XX century can be considered a century of revolution. And not only political, but also scientific. Many believed that from scientists in general there is no use. Sitting, they say, in their cabinets and laboratories for years and all to no avail. What’s the point of spending money on research? But scientists by a series of significant discoveries convinced the whole world that this is not so. At the same time in the XX century, significant discoveries were made extremely often, radically changing our lives. This made it possible to create today a future that the science fiction writers had never even dreamed of. We will tell below about the ten most significant scientific discoveries of the last century, just a decade for each.
The first revolution at the beginning of the century was made by Max Planck. At the end of the XIX century he was invited to the post of professor at the University of Berlin. Planck was so devoted to science that, in his spare time from lectures and work, he continued to deal with issues of energy distribution in the spectrum of an absolutely black body. As a result, a stubborn scientist in 1900 derived a formula that very accurately described the behavior of energy in this case. This had absolutely fantastic consequences. It turned out that the energy is radiated not uniformly, as previously thought, but in batches – quanta. These findings at first confused Planck himself, but he nevertheless reported on the strange results of December 14, 1900 to the German Physical Society. No wonder the scientist simply was not believed. However, based on his conclusions, in 1905 Einstein created the quantum theory of the photoelectric effect. After this, Niels Bohr constructed the first model of the atom, according to which electrons rotate around the nucleus over certain orbits. The consequences of the discovery for Planck’s humanity are so great that it can be considered incredible, ingenious! So, thanks to the scientist later developed nuclear power, electronics, genetic engineering. Astronomy, physics and chemistry received a powerful push. This was due to the fact that it was Planck who clearly marked the boundary where the Newtonian macro world ends with the measurement of matter by kilograms, and the microcosm begins in which it is necessary to take into account the influence of individual atoms on each other. Thanks to the scientist it became known on what energy levels the electrons live, and how they behave there.
The second decade brought an opening that also turned the minds of all scientists. In 1916 Albert Einstein’s work on the general theory of relativity was completed. She received another name – the theory of gravity. According to the discovery, gravity is not a consequence of the interaction of fields and bodies in space, but a consequence of the curvature of the four-dimensional space of time. The discovery immediately explained the essence of many incomprehensible hitherto things. Thus, most of the paradoxical effects that arise at near-light speeds, simply did contradict common sense. However, it was the theory of relativity that predicted their appearance and explained the essence. The most famous of them is the effect of slowing down the time at which the watcher watches are slower than moving around him. It also became known that the length of the moving object along the axis of motion is compressed. Today the theory of relativity is applied not only to objects moving at a constant speed relative to each other, but also to all frames of reference in general. The calculations were so complex that the work took 11 years. The first confirmation of the theory was the description of the curve of the orbit of Mercury, produced with its help. The discovery explained the curvature of rays from stars when passing them alongside other stars, the red shift of galaxies and stars observed in telescopes. A very important confirmation of the theory has become black holes. After all, according to calculations for the compression of a star like the Sun up to 3 meters in diameter, light just can not leave it – this will be the force of attraction. Recently, scientists have found many such stars.
After the discovery, made in 1911 by Rutherford and Bohr, about the structure of the atom by analogy with the solar system, the physicists of the whole world were delighted.Soon on the basis of this model, using the calculations of Planck and Einstein on the nature of light, it was possible to calculate the spectrum of the hydrogen atom. But in the calculation of the next element, helium, difficulties arose-the calculations did not show the same results as the experiments. As a result, by the 1920s Bohr’s theory had faded and began to be questioned. However, the solution was found – the young German physicist Heisenberg managed to remove some assumptions from Bohr’s theory, leaving only the most necessary. He established that it is impossible to simultaneously measure the location of electrons and their velocity. This principle was called “Heisenberg uncertainty”, the electrons appeared to be unstable particles. But even here the oddities with the elementary particles did not end. By that time, physicists had grown accustomed to the idea that light can manifest the properties of both particles and waves. Duality seemed paradoxical. But in 1923 the Frenchman de Broglie suggested that the properties of a wave can be enjoyed by ordinary particles, demonstrating the wave properties of an electron. The experiments of de Broglie were confirmed immediately in several countries. In 1926, Schroedinger described the material waves of de Broglie, and the Englishman Chirac created a general theory, the assumptions of Heisenberg and Schrödinger entered it as special cases. In those years, scientists did not suspect elementary particles at all, but that theory of quantum mechanics perfectly described their movement in the microworld. For the following years, the basis of the theory has not undergone any obvious changes. Today, in any natural sciences, emerging at the atomic level, quantum mechanics is used. These are engineering sciences, medicine, biology, mineralogy and chemistry. The theory made it possible to calculate molecular orbitals, which in turn allowed the creation of transistors, lasers, and superconductivity. It is quantum mechanics that we are obliged to the appearance of computers. Also on the basis of it the physics of a solid was developed. That’s why new materials appear every year, and scientists have learned to clearly see the structure of matter.
