JOHANN KEPLER
Johann Kepler was born in the German state of Stuttgart on December 27, 1571 in a poor Protestant family. At the age of six in 1577 Kepler first saw a comet, the same comet was observed and described by the Danish astronomer Tycho Brahe. In 1589 Kepler graduated from the school at the Maulbronn monastery, and for his outstanding abilities in almost all Sciences, the city authorities awarded him a scholarship to help him further his studies, but Johann was very sickly, ailments followed him all his life.
At the end of the XVI century in many cities of Europe, there was an open confrontation between groups of people who had different ideas about the structure of the Universe. And in 1600, both exiles Kepler and Brahe met in Prague, but it soon became clear that the way Kepler represented astronomy, Tycho Brahe shared only partially. To preserve the already relatively outdated model of the universe, according to which the Central position in the Universe is occupied by the stationary Earth, Brahe proposed a compromise model: all the planets, except the Earth, rotate around the Sun, and the Sun rotates around the stationary Earth (geo-heliocentric system of the world).
The three laws of planetary motion formed by Kepler gave answers to many questions related to the shape of the orbit and the speed of the planets.
Keplers first law (the law of ellipses): Every planets orbit is an ellipse with the Sun at a focus.
Keplers second law (law of squares): Each planet moves in a plane passing through the center of the Sun, and for equal periods of time, the radius vector connecting the Sun and the planet covers equal areas. In simple words, the Sun is not in the center of the ellipse that the planets move along, so the closer the planet is to the sun, the faster it moves in its orbit. For example, the speed of the Earth as it orbits the Sun changes every six months by about 4,000 km/h.
Keplers third law (harmonic law): The Squares of the periods of the planets rotation around the Sun are referred to as cubes of the large semi-axes of the planets orbits. In other words, when a planet approaches the Sun, the radius (half axis) of its orbit decreases, but the speed, and therefore the time of movement (period) increases.
Only in 1609, with great agony, Kepler managed to publish his works, in which the scientist explained not only the new astronomy and physics of the sky, but also for the first time found out what is the cause of ocean tides. Kepler absolutely proved that the Moon is the cause of tides. It was also Kepler who introduced the term inertia into physics as the innate property of bodies to resist an applied external force, forming in a clear form the first law of mechanics: Any body that is not affected by other bodies is at rest or performs a uniform rectilinear motion.
The works of Johannes Kepler on optical phenomena can be considered the beginning of optics as a science. In his works, he outlined geometric and physiological optics, described the General theory of lenses, light refraction, refraction, and the concept of an optical image. Kepler also discovered the role of the human lens for the first time, describing the causes of myopia and farsightedness, and an in-depth study of optical laws led Kepler to the scheme of a telescopic telescope (Kepler telescope).
Craters on the moon and Mars, a supernova, an orbiting Observatory, and a spacecraft were named in memory of the great scientist.
GALILEO GALILEI
Galileo was born in 1564 in Pisa and belonged to a ruined Florentine family. From an early age, the boy was attracted to art; all his life he was interested in music and drawing he mastered them perfectly. In 1581, 17-year-old Galileo, at the insistence of his father, entered the University of Pisa to study medicine, but was passionately interested in geometry, and in 1592, Galileo received a place at the prestigious and rich University of Padua, where he taught astronomy, mechanics and mathematics. After learning about the invention of the telescope in Holland, Galileo decided to build his own telescope. In 1609. he assembled the first telescope and pointed it at the sky. Soon he was able to build a telescope that gives a magnification of 32 times. It is also important to note that the term telescope was introduced into science by Galileo. Using the telescope, which became the main instrument of all astronomers, Galileo Galilei saw the surface of the moon and discovered mountains and craters on the moon, and the milky Way broke up into separate clusters of stars. But even more surprisingly, Galileo was able to see as many as four moons of Jupiter. In Florence, Galileo continued his scientific research, discovering the phases of Venus, spots on the Sun, and then the rotation of the Sun around its axis.
