From the day Archimedes stopped washing in the bathroom shouting "Orca, Orca", science has always surprised everyone with some shocking and interesting news. has done. This news has maintained its capacity even after the great accumulation of knowledge over the past years, and it has also kept its share in surprising the people. In the meantime, some of these surprises happened suddenly; In other cases, revolutionary change took time. Given this situation, Science news Magazine has explored the past 100 years and presents you with a collection of endless wonders of science in this article.
- 10. Violation of parity shows the difference between left and right
- 9. Strange compounds from noble gases
- 8. Plate tectonics
- 7. DNA is made of genes!
- 6. Discover dark energy
- 5. Dark matter
- 4. Atomic bomb and nuclear fission
- 3. Expanding universe
- 2. Antimatter
- 1. Uncertainty principle
10. The violation of parity shows the difference between left and right
In the twentieth century, physicists have come to the conclusion that mathematical symmetries play a very important role in the laws of nature. The existence of symmetry in natural phenomena means that the equations describing the kinds of changes in the physical world must be constant. In other words, seeing the world in the mirror (change from right to left) should not affect the accuracy of those equations and should be equivalent to the world outside the mirror. Hermann Weyl, the great mathematician who died in 1955, acknowledged that all the laws of nature are immutable (in more scientific terms invalid) when exchanged! In fact, there is no preference between left and right.Nature should not distinguish between in-mirror and out-of-mirror images, but the beta decay test showed otherwise!
But it is interesting to note that in 1956, physicists Tsung-Dao Lee and Chen Ning Yang published theoretical papers that were contrary to what was thought. In this paper, the two physicists and their team claimed that nature really distinguishes between left and right (technically, parity (the same mirror image) is violated!). The scientists demonstrated parity violation in an experiment involving the decay of radioactive beta decay of atoms of cobalt atoms and the decay of unstable particles called muons. Left-right, in the direction in which the beta particles are emitted, was shown to be a major surprise in this area. Four decades after the discovery, one of the experimenters, Leon Lederman, acknowledged that the experiment represented new laws in the atomic world and was a breakthrough in theoretical physics.
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9. Strange compounds from noble gases
In the 1890s, chemists introduced a whole new family of elements Periodically added Dmitry Mendeleev; Elements that are called noble or inert gases. These noble gases, which include helium (an element that was detected on the sun decades ago but was not detected on Earth until 1895!), Neon, argon, xenon, krypton and radon, were among the items that were ignored. Other elements did not combine.
In general, these noble elements normally exist in the gaseous state, and the arrangement of electrons around their atoms prevents any possibility of chemical composition. However, in 1962, the Science news Letter announced that an impossible combination of noble gases had been created. have!
This article states that a compound called xenon tetrafluoride has been developed at Argonne National Laboratory in Illinois. It should be noted, however, that in 1962, the chemist Neil Bartlett claimed to have created a compound of the element xenon called xenon-platinum hexafluoride. In that case, the chemists were forced to revise the textbooks, stressing that you had to give up what you already believed.
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8. Plate tectonics
In the 1960s, many geologists realized that textbooks needed to be fundamentally revised and previous information discarded! However, Alfred Wegener was not so surprised! Wegner died in 1930, turning from an astronomer to a meteorologist who also worked in paleontology and geophysics. In the year 1915 He notes in a book that the continents of the earth once existed in the form of a dry (single continent) mass called the Pangaea. It then split apart over millions of years and became something like a map of the world today.
Wegner believed that the map of the world was not a permanent picture of the features of the earth, but a shot of a feature film. But at the time, few scientists believed in Wegener, and geophysicists believed that such a large motion for a mass of this magnitude was not physically justifiable!For the first time, scientists are convinced that the continents have separated over time!
However, Wegner's idea of continental drift did not go unnoticed until the 1960s. Then, when magnetic patterns were detected on the seabed, scientists realized that the oceans had expanded over time and separated the continents. Science news Letter reported in 1963 that new evidence had exposed the controversial argument that continents were once interconnected and supported the theory of continental separation.
Further research in the next few years Showed that continental drift is a sign of complex mechanisms within the earth known as plate tectonics or plate tectonics. The plate tectonics explains not only the location of the continents, but also how the mountain ranges formed and why a series of earthquakes formed in specific areas with seismic activity.
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7. DNA is made of genes!
One of the most remarkable discoveries of the last century (1953) was the discovery of the double helix structure of DNA by James Watson and Francis Crick, using the X-ray image produced by Rosalind Franklin. But a bigger surprise happened a few years before that; When Oswald Avery and colleagues at Rockefeller University showed that DNA is a substance made of genes.In the not-so-distant past, the prevailing view was that genes must be made of a protein. But in 1944, Avery et al. Showed that genes make DNA strands. It is interesting to note that although the existence of genes was proven in the early years of the twentieth century, no one had accurate evidence of their physical structure. In the 1940s, the prevailing view in genetics was that genes must be made of a protein and that the structure of DNA could only be seen as an organic acid of a vague nature, but in 1944, Avery et al. Showed that part of DNA The one that has the instructions or code to make a specific protein is called a gene, and the gene itself is not made of protein.
James Watson (left) and Francis Crick discovered the dual, helical structure of DNA with an X-ray image taken by Rosalind Franklin.
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6. The discovery of dark energy
In the 1990s, the Big Bang theory of the expansion of the universe was questioned and many questions remained; The most important question was the fate of the universe.
