There is probably not a single person on the entire planet who has not thought about the incomprehensible flickering points in the sky that are visible at night. Why does the moon go around the earth? All this and even more is studied by astronomy. What are planets, stars, comets, when will there be an eclipse and why tides occur in the ocean - science answers these and many other questions. Let's look at its formation and significance for humanity.
Definition and structure of science
Astronomy is the science of the structure and origin of various cosmic bodies, celestial mechanics and the development of the universe. Its name comes from two ancient Greek words, the first of which means "star", and the second - "establishment, custom."
Next, we will talk about the whole path of formation of this discipline. At the current stage of development, it includes several narrower areas.
Astrophysics studies the composition and properties of celestial bodies. Its subsection is stellar astronomy.
Celestial mechanics answers questions about the motion and interaction of space objects.
Cosmogony deals with the origin and evolution of the universe.
Thus, today, ordinary earth sciences with the help of modern technology can spread the field of research far beyond the borders of our planet.
Subject and Tasks
In space, it turns out, there are a lot of the most diverse bodies and objects. All of them are studied and constitute, in fact, the subject of astronomy. Galaxies and stars, planets and meteors, comets and antimatter - all this is only a hundredth of the questions that this discipline poses.
Recently, a tremendous opportunity for practical space exploration has appeared . Since that time, astronautics (or astronautics) proudly became shoulder to shoulder with academic researchers.
Humanity has long dreamed about this. The first known story is Somnium, written in the first quarter of the seventeenth century. And only in the twentieth century, people were able to look at our planet from the side and visit the Earth’s satellite - the Moon.
Astronomy topics are not limited to these issues. Next we will talk in more detail.
What methods are used to solve problems? The first and oldest of them is observation. The following features have only recently appeared. This is spectral analysis, photography, the launch of space stations and artificial satellites.
Questions concerning the origin and evolution of the universe, individual objects, so far can not be adequately studied. Firstly, there is not enough accumulated material, and secondly, many bodies are too far away for accurate study.
Types of observations
At first, humanity could only boast of ordinary visual observation of the firmament. But even such a primitive method gave simply amazing results, which we will talk about a little later.
Astronomy and space today are connected as never before. Objects are studied using the latest technology, which allows many branches of this discipline to develop. Let's get to know them.
Optical method. The oldest version of observation with the naked eye, with the participation of binoculars, telescopes, telescopes. This also includes recently invented photography.
The next section deals with the registration of infrared radiation in space. With its help, invisible objects (for example, hidden behind gas clouds) or the composition of celestial bodies are recorded.
The importance of astronomy cannot be overestimated, because it answers one of the eternal questions: where did we come from.
The following techniques explore the universe for gamma radiation, x-ray waves, ultraviolet radiation.
There are also techniques not related to electromagnetic radiation. In particular, one of them is based on the theory of the neutrino nucleus. The gravitational wave industry is exploring space to disseminate these two actions.
Thus, the types of observations known at the present time have greatly expanded the capabilities of mankind in space exploration.
Let's look at the process of becoming this science.
The origin and first stages of the development of science
In antiquity, during the primitive communal system, people were just beginning to get acquainted with the world and define phenomena. They tried to realize the change of day and night, the seasons of the year, the behavior of obscure things, such as thunder, lightning, comets. What is the Sun and the Moon - also so far remained a mystery, so they were considered deities.
However, despite this, already in the heyday of the Sumerian kingdom, priests in ziggurats made rather complicated calculations. They divided the visible luminaries into constellations, singled out the “zodiacal belt” known today, and developed a lunar calendar of thirteen months. They also opened the Meton cycle, although the Chinese did it a little earlier.
The Egyptians continued and deepened the study of celestial bodies. They generally have an amazing situation. The Nile River flows at the beginning of summer, just at that time the star Sirius begins to appear on the horizon , which hid in the winter months in the sky of the other hemisphere.
In Egypt, for the first time, they began to divide the day by 24 hours. But the week at the beginning they had ten days, that is, the month consisted of three decades.
However, the most developed ancient astronomy was in China. Here they managed to calculate the length of the year almost exactly, could predict solar and lunar eclipses, kept records of comets, sunspots and other unusual phenomena. At the end of the second millennium BC, the first observatories appeared.
Period of antiquity
The history of astronomy, in our understanding, is impossible without Greek constellations and terms in celestial mechanics. Although at first the Hellenes made very bad mistakes, but over time they were able to make fairly accurate observations. The mistake, for example, was that they saw Venus appearing in the morning and evening as two different objects.