Galileo was a very versatile man, who invented hydraulic scales, studied probability theory, created a prototype microscope with which he studied insects; also worked on the theory of color and magnetism, the resistance of materials, optics and acoustics. He was the first to experimentally measure the density of air. Galileo was a gifted writer and philosopher, and he was certainly the founder of both experimental and theoretical physics, and even Einstein called Galileo the father of modern science. He can be considered one of the founders of mechanism, because it is the analysis of mechanical movement that underlies his work. This scientific approach considers the Universe as a large mechanism, and complex natural processes as combinations of the simplest causes, the main of which is mechanical movement.
As you know, Galileo studied inertia and free fall, and in his last book formulated the laws of fall: The speed increases in proportion to time, and the path increases in proportion to the square of time. This contradicted the famous statements of Aristotle that the speed of falling is greater the greater the weight of the body. However, with the Catholic Church, things did not go so smoothly for Galileo. The fact is that the absolute majority of his works contained a variety of different statements and hypotheses that completely contradicted Aristotle, namely, the works of Aristotle built the medieval worldview. Seeing the obvious refutations of the geocentric system of the world and its fallacy, he decides to fight for the truth with the Catholic Church. His books violated the prohibition on promoting the Pythagorean doctrine, and Galileo was faced with a choice: either he would repent and renounce his errors, or he would suffer the fate of Giordano Bruno. Galileo confirmed that he agreed to recite the required recantation, and then was sentenced to prison. He spent the rest of his life under house arrest and the constant supervision of inquisitors. Galileo Galilei died on January 8, 1642, at the age of 78, in his bed. Pope Urban forbade the burial of Galileo in the family crypt in Florence. The greatest scientist of the middle Ages was buried without honors, and the head of the Catholic Church also did not allow to erect a monument. Officially, the Vatican rehabilitated Galileo Galilei only in 1992.
Among the most famous students of Galileo are Torricelli, who became a physicist and inventor, Castelli, the Creator of hydrometry, and Borelli, the founder of biomechanics. Craters, satellites, asteroids, and a NASA space probe were named in memory of the great scientist of the middle Ages.
Among the most famous students of Galileo are Torricelli, who became a physicist and inventor, Castelli, the Creator of hydrometry, and Borelli, the founder of biomechanics. Craters, satellites, asteroids, and a NASA space probe were named in memory of the great scientist of the middle Ages.
ISAAC NEWTON
On Christmas night, 1642, a weak and quiet baby was born in the village of Woolsthorpe, named Isaac. Relatives did not baptize the baby at first, because they were afraid that the premature baby would not recover. Isaacs mother was a widow, and he grew up without friends, and did not participate in noisy games that required skill and physical strength. Even as a child, he built a kind of water clock that measured time so accurately that soon the whole family began to use it. In 1655, 12-year-old Newton was sent to study at a nearby school in Grantham, where he lived in the house of an Apothecary. From the first lessons, the boy showed outstanding abilities. Isaac preferred all other pursuits to writing poetry, reading books, and constructing various mechanisms. In his youth, Isaac passionately devoted himself to writing poetry. After completing his education at school, Newton was able to continue his education at the University of Cambridge. More than 30 years of Newtons life are associated with this educational institution. The basics of many Sciences were given to Newton without much difficulty, but despite the discoveries of Galileo, natural science and philosophy, Cambridge still taught according to Aristotle. After passing the exams, Isaac received a scholarship, but according to the memoirs of a roommate, Newton completely devoted himself to learning and science, forgetting food and sleep, and probably this is the way of life the young scientist desired for himself. By the age of 23, Isaac Newton was already considered a brilliant mathematician who made a number of discoveries.
In 1664, the plague began in England, and Isaac went to Woolsthorpe, taking with him all the tools and medicines. For three years, according to official data, about 30 thousand people died in London alone. But Isaac was able to find profit in this solitude, and in two plague years Newton made three of his major discoveries: the law of universal gravitation, an explanation of the nature of light, and methods of differential and integral calculus.
We can not help but say, perhaps, about the most famous Apple that fell next to the great scientist, prompting him to study the laws of falling. All his life, Newton was inspired by the great minds of the past Descartes, Galileo and Kepler, and many of his works are based on their work. Conducting optical experiments, Newton built a mixed telescope-reflector, which in addition to its large size gave a 40-fold magnification. Rumors of the new instrument reached London, and after demonstrating his invention to the king, Newton became famous and in January 1672 was elected a fellow of the Royal society. Later, it was with an improved model of the Newtonian telescope that other galaxies, the planet Uranus, and redshifts were discovered. By 1687, Newtons main work was published Mathematical principles of natural philosophy, in which he summed up all his works, forming the law of universal gravitation, which described the gravitational interaction, and the three laws of motion.
