Keep your eyes on the ceiling
Once, he stood in the Catholic church in Pisa, staring at the ceiling, motionless. What is he doing? It turned out that he followed the pulse of his left hand with his right hand and looked at the light swinging back and forth on the ceiling. He found that although the swing of the lamp is getting weaker and weaker, the distance of each swing is gradually shortened, but the time required for each swing is the same. So Galileo made a pendulum with a suitable length to measure the speed and uniformity of the pulse. From here, he discovered the law of pendulum. This clock is made according to the law he discovered.
If you drop out of school, study hard.
The poverty of family life forced Galileo to leave college early. After dropping out of school, Galileo still studied hard at home. Thanks to his continuous efforts, he has made excellent achievements in mathematics research. At the same time, he also invented the pycnometer and wrote a paper entitled "The Center of Gravity of Solids". At this time, Galileo, 2 1 year-old, has become famous all over the country, and people call him "the contemporary Archimedes". At the age of 25, Pisa University made an exception and hired him as a professor of mathematics.
The world-famous falling body experiment
Before Galileo, Aristotle in ancient Greece thought that the speed of falling objects was different. Its falling speed is proportional to its weight. The heavier the object, the faster it falls. For example, an object weighing 10 kg falls 1 0 times faster than an object weighing1kg.
Since 1700 years ago, people have always regarded this theory that violates the laws of nature as an indisputable truth. Young Galileo boldly questioned Aristotle's theory based on his own empirical reasoning. After careful consideration, he decided to do an experiment by himself. He chose the Leaning Tower of Pisa as the experimental field. On this day, he brought two iron balls with the same size but different weights, one of which weighed 10 Jin and was solid; The other one weighs 1 kg and is hollow. Galileo stood on the leaning tower of Pisa and looked under it. The tower was crowded with people who came to watch, and everyone was talking about it. Someone sarcastically said, "This young man must be crazy! Aristotle's theory cannot be wrong! " The experiment began. Galileo took an iron ball in each hand and shouted, "Look carefully, people below, the iron ball is going to fall." With that, he opened his hands at the same time. People saw two iron balls falling in parallel and falling to the ground almost at the same time. All the people were dumbfounded. Galileo's experiment revealed the secret of falling body movement and overthrew Aristotle's theory. This experiment is of epoch-making significance in the history of physics development.
Made the first telescope.
Copernicus was an outstanding Polish astronomer. After 40 years of astronomical observation, he put forward "Heliocentrism". He thinks that the center of the universe is the sun, not the earth. The earth is an ordinary planet, which revolves around the sun while rotating. Galileo believed in Copernicus' "Heliocentrism" very early. 1608 One day in June, Galileo discovered an empty tube with a convex mirror embedded in one end and a concave mirror embedded in the other end, and made the world's first small astronomical telescope. Experiments show that it can enlarge the original object three times. Galileo was not satisfied, so he further improved and made another one. He took this telescope and ran to the seaside, only to see the vast sea rolling and not seeing a boat. However, when he picked up the telescope and looked into the distance, a ship was coming to the shore from a distance. Practice has proved that it can be enlarged by 8 times. Galileo continued to improve and manufacture, and finally, his telescope could enlarge the original 32 times.
Confirmed Copernicus' Heliocentrism
Every night, Galileo used his telescope to observe the moon. He saw mountains, deep valleys and volcanic cracks on the moon. Later, I began to observe space and explore the mysteries of the universe. He found that the Milky Way is made up of many small stars. He also found that there are black spots in the sun, and the positions of these black spots are constantly changing. So he concluded that the sun itself was spinning. Galileo buried his head in observation and proved with irrefutable facts that the earth revolves around the sun, and the sun is just an ordinary star, thus proving the correctness of Copernicus' theory. 16 10, Galileo published the famous Star Messenger. People admire and say, "Columbus discovered the new continent and Galileo discovered the new universe."
brief introduction
Galileo was a great Italian physicist and astronomer and a pioneer of the scientific revolution. In history, he first integrated mathematics, physics and astronomy on the basis of scientific experiments, expanding, deepening and changing human understanding of material movement and the universe. Galileo devoted his life to proving and spreading Copernicus' Heliocentrism. As a result, he was persecuted by the church in his later years and imprisoned for life. He overthrew the traditional speculative view of nature represented by Aristotle with systematic experiments and observations, and founded a modern science based on experimental facts and with a strict logical system. Therefore, he is called "the father of modern science". His work laid the foundation for the establishment of Newton's theoretical system.