The first who paid special attention to this field of knowledge were the Pythagoreans. They knew that the Earth has the shape of a ball, and day and night are replaced, because it rotates around its axis.
Aristotle was able to calculate the circumference of our planet, however, he was mistaken in a big way by half, but such accuracy for that time was high. Hipparchus was able to calculate the length of the year, introduced such geographical concepts as latitude and longitude. Compiled a table of solar and lunar eclipses. From them it was possible to predict these phenomena with an accuracy of two hours. Learn from our meteorologists from him!
The last luminary of the ancient world was Claudius Ptolemy. The history of astronomy has kept the name of this scientist forever. A brilliant mistake that determined the development of mankind for a long time. He proved the hypothesis that the Earth is in the center of the universe, and all celestial bodies revolve around it. Thanks to warlike Christianity, which replaced the Roman world, many sciences were abandoned, such as astronomy too. What is the Milky Way and what is the circumference of the Earth, no one was interested, they argued more about how many angels would crawl into the eye of a needle. Therefore, the geocentric scheme of the world for many centuries has become the measure of truth.
Astronomy of the Indians
The Incas viewed the firmament a little differently than other nations. If we turn to the term, then astronomy is the science of the motion and properties of celestial bodies. The Indians of this tribe primarily singled out and especially revered the "Great Heavenly River" - the Milky Way. On Earth, its continuation was Vilkanota - the main river near the city of Cuzco - the capital of the Inca empire. It was believed that the sun, setting in the west, sank to the bottom of this river and along it passed to the eastern part of the sky.
It is reliably known that the Incas distinguished the following planets - the Moon, Jupiter, Saturn and Venus, and without telescopes made observations that only Galileo could repeat using optics.
Their observatory had twelve pillars, which were located on a hill near the capital. With their help, the position of the Sun in the sky was determined and the change of seasons, months was recorded.
Maya, unlike the Incas, developed knowledge very deeply. The bulk of what astronomy is studying today was known to them. They made a very accurate calculation of the duration of the year, divided the month into two weeks for thirteen days. The beginning of the chronology was considered to be 3113 BC.
Thus, we see that in the ancient world and among the tribes of "barbarians", which they were considered "civilized" Europeans, the study of astronomy was at a very high level. Let's see what they could boast in Europe after the fall of the ancient states.
Middle Ages
Thanks to the diligence of the Inquisition in the late Middle Ages and the weak development of the tribes at the early stage of this period, many sciences stepped back. If in the era of antiquity people knew that astronomy was studying, and many were interested in such information, then in the Middle Ages theology became more developed. For talking that the Earth is round, and the Sun is in the center, it was possible to burn at the stake. Such words were considered sacrilege, and people were called heretics.
Revival, oddly enough, came from the east through the Pyrenees. Arabs brought to Catalonia the knowledge preserved by their ancestors since the time of Alexander the Great.
In the fifteenth century, Cardinal Kuzansky expressed the view that the universe is infinite, and Ptolemy is mistaken. Such sayings were blasphemous, but they were very ahead of time. Therefore, they were considered nonsense.
But the revolution was made by Copernicus, who, before his death, decided to publish a study of his whole life. He proved that the Sun is in the center, and the Earth and other planets revolve around it.
Planets
These are celestial bodies that rotate in orbit in space. They got their name from the ancient Greek word "wanderer". Why is that? Because to ancient people they seemed to be traveling stars. The rest are in ordinary places, and they move every day.
What is their difference from other objects in the universe? Firstly, the planets are quite small. The size allows them to clear their path of planetesimals and other debris, but it is not enough to start a thermonuclear reaction, like a star.
Secondly, due to their mass, they acquire a rounded shape, and as a result of certain processes form a dense surface. Thirdly, planets usually rotate in a certain system around a star or its remains.
Ancient people considered these celestial bodies to be “messengers” of the gods or demigods, of a lower rank than, for example, the Moon or the Sun.
Next was the era of the "Ptolemaic picture of the world." In these centuries, it was believed that all the planets and other objects revolve around the Earth, and it, in turn, is located in the center of the universe.
And only Galileo Galilei for the first time using observations in the first telescopes was able to conclude that in our system all bodies go in orbits around the Sun. For which he suffered from the Inquisition, which silenced him. But the case was continued.
By definition, recognized today by the majority, only bodies with sufficient mass that revolve around a star are considered a planet. The rest is satellites, asteroids and more. From the point of view of science, there are no loners in these ranks.
