The universe is not static. This was confirmed by the studies of astronomer Edwin Hubble back in 1929, that is, almost 90 years ago. He was led to this idea by observations of the movement of galaxies. Another discovery of astrophysicists at the end of the twentieth century was the calculation of the expansion of the Universe with acceleration. Last modified: 2025-01-23 12:01
Science
Polyacrylic acid: description of the substance, its physical and chemical properties, chemical and structural formulas. Methods for obtaining a polymer. The use of polyacrylic acid and its s alts in industry, medicine and agriculture. Properties of polyacrylates. Last modified: 2025-06-01 07:06
The world that surrounds us is in constant motion. Nevertheless, there are systems that can be in a relative state of rest and equilibrium. One of them is the lever. In this article, we will consider what it is from the point of view of physics, and also solve a couple of problems on the equilibrium condition of the lever. Last modified: 2025-01-23 12:01
Sergei Alekseevich Lebedev: a brief biography, a description of his activities and achievements in the field of electronic computing technologies. Awards received during his lifetime and posthumously. Personal life and family of a scientist. Memory of S. A. Lebedev. Last modified: 2025-01-23 12:01
What is social science. The concept and essence of social science as a science. The role of social science in human life. Last modified: 2025-01-23 12:01
Since ancient times in Russia, in order to characterize a hero or just a large man, they said: "A slanting sazhen in the shoulders." What is this - a sazhen? Is this an accurate definition of chest width or artistic hyperbole? Let's figure it out. After all, the usual for us meter, centimeter (and at the same time kilogram and liter) as measures were taken relatively recently. Last modified: 2025-01-23 12:01
In installations and devices that create alternating current, reactive energy is used in the mains, which creates a magnetic field of the electric field. Active and reactive energy are different in that the latter is the remainder of the energy that is not used in useful work. Last modified: 2025-01-23 12:01
The above material outlines the main moments of the life of the second cosmonaut in the history of the USSR and all mankind. Last modified: 2025-01-23 12:01
Amplitude modulation was the first way communications engineers learned to transmit speech and music programs over the air. Last modified: 2025-01-23 12:01
Everyone has had memorable events in their lives: joyful and sad, long-awaited and unexpected, memorable and ordinary, public and private. What significance do they have for us? What is their role in our life? The word "event" comes from the Old Slavonic "sbytisya", which appeared in Russian in the 11th century. Its meaning, obviously, is the fulfillment, the realization. Last modified: 2025-01-23 12:01
Class Flagellates: general characteristics, structural features of the body and the presence of organelles that perform certain functions. Classification of this group of living organisms. Nutrition and reproduction. The role of flagellates in nature and human life. Last modified: 2025-01-23 12:01
What is sex-linked inheritance? Why can only men or only women be carriers of some traits? You will find the answers to these questions by reading this article. Last modified: 2025-01-23 12:01
The phenomenon of electronic voice seems to many to be a mysterious message from the other world. But is it really so. Maybe it's all about a sincere desire to believe that life does not end with death? You will find the answer in this article. Last modified: 2025-01-23 12:01
Bacteria started life on our planet. Scientists believe that everything will end with them. There is a joke that when aliens studied the Earth, they could not understand who its real owner is - a man or a bacillus. Last modified: 2025-01-23 12:01
The article fully describes the life, achievements and great discoveries of a man of genius, naturalist Vladimir Ivanovich Vernadsky. Last modified: 2025-01-23 12:01
The article describes the life, work and scientific achievements of the famous philosopher and mathematician Rene Descartes. Last modified: 2025-01-23 12:01
The article describes the basic principles of plant and animal breeding, as well as microorganisms that are necessary for human life. Last modified: 2025-01-23 12:01
Constellation Triangulum is a small constellation located in the northern hemisphere of the sky. Contains a total of 25 stars that can be observed with the naked eye, with a small area of only about 131.8 square degrees. Last modified: 2025-01-23 12:01
What is iron, where does it come from and how is it mined? This useful metal has many applications. The chemical element plays an important role in world industry, and the iron cycle in nature is important in the life of the planet. Last modified: 2025-01-23 12:01
"Whether there is life on Mars or not, science still does not know" - this common aphorism comes from a good old Soviet movie, it seems that it is no longer relevant. Recent studies of the Red Planet have clarified the situation. Last modified: 2025-01-23 12:01
Nucleotides are monomeric units that form more complex compounds - nucleic acids, without which the transfer of genetic information, its storage and reproduction is impossible. Free nucleotides are the main components involved in signaling and energy processes that support the normal functioning of cells and the body as a whole. Last modified: 2025-01-23 12:01