Early activities
Galileo was born in Pisa on February 5th, 564. His father, Fen Cenzio Galileo, is proficient in music theory and acoustics, and has written a book "Music Dialogue". 1574 The whole family moved to Florence. Galileo was influenced by his father since childhood and was very interested in music, poetry, painting and machinery. Like his father, he is not superstitious about authority. /kloc-at the age of 0/7, he studied medicine at the University of Pisa according to his father's orders, but he was tired of medicine. After class, he listened with great interest to the lecture of the famous scholar O. Rich, who is a friend of our family. He taught Euclid geometry and Archimedes statics.
1583, Galileo noticed the swing of a chandelier in Pisa church, and then made a simulation (simple pendulum) experiment with a copper ball suspended by a wire, which confirmed the isochronism of the tiny swing and the influence of the swing length on the period, and thus created a pulse meter for measuring short time intervals. From 65438 to 0585, he dropped out of school because of family poverty and became a tutor, but he still worked hard to teach himself. 1586, he invented the buoyancy balance and wrote the paper "Small Balance".
1587, he took a paper on the calculation of solid center of gravity to the University of Rome and called on Professor C. Clavius, a famous mathematician and historian, who was greatly praised and encouraged. Clavius brought back his lectures on logic and natural philosophy from P Vara, a professor at the University of Rome, which was of great help to his future work.
From 65438 to 0588, he gave an academic lecture on the graphic conception of purgatory in A. Dante's Divine Comedy, and his literary and mathematical talents were greatly praised. The following year, he published several papers on the calculation of solid center of gravity, including some new statics theorems. Because of these achievements, the University of Pisa hired him to teach geometry and astronomy. The next year he discovered the cycloid.
At that time, the textbooks of Pisa University were all written by Aristotelian scholars, and the books were full of theological and metaphysical dogmas. Galileo often expressed sharp objections and was discriminated and rejected by the school. 159 1 year, his father died of illness and the family burden increased, so he decided to leave Pisa.
Padua period
1592 Galileo transferred to the University of Padua to teach. Padua belongs to the principality of Venice, far from Rome, not directly controlled by the Vatican, and his academic thoughts are relatively free. In this good atmosphere, he often participates in various academic and cultural activities inside and outside the school, arguing with colleagues with various ideas and opinions. At this time, while absorbing the research results of mathematics and mechanics of N.F. tartaglia, G.B. Benedetti, F. Comentino and others, he often inspected factories, workshops, mines and various Zhong Junmin projects, made extensive contacts with technicians from all walks of life, helped them solve technical problems, and learned production technical knowledge and various new experiences, which was deeply inspired.
During this period, he deeply and systematically studied the falling body, projectile motion, statics, hydraulics and some civil and military buildings. Discovered the principle of inertia, invented the thermometer and telescope.
1597, he received a book "The Mysterious Universe" by J Kepler, and began to believe in Heliocentrism, acknowledging that the earth has two movements: revolution and rotation. But at this time, he was deeply impressed by Plato's most natural and perfect circular motion thought, and was not interested in Kepler's theory of planetary elliptical orbit.
1604 A supernova appeared in the sky, and the light lasted for 18 months. He took the opportunity to make several popular science speeches in Venice to promote Copernicus' theory. Because of the wonderful speech, the audience gradually increased and finally reached more than 1000 people.