Decade of the thirties can be called radioactive without error. Although back in 1920, Rutherford expressed a strange hypothesis at that time. He tried to explain why positively charged protons do not repel. The scientist suggested that in addition to them, there are some neutral particles in the core, equal in mass to protons. By analogy with the already known electrons and protons, Rutherford proposed to call them neutrons. However, the learned world did not take the idea of the physicist seriously. Only 10 years later the Germans Becker and Bote discovered unusual radiation when irradiating boron or beryllium with alpha particles. Unlike the latter, unknown particles emitted from the reactor had much more penetrating power. And the parameters were different for them. Two years later, in 1932, the Curie couple decided to send this radiation to heavier atoms. It turned out that under the influence of these unknown rays, they become radioactive. This effect is called artificial radioactivity. In the same year, James Chadwick managed to confirm these results, as well as to find out that the nuclei from the atoms are knocked out by new uncharged particles with a mass slightly larger than the proton. It was the neutrality of such particles that allowed them to penetrate into the nucleus, destabilizing it. So Chadwick discovered the neutron, confirming the thoughts of Rutherford. This discovery has brought humanity not only good, but also harm. By the end of the decade, physicists were able to prove that nuclei can be shared by neutrons and that even more neutral particles are released. On the one hand, such use of such an effect led to the tragedy of Hiroshima and Nagasaki, the decades of the Cold War with nuclear weapons. And on the other – the emergence of nuclear power and the use of radioisotopes in a variety of scientific fields for widespread use.
With the development of quantum theories, scientists not only could understand what was happening inside the substance, but also try to influence these processes.The case with the neutron is mentioned above, but in 1947 employees of the American company At @ T Bardeen, Bratteyn and Shockley were able to learn how to control the large currents flowing through semiconductors with the help of small currents. For this they will subsequently receive the Nobel Prize. So the transistor appeared in the light, in it two p-n junctions are directed towards each other. By the transition, the current can go only in one direction, with a change in the polarity transition, the current ceases to flow. In the case of two transitions, directed to each other, unique opportunities appeared to work with electricity. The transistor gave a tremendous impetus to the development of all science. From electronics, the lamps left, which sharply reduced the weight and volume of the equipment used. Logical microchips appeared, which gave us in 1971 a microprocessor, and later a modern computer. As a result, to date, there is not one device, car or even a home in which the transistor is not used.
German chemist Ziegler studied the reaction of Grenyar, which helped greatly simplify the synthesis of organic substances. The scientist wondered if it was possible to do the same with other metals. His interest had a practical side, because he worked in the Kaiser Institute for the Study of Coal. A by-product of the coal industry was ethylene, which had to be disposed of somehow. In 1952 Ziegler studied the decomposition of one of the reagents, as a result, low-density polyethylene, HDPE, was obtained. However, it was not possible to fully ethylene polymerize. However, unexpectedly helped by the case – after the reaction from the flask, the polymer unexpectedly dropped out, and the dimer (the combination of two ethylene molecules) is alpha-butene. The reason for this was the fact that the reactor was badly washed from nickel salts. This is what ruined the main reaction, but analysis of the mixture showed that the salts themselves did not change, they only acted as a catalyst for dimerization. This conclusion promised huge profits – earlier for polyethylene it was necessary to use a lot of aluminum organics, apply high pressure and temperature. Now Ziegler began to search for the most suitable catalyst, sorting through the transition metals. In 1953, several were found at once. The most powerful of them were based on titanium chlorides. About his discovery Ziegler told the Italian company Montecatini, where his catalysts were tested on propylene. After all, being a by-product of oil refining costs ten times cheaper than ethylene, giving, moreover, the opportunity to experiment with the structure of the polymer. As a result, the catalyst was slightly upgraded, resulting in a stereoregular polypropylene, in which all the propylene molecules were located identically. This gave the chemist great opportunities in the field of polymerization control. Soon, an artificial rubber was created. Today, organometallic catalysts have made it possible to conduct most of the syntheses cheaper and easier, they are used in virtually all chemical plants in the world. However, the most important is the polymerization of ethylene and propylene. Ziegler himself, despite the enormous industrial application of his work, always considered himself a theoretical scientist. Did not become famous and the student who badly washed the reactor.