At the time, most physicists believed that gravitational pull across the globe was slowing the expansion of the universe. Therefore, with such a process, all the matter of the world will gradually undergo a great contraction, and during a great collapse, the world will collapse! Others thought that the world would expand forever; But as the rate of expansion slowed, so did the story. , Shockingly different!Studies and measurements of the light of distant supernovae have shown that the repulsive force of dark energy can increase the expansion of the universe! New reports from these astronomers and further research have shown that the expansion of the universe is not only not slowing down, but is also increasing at a steady pace. In fact, the presence of repulsive force from dark energy (in the absence of solid knowledge of its true nature) determines this. According to Science News, calculations show that without considering the repulsive force of dark energy, the universe would expand 10 to 15 percent slower than we see today!
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5. Dark matter
In the 1930s, physicist astronomer Fritz Zwicky discovered that the speed of galaxies moving in a cluster called a coma cluster was based on mass expectations. It does not satisfy the gravitational effects of visible objects. Zwicki guessed that the matter in this galaxy cluster was more than just visible matter, so he called this amount of invisible matter dark matter.Invisible halos surround the galaxies, causing the outer edge stars to rotate faster than near-center stars!
Meanwhile, other astronomers, including Horace Babacock, noticed similar differences; This means that the stars around the outer edges of the galaxy (far from the center!) Can rotate much faster than the galaxy allows. In simpler terms, stars are like people in a carousel, spinning too fast (determined by the mass of the galaxy), but not being thrown out! In this regard, scientists believe that such a thing is justified despite the dark matter.
In the 1970s and beyond, Vera Rubin and her colleagues confirmed the speed of outer stars more than the stars in the center of the galaxy. Also, as Science news reported in 1994, such behavior is due to the invisible and enormous halo that pervades galaxies!
Vera Rubin and colleagues have confirmed that outer stars move faster than expected in many galaxies, which is a sure sign of dark matter./p>
Sure, it's amazing to realize that most of the matter in the universe is invisible, but it's even more surprising when you realize that matter is so different from what we see on Earth! Ordinary matter is made up mostly of protons and neutrons, but the true identity of dark matter remains a mystery to this day. In this regard, although physicists have examined various probabilities for dark matter, none have been able to ascertain its reality with certainty.
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4. Atomic bomb and nuclear fission
Since the discovery of radioactivity in some elements, physicists have always speculated about the energy hidden in each piece of matter. After Einstein published his famous equation (E=mc2), it became quite clear to many scientists that there was a lot of energy inside the atom. But at the same time, most experts doubted that there was any practical way to release such energy for useful purposes or weapons of war. In the name of barium, it will be split and nuclear energy will be released! It wasn't until late 1938 that chemists Otto Hahn and Fritz Strassmann realized that if uranium nuclei were bombarded with neutrons, a much lighter element called barium would be produced. In the same vein, Liz Meitner (who had worked with Hahn before fleeing Nazi Germany!) And her nephew, Otto Frisch, discovered that the uranium nucleus had split during such an experiment! In other words, nuclear energy was released! Naturally, after this discovery, the process of nuclear fission became the start of a massive war project to build a powerful and unimaginable bomb that was soon to shock the world with its potential for destruction!
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3. Expanding universe
From ancient times, philosophers and physicists have pondered profound questions about the nature of the universe; For example, is the world finite or infinite? Does it have a beginning or is it eternal? But despite all these and similar questions, it might be interesting for you to know that almost everyone in the past believed that the world as a whole has never changed, but only exists!
In 1929, Edwin Hubble (Hubble at the Wilson Observatory!) Showed that distant galaxies were faster than galaxies. They are getting closer and closer to us, which could be a sign of the expansion of the universe. The world may be expanding or contracting! In fact, it was for the first time that Einstein himself realized this possibility, but he changed his equations in such a way as to predict a world without change, because he saw no evidence to the contrary!
An analysis of data on the color of light emitted from nebulae by Edwin Hubble in 1929 showed that the farther away galaxies are, the farther away they are from us. That means the world is really expanding. According to these reports, Science news Letter reported in 1931 that distant galaxies were moving away from us at an astonishing rate; So our world is constantly expanding and expanding.
- Worm Making Guide; An impossible mission
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In 1930, a bold proposal by a young British physicist named Paul Dirac brought new news to the scientific community. In fact, he claimed that matter (whatever physical objects are made of!) Is nothing more than a bunch of holes in the vacuum of space. Dirac suggested that space It is not empty, but full of electrons that have negative energy. From Dirac's point of view, electrons with negative energy cannot be detected. But if an electron is given enough energy, it is released from the sea of negative energy, creating a hole like an empty bubble in the ocean of negative energy. Simply put, the absence of an electron creates a hole with a positive electric charge.An electron is a particle that has a mass quite similar to a normal electron, but its charge is not negative, but positive! Dirac hypothesized that such positively charged bubbles are similar to protons in an ocean of negative energy. But he soon realized that he was wrong, and that positively charged holes could not be similar to protons, but must have much lighter particles with a mass equal to a normal electron. So Dirac came up with a completely new idea, an idea known as the anti-electron.
Dirac claimed that if an ordinary electron collided with its antiparticle, two particles would be destroyed and energy would be released. It is interesting to note that Dirac's anti-electron was discovered by Carl Anderson in cosmic rays soon after his theory!
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The Uncertainty Principle
In 1927, Werner Heisenberg introduced his uncertainty principle to the world and the scientific community, the idea that underpinned the emerging mathematics to describe the universe called quantum mechanics. Heisenberg's uncertainty principle implies the shocking fact that the unbroken chain of cause and effect (originating in Newtonian physics!) Is just an illusion in the quantum world. The uncertainty principle states that a particle can have an exact location or exact momentum, but it is not possible to have the exact value of both of these parameters! It is interesting to know that the principle of uncertainty is one of the principles that has always been associated with different interpretations by philosophers and still continues!
Source: Science News