1609 In July, it was rumored that a Dutch glasses worker invented a telescope for people to enjoy. He didn't see the real thing, so he thought of making a telescope with organ tube and convex-concave lens in the future. The magnification was 3, and then it was raised to 9. He invited Senator Venice to the top floor of the tower and looked at the distant scenery through a telescope, which surprised all the audience. The Senate then decided that he was a tenured professor at the University of Padua. At the beginning of 16 10, he increased the magnification of the telescope to 33 times to observe the moon, the sun and the stars, and found many new discoveries, such as the uneven surface of the moon, the light emitted by the moon and other planets is the reflection of the sun, Mercury has four satellites, the Milky Way was originally a confluence of countless luminous bodies, Saturn has a changeable ellipse and so on, which opened up a new world of astronomy. In March of that year, he published the book Star Messenger, which shocked all of Europe. Later, it was discovered that Venus changed in profit and loss and size, which was a strong support for Heliocentrism.
Galileo later looked back on his 18 years in Padua and thought it was the most productive and spiritual period in his life. In fact, this is also the greatest academic achievement in his life.
Tuscan period
Galileo's fruitful achievements in physics and astronomy in the past 20 years have aroused his greater academic ambition. In order to get enough time to devote himself to scientific research, in the spring of 16 10, he resigned from the university and accepted the appointment of the Grand Duke of Tuscany as the chief mathematician and philosopher of the court and the honorary position of the chief professor of mathematics at the University of Pisa.
In order to protect science from church interference, Galileo went to Rome many times. 16 1 1 year, in order to win the recognition of his discoveries in astronomy from religious, political and academic circles, he went to Rome for the second time. In Rome, he was warmly received by elites including Pope Paul V and some senior bishops, and was accepted as an academician by the Lindsay Institute. At that time, the Jesuit priest acknowledged his observation, but disagreed with his explanation. In May this year, at the meeting of the University of Rome, several senior priests publicly announced Galileo's astronomical achievements.
In the same year, he observed sunspots and their movements, compared the movement law of sunspots with the projection principle of circular motion, and proved that sunspots are on the surface of the sun; He also found that the sun rotates. 16 13 published three communication articles about sunspots. In addition, in 16 12, the book "floating body dialogue in water" was published.
16 15 A perfidious cleric group and many people in the church who were hostile to Galileo jointly attacked Galileo's argument of defending Copernicus and accused him of violating Christianity. After learning the news, he went to Rome for the third time in the winter of, trying to save his reputation and imploring the Vatican not to be punished for keeping Copernicus' views, nor to publicly suppress his propaganda of Copernicus' theory. The Vatican acquiesced in the former request, but rejected the latter. In 16 16, Pope Paul V issued the famous "16 16 ban", forbidding him to reserve, teach or defend Heliocentrism orally or in writing.
1624, he went to Rome for the fourth time, hoping that his old friend, the new Pope urban VIII, would sympathize with and understand his wishes in order to maintain the vitality of emerging science. He had six audiences, trying to explain that Heliocentrism could be in harmony with Christian teachings, saying that "the Bible teaches people how to enter the kingdom of heaven, not how celestial bodies work"; And tried to convince some archbishops, but to no avail. Urbon VIII insists on "16 16 ban" unchanged; He is only allowed to write a book introducing Heliocentrism and geocentric theory at the same time, but his attitude towards these two theories must not be biased, and both should be written as mathematical hypotheses. In this year's efforts, he developed a microscope, "which can enlarge flies into hens."
In the following six years, he wrote a book, Dialogue between Ptolemy and Copernicus (book shadow (see the title page of Galileo's masterpiece Dialogue between Two World Systems (1632)). Chinese translation, Shanghai foreign natural science philosophy works compilation group translation, Shanghai People's Publishing House, 1974). 1630, he went to Rome for the fifth time and obtained the "publishing license" of this book. The book was finally published in 1632. This book is neutral on the surface, but actually defends the Copernican system, and in many places implicitly ridicules the Pope and the Bishop, which goes far beyond the scope of discussing only mathematical assumptions. The book has a humorous style and is listed as a literary masterpiece in the history of Italian literature.
