served as a factor in the advancement of Newton's research. But still, Newton constantly assumed that there was some factor or source of error that was overlooked in the theory. Newton's internal doubt remained until the calculations were reconciled with the results of observation. Only by 1682, Newton was able to use the more accurate values of the length of the Earth's meridian, recorded by the French scientist Picard. Knowing the length of the meridian, the scientist calculated the diameter of the Earth and achieved new results in his calculations. The scientist was overjoyed that all his previous scientific views were clearly confirmed. The force that made the apple fall to the ground was the same as the force that controlled the motion of the moon.
This result celebrated for Newton the discovery of a great fundamental physical law as a result of his many years of deep scientific hypotheses and calculations. The scientist's account books turned out to be accurate. Assumptions were confirmed. Finally, he was now firmly convinced that his scientific observations about the structure of the universe were true. The laws of motion of the moon and planets, and even comets, which are considered to be wandering in space, became completely clear to him. It became possible to scientifically analyze and predict the movements of all celestial bodies in the solar system, the Sun itself, and even stars and star systems.
At the end of 1683, Newton presented to the Royal Society his doctrine of the universal laws of motion in the form of a series of theorems on the motion of the planets.
the idea was so ingenious that there were no people who wanted to share the fame and prestige that came with it, who tried to appropriate it, or who were jealous. Because those who understood the essence of this teaching were very few. Undoubtedly, before Newton, several English scientists came close to the solution of this problem. But understanding the difficulty of a question does not mean knowing how to solve it. Let's get acquainted with the conclusions of some of them:
The famous architect Christopher Wren explains the movement of the planets by the process of their pursuit of the Sun (or falling into it) and evaluates it as the result of some initial movement. The astronomer Halley believed that the force in Kepler's laws is inversely proportional to the square of the distance, but he could not prove this. Hooke assured the members of the Royal Society that all the ideas presented in the "Foundations" had been proposed to them a hundred times, and that it was a great mistake that they had not been recognized earlier. Huygens, on the other hand, completely and firmly rejected the idea of mutual attraction of particles and bodies in general, and he stated that only the constituent particles of bodies can attract each other. Leibniz, however, thought that the force that diverted travelers from rectilinear motion and moved them in a circular direction could only be the effect of some ethereal lumpy fluid that filled the universe. Bernoulli and Cassini strongly agreed with this idea.
But slowly all the noise died down. The great discovery has been practically confirmed in all scientific circles. The scientist's services to science were recognized. Newton - As a great genius who revealed the secrets of universal motion, he left an indelible mark in the history of mankind...