The Eagle constellation is located in the equatorial region. It is one of the 48 constellations documented by Ptolemy, a Greek astronomer, in the 2nd century. The Romans called it the "Flying Vulture". Last modified: 2025-01-23 12:01
Acetylene is in high demand in industry. It finds application in the process of obtaining products of organic synthesis. These are synthetic rubber, plastics, solvents, acetic acid, etc. Last modified: 2025-01-23 12:01
The ideas of this scientist were very bold for their time. The world of Copernicus radically differed from the generally accepted views of his predecessors and contemporaries. Nicholas rejected the geocentric system of the world, which was created by Ptolemy. At the time, this was a bold move, as this model was rarely questioned. She was supported by the very influential Catholic Church at that time. Last modified: 2025-01-23 12:01
Any form of living matter is prone to change, and they can occur both in a positive direction and in a negative one. In the second case, such a process is called regression or degradation, and it is characterized by a gradual deterioration in the state of a certain object or phenomenon. Last modified: 2025-01-23 12:01
What can be said about the main feature of a command economy? How is it expressed? What is its essence?. Last modified: 2025-01-23 12:01
Virulence is a term for the degree of pathogenicity of a microbe. There are several types of pathogens that cause diseases ranging from the common cold to cancer. Virulence factors contribute to pathogenicity, that is, help to cause disease. Last modified: 2025-01-23 12:01
In molecular biology, hybridization is a phenomenon in which single-stranded deoxyribonucleic acid (DNA) or ribonucleic acid (RNA) molecules are annealed to complementary DNA or RNA. One of the most advanced hybridization techniques is FISH. Last modified: 2025-01-23 12:01
What is the pressure of a gas, liquid and solid. Is there pressure in a vacuum. Clear explanations within the framework of the school physics course. Last modified: 2025-01-23 12:01
Surely everyone has seen how in the cinema or the circus people hold a flame on their hand, or even juggle or throw it. And if special effects in a film can be created using computer graphics, then in a circus it looks like a real miracle. In fact, this phenomenon has a completely scientific explanation and is called “cold fire” by chemists. Last modified: 2025-01-23 12:01
Aliphatic amino acids - derivatives of carboxylic acids - are widely distributed in nature. They play an important role in many vital processes. Based on them, some types of medicines are made. Last modified: 2025-01-23 12:01
The constellation Sail is located in the southern hemisphere of our sky. Although part of it can be observed in Russia. Its area is more than 500 square meters. This means that the constellation Sail is the thirty-second largest star cluster in the list. It has 195 stars visible from our planet with the naked eye. Last modified: 2025-01-23 12:01
The nephron is not only the main structural but also the functional unit of the kidney. It is here that the most important stages of urine formation take place. Therefore, information about what the structure of the nephron looks like, as well as what functions it performs, will be very interesting. Last modified: 2025-01-23 12:01
The planet Saturn is one of the gas giants of the solar system. It is the second largest after Jupiter, has a huge mass and a dense layer of rings that surround it. Saturn's atmosphere is a phenomenon that has been the subject of controversy among scientists for many years. But today it has been reliably established that it is gases that form the basis of the entire air body, which does not have a solid surface. Last modified: 2025-01-23 12:01
In 1924, the young French theoretical physicist Louis de Broglie introduced the concept of matter waves into scientific circulation. This bold theoretical assumption extended the property of wave-particle duality (duality) to all manifestations of matter - not only to radiation, but also to any particles of matter. And although modern quantum theory understands the “wave of matter” differently than the author of the hypothesis, this physical phenomenon associated with real particles bears his name. Last modified: 2025-06-01 07:06
Building mechanics is related to lines of influence. Let's reveal their distinctive characteristics, construction features. Last modified: 2025-01-23 12:01
Iron is present in water in the form of divalent and trivalent ions. How to clean drinking and technical liquids from these contaminants? An urgent problem for an ordinary family and a large enterprise. Consider the reasons on which the solubility of iron in water depends, the forms of pollutants, methods for removing ferrocompounds. Last modified: 2025-01-23 12:01
Alpha and beta decays of nuclei are widely known phenomena. In addition to them, there are a number of other reactions that are less common. Each of these processes is worth considering in order to have an idea about atomic physics. Last modified: 2025-01-23 12:01
Let's consider the relationship between unsaturated hydrocarbons of the acetylene series and saturated alkanes using the dehydrogenation reaction as an example. Last modified: 2025-01-23 12:01
What is kinematics? For the first time, secondary school students begin to get acquainted with its definition in physics lessons. Mechanics (kinematics is one of its branches) itself constitutes a large part of this science. Last modified: 2025-01-23 12:01