So, the time during which the planet makes a full circle in its orbit around the star is called the planetary year. The closest place on its path to the star is the periaster, and the farthest is the apoaster.
The second thing that is important to know about planets is that they have an inclined axis relative to the orbit. Due to this, during the rotation of the hemisphere receive a different amount of light and radiation from the stars. So there is a change of seasons, time of day, climate zones have also formed on Earth.
It is important that the planets, in addition to their path around the star (for a year), still rotate around their axis. In this case, the full circle is called "day."
And the last feature of such a celestial body is its pure orbit. For normal functioning, the planet must, on the way, colliding with various smaller objects, destroy all "competitors" and travel in splendid isolation.
There are different planets in our solar system. Astronomy has a total of eight. The first four belong to the “earth group” - Mercury, Venus, Earth, Mars. The rest are divided into gas (Jupiter, Saturn) and ice (Uranus, Neptune) giants.
Stars
We see them every night in the sky. A black field dotted with shiny dots. They form groups called constellations. And yet it is not in vain that a whole science is called in their honor - astronomy. What is a star?
Scientists say that with the naked eye at a fairly good level of vision, a person can see three thousand celestial objects in each of the hemispheres.
They have long beckoned humanity with their flickering and "unearthly" meaning of existence. Let's take a closer look.
So, a star is a massive lump of gas, a kind of cloud with a fairly high density. Inside it, thermonuclear reactions occur or have occurred before. The mass of such objects allows them to form systems around themselves.
When studying these cosmic bodies, scientists have identified several classification methods. You have probably heard about the “red dwarfs”, “white giants” and other “inhabitants” of the universe. So, today one of the most universal classifications is the Morgan-Keenan typology.
It implies the division of stars in magnitude and spectrum of radiation. In descending order, the groups bear names in the form of letters of the Latin alphabet: O, B, A, F, G, K, M. So that you sort it out a little and find a reference point, the Sun, according to this classification, falls into group “G”.
Where do such giants come from? They are formed from the most common gases in the universe - hydrogen and helium, and, due to gravitational compression, acquire their final shape and weight.
Our star is the Sun, and the closest to us is the proxima Centaurus. It is located in the Alpha Centauri system and is located at a distance of 270 thousand distances from us from the Earth to the Sun. And this is about 39 trillion kilometers.
In general, all stars are measured in accordance with the Sun (their mass, size, brightness in the spectrum). The distance to such objects is considered in light years or parsec. The latter is approximately 3.26 light years, or 30.85 trillion kilometers.
Astronomy enthusiasts must surely know and understand these numbers.
Stars, like everything in our world, the universe, are born, develop and die, in their case - explode. According to the Harvard scale, they are divided in spectrum from blue (young) to red (old). Our Sun belongs to the yellow, that is, "mature age."
There are also brown and white dwarfs, red giants, variable stars, and many other subtypes. They differ in the content of various metals. Indeed, it is the combustion of various substances due to thermonuclear reactions that makes it possible to measure the spectrum of their radiation.
There are also the names “new,” “supernova,” and “hypernova.” These concepts are not fully reflected in terms. The stars are just old, mostly ending with an explosion. And these words mean only that they were noticed only during the collapse, before that they had not been fixed at all even in the best telescopes.
If you look at the sky from the Earth, clusters are clearly visible. Ancient people gave them names, composed legends about them, put their gods and heroes there. Today we know such names as the Pleiades, Cassiopeia, Pegasus, which came to us from the ancient Greeks.
However, today, scientists distinguish stellar systems. Simply put, imagine that we see not one Sun in the sky, but two, three or even more. Thus, there are double, triple stars and clusters (where there are more luminaries).
Next, we will find out some funny moments that practical astronomy studies. What is a meteorite fashion, and other interesting facts - all of this below.
Entertaining facts
The planet due to various reasons, such as distance from the star, can "go" into outer space. In astronomy, this phenomenon is called the "orphan planet." Although most scientists still insist that they are protostars.
An interesting feature of the starry sky is that in fact it is not what we see it. Many objects exploded long ago and ceased to exist, but were so far away that we still see light from the flash.
Recently, a meteorite search mod has been distributed. How to determine what is in front of you: a stone or a heavenly alien. Entertaining astronomy answers this question.
First of all, a meteorite is denser and heavier than most materials of terrestrial origin. Due to its iron content, it has magnetic properties. Also, the surface of a celestial object will be melted, because during the fall it suffered a severe temperature load due to friction with the Earth’s atmosphere.
We examined the main points of such a science as astronomy. What are stars and planets, the history of discipline and some fun facts you learned from the article.