The law of universal gravitation States that the force of gravitational attraction F between two immaterial points with masses m1 and m2 separated by a distance r acts along the line connecting them, is proportional to both masses and inversely proportional to the square of the distance.
Three laws of motion:
Newtons first law: Every body continues to be held in its state of rest or uniform and rectilinear motion, until and insofar as it is not forced by applied forces to change this state.
Newtons second law: In an inertial frame of reference, the speed of change in the momentum of a material point is equal to the resultant of all external forces applied to it.
Newtons third law: Action always has an equal and opposite reaction, otherwise the interaction of two bodies on each other are equal and directed in opposite directions.
These laws helped answer the question about the hypothetical acceleration of The earths satellite. Newton knew that the acceleration of the moon in orbit is 0.27 m/s2, and the degree of its orbit is 60 times the radius of the Earth. According to his calculations, the acceleration of a low satellite, that is, all objects on Earth, should exceed the acceleration of the moon by 602 = 3600 times. Using the law of gravity, Newton multiplied 0.27 by 3600 and obtained the famous acceleration of gravity g, equal to 9.8 m/s2.
In 1689 Newton was first elected to Parliament, and again in 1701. Isaac performed his parliamentary duties with the same conscientiousness with which he handled all matters. Written by Newton in 1704, the book Optics, in which he described the seven colors of the rainbow as the main colors of the spectrum, became the basis of this field of physics for the next hundred years. For his contribution to the development of science, the English Queen made Newton a knight. Isaac Newton was a very versatile man in addition to physics, astronomy, and mathematics, he studied alchemy, theology, optical phenomena, and the theory of the ether (a hypothetical all-pervading medium). It was Newton who came up with the idea of making the edges of coins ribbed so that fraudsters could not cut off pieces of metal from them. Despite poor health in childhood, Isaac Newton lived for a full 84 years, dying in 1727, he was not married and left no descendants, but his students and followers made great discoveries in many areas of science.
PIERRE SIMON LAPLACE
For his many achievements in astronomy, physics, and mathematics, Laplace was nicknamed the French Newton. Pierre Simon Laplace was born in 1749 in the family of a farmer in Normandy. In 1765, Laplace entered the University of Caen. The first work of Laplace was associated with the theory of gambling. In the autumn of 1770, having given up his career as a priest and decided to devote himself to science, Laplace came to Paris. In 1773, he was admitted to the Paris Academy of Sciences, and in the same year his fundamental work was published On the principle of universal gravitation and on the age-old inequalities of the planets that depend on it. Laplace was one of the first to openly declare that there should be no God in science, even if you believe in him. Because of the beginning of revolutionary unrest in France, Laplace was forced to flee Paris. In the small town of Melun near Paris, Pierre Simon wrote a book Exposition of the system of the world, in which he collected all the astronomical knowledge of the XVIII century, without using a single formula. But the main thing in this book, Laplace presented his hypothesis of the origin of the Solar system. He suggested that the Solar system was born out of a hot gas nebula that surrounded the young Sun. As it cooled, the nebula began to shrink, and due to the rapid rotation, the centrifugal forces became comparable to gravity, and the nebula flattened, becoming a disk that began to break into rings. The matter in each ring began to thicken, becoming a protoplanet. This theory has existed for more than 100 years, but had a number of significant drawbacks. Also in his book, Pierre Simon came to the conclusion that there are bodies in the Universe with such a huge mass that even light can not leave them. Such bodies are now called black holes. Despite the armed coups in France, Laplace continued to work hard, becoming a member of most of the European academies, and in 1808, he became a member of the French Academy of Sciences. Napoleon, as Emperor, gave Laplace the title of count of the Empire. After the fall of Napoleon and the restoration of the Bourbon dynasty, Laplace received the title of Marquis, became a peer of France, and was awarded the highest order of the Legion of Honor. In 1827, Laplace fell ill and died at the age of 77. His last words were: What we know is so insignificant compared to what we dont know.