April 12, 1961 was a significant milestone in the history of mankind – in space, visited his first representative. It was not the first rocket that flew around the Earth. In 1957, the first artificial satellite was launched. But it was Yuri Gagarin who showed that dreams of the stars could someday become a reality. It turned out that under conditions of weightlessness, not only bacteria, plants and small animals, but also humans, can live. We realized that the space between the planets is surmountable. The man visited the moon, an expedition to Mars is being prepared. The solar system is saturated with space agencies. A person near is exploring Saturn and Jupiter, Mars and the Kuiper belt. Around the same planet, there are already thousands of satellites.Among them are meteorological instruments, and scientific (including powerful orbital telescopes), and commercial communications satellites. This allows us today to call anywhere in the world. The distances between the cities seemed to have decreased, thousands of television channels became available.
The birth of the girl Louise in the Brown family on July 26, 1978 became a scientific sensation. Gynecologist Patrick Stapthaw and embryologist Bob Edwards, who participated in the birth, were extremely proud. The fact is that the girl’s mother, Leslie, suffered from obstruction of the fallopian tubes. She, like millions of other women, could not conceive a child by herself. Attempts lasted a long 9 years. The problem was solved by Stepfo and Edward, who for this purpose produced several scientific discoveries at once. They developed a method for extracting an egg from a woman, without damaging it, creating conditions for its existence in a test tube, then artificial fertilization and returning back. The experiment was a success – specialists and parents were convinced that Louise is an absolutely normal child. In the same way, parents helped to appear in the light and her sister. As a result, by 2007, with the help of the method of in vitro fertilization (IVF), more than two million people have been born. If it were not for the experiences of Stepfo and Edwards, this would be simply impossible. Today, medicine has gone even further – adult women give birth to their granddaughters, if their children are unable to do it themselves, women are fertilized with the seed of already dead men … The technique of IVF is gaining popularity – after all, multiple experiments have confirmed that the children from the test tube are no different from those, who are conceived naturally.
In 1985, the scientists of Robert Curl, Harold Kroto, Richard Smalley and Heath O’Brien studied the spectra of graphite vapors formed under the action of a laser on a solid sample. Unexpectedly for them strange peaks appeared, which corresponded to atomic masses of 720 and 840 units. Scientists soon came to the conclusion that a new variety of carbon – fullerene – was found. The name of the find was born from the designs of Buckminster Fuller, who were very similar to the new molecules. Soon there were carbonaceous varieties of soccer and rugby. Their names are associated with sports, as the structure of the molecules was like the corresponding balls. Now fullerenes, which have unique physical properties, are used in many different devices. But the most important was the fact that these techniques allowed scientists to create carbon nanotubes that are twisted and cross-linked graphite layers. Today, science was able to create a tube with a diameter of 5-6 nanometers and a length of up to 1 centimeter. The fact that they are created from carbon, allows them to exhibit a variety of physical properties – from semiconductor to metal. Based on nanotubes, new materials for fiber-optic lines, displays and LEDs are being developed. With the help of the invention, it became possible to deliver biologically active substances to the desired location of the organism, to create so-called nanopipettes. Developed ultra-sensitive sensors of chemicals that are now used in environmental monitoring, for medical, biotechnological and military purposes. Nanotubes help create transistors, fuel cells, of which nanowires are created. The latest development in this area are artificial muscles. In 2007, studies were published that showed that a bundle of nanotubes could behave similarly to muscle tissue. Although the electrical conductivity of artificial formation is similar to that of natural muscles, nanomyshits do not wear out over time. Such a muscle sustained half a million compressions at 15% of its original state, the shape, mechanical and conductive properties as a result did not change. What does it give? It is possible that someday people with disabilities will get new rugi, legs and organs, which can only be controlled by the power of thought. After all, the thought for the muscles is like an electrical signal to bring it into action.
The 1990s became an era of biotechnology. The first worthy representative of the work of scientists in this direction was the ordinary sheep. Usually it was only outwardly. For the sake of her appearance, the employees of the Roslin Institute, who in England worked hard for several years. The egg, from which then the famous Dolly appeared, was completely gutted, then the nucleus of the adult sheep’s cage was placed in it. The embryo developed back into the womb and began to wait for the result. Nearly 300 candidates won the title of the first clone of a large living creature – all of them died at different stages of the experiment. Although the legendary sheep survived, her fate was unenviable. After all, the ends of DNA, telomeres, serving as biological clocks of the body, have already counted in Dolly’s body for 6 years. After another 6 years of the life of the clone itself, in February 2003, the animal died from old diseases that had fallen on her – arthritis, specific inflammation of the lungs and other ailments. But in itself the appearance of Dolly on the cover of Nature in 1997 produced a real sensation – it became a symbol of human superiority and science over nature itself. The following years after the cloning Dolly noted the emergence of copies of a variety of animals – dogs, pigs, gobies. It was possible even to obtain clones of second generations – clones from clones. So far, however, the problem with telomeres has remained unresolved, and human cloning around the world remains prohibited. But this direction of science remains very interesting and promising.