Persecution of the Vatican and the elderly
Half a year after the publication of Dialogue, the Holy See ordered it to stop selling, arguing that the author had blatantly violated the "16 16 ban" and the problem was serious and needed to be examined urgently. It turns out that before Pope urban VIII, Galileo was provoked to say that in the Dialogue, he made some absurd and wrong remarks with the Simpleqiu and conservative mouth, which made him furious. The group that once supported him as pope strongly advocated severely punishing Galileo, while the Holy Roman Empire and the Kingdom of Spain believed that conniving Galileo would have a great impact on heresy in various countries and put forward a joint warning. Under these internal and external pressures and provocations, the Pope ignored his old friends and issued an order this autumn to have Galileo tried by the Roman Inquisition.
Galileo, who was nearly seventy years old and sickly, was forced to go to Rome in the cold winter and was interrogated three times under the threat of torture. There is no defense at all. After several tortures, on June 22nd, 1633, 10 cardinals jointly pronounced the sentence, mainly for violating the "16 16 prohibition" and biblical teachings. Galileo was forced to kneel on the cold slate and sign the "repentance book" written by the Vatican. The presiding judge announced that Galileo was sentenced to life imprisonment; The dialogue must be burned and it is forbidden to publish or reprint his other works. This judgment immediately informed the whole Catholic world that all cities with universities must gather to read it, so as to set an example for others.
Galileo is both a diligent scientist and a devout Catholic, convinced that the task of scientists is to explore the laws of nature, while the function of the church is to manage people's souls and should not infringe upon each other. Therefore, he didn't want to escape before his trial, and he didn't openly resist when he was tried, but he always obeyed the Vatican's disposal. He believes that it is extremely unwise for the Vatican to exercise its power outside the scope of theology, and it can only be privately dissatisfied. Obviously, G Bruno was burned to death at the stake, and T campanella was put on death row for a long time. What happened to these two outstanding Italian philosophers cast a terrible shadow on his spirit.
The inquisition's decision was later changed to house arrest, and his student and old friend Archbishop A. Picolomini was appointed to take care of him in a private house in Siena. The regulations prohibit visitors and hand in writing materials every day. Under the careful care and encouragement of Piclomini, Galileo was resurrected, and he accepted Piclomini's suggestion and continued to study uncontroversial physical problems. So he still wrote his most mature scientific thoughts and achievements into Dialogues on Two New Sciences and Dialogues on Mathematical Proof with three dialogue characters in Dialogues and simple writing style. Two new sciences refer to mechanics and dynamics of materials. This manuscript was completed on 1636. Because the church banned the publication of any of his works, he had to entrust a Venetian friend to smuggle them out of the country and publish them in Leiden, the Netherlands on 1638.
Galileo had just stayed in Piccolomini's house for five months when someone wrote an anonymous letter accusing Piccolomini of being too kind to Galileo. The Vatican ordered Galileo to move to his former residence in Chetri near Florence in June 5438+February of that year, and the ban remained. She took good care of her father, but died before him four months later.
Galileo repeatedly asked to go out for medical treatment, but was not allowed. 1637 is blind. It was not until the next year that he was allowed to live in his son's house. During this period, in addition to the Grand Duke of Tuscany, there were also J Milton, a famous British poet and political commentator, and P Gasanti, a French scientist and philosopher. His student and old friend B. Castay also discussed with him the calculation of ground longitude by using wooden satellites. At this time, the Vatican's restrictions and surveillance on him have been obviously relaxed.
1in the summer of 639, Galileo was allowed to accept the smart and studious 18-year-old youth V. viviani as his last student, and he could take care of him. The young man made him very satisfied. 164 1 10 in June, Casta introduced his student and former secretary e torricelli to accompany him. They discussed with the blind old scientist how to design a mechanical clock by using the isochronism of pendulum, and also discussed the collision theory, the libration of the moon, the height of water column in the mine under atmospheric pressure and other issues, so he was still engaged in scientific research until his death.
Galileo died on1642 65438+1October 8, and the funeral was sloppy. It was not until the next century that his bones were moved to the cathedral in his hometown.
International Year of Astronomy
In 2009. To commemorate the 400th anniversary of Galileo's invention of the refracting telescope.
The United Nations designated 2009 as international year of astronomy.