Astronomy - what is it? The meaning and history of astronomy

Probably, there is not a single person on the whole planet who did not think about incomprehensible flickering dots in the sky that are visible at night. Why does the moon walk around the Earth? All this and even more is studying astronomy. What are planets, stars, comets, when there will be an eclipse and why there are tides in the ocean - these and many other questions are answered by science. 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 way of becoming this discipline. At the current stage of development, it includes several narrower areas.

Astrophysics studies the composition and properties of celestial bodies. The sub-part of it is stellar astronomy.

Celestial mechanics answers questions about the motion and interaction of cosmic objects.

Cosmogony deals with the origin and evolution of the universe.

Thus, today ordinary earth sciences with the help of modern technology can extend the field of research far beyond our planet.

Subject and tasks

In space, it turns out, there are a lot of very diverse bodies and objects. All of them are studied and are, in fact, the subject of astronomy. Galaxies and stars, planets and meteors, comets and antimatter - all this is only one hundredth of the questions that this discipline sets itself.

Recently there was a tremendous opportunity for practical space exploration. Since that time, cosmonautics (or astronautics) proudly became shoulder to shoulder with academic researchers.

This is what humanity dreamed of for a long time. 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 moon - the moon.

Themes of astronomy are not limited to these problems alone. Further we will talk in more detail.

What methods are used to solve problems? The first and oldest of them is observation. The following opportunities appeared only recently. This is spectral analysis, photography, launch of space stations and artificial satellites.

Questions concerning the origin and evolution of the universe, of individual objects, can not yet be sufficiently studied. First, there is not enough accumulated material, and secondly, many bodies are too far away for exact study.

Types of observations

At first, humanity could only boast of the usual visual observation of the sky. But even such a primitive method gave simply amazing results, which we will talk about a little later.

Astronomy and space today are more connected than ever. Objects are studied using the latest technology, which allows many branches of this discipline to develop. Let's get acquainted with them.

Optical method. The oldest version of observation with the help of unarmed eyes, with the participation of binoculars, telescopes, telescopes. This also applies to the newly invented photo.

The next section deals with the registration of infrared radiation in space. With its help fix invisible objects (for example, hidden behind gas clouds) or the composition of celestial bodies.

The importance of astronomy can not be overemphasized, because she answers one of the eternal questions: where did we come from.

The following techniques explore the universe for gamma radiation, X-ray, ultraviolet.

There are also techniques that are 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 the space for the spread of these two actions.
Thus, the types of observations known at the present time have greatly expanded the possibilities of mankind in the exploration of outer space.

Let's look at the process of the formation of this science.

Origin and the first stages of the development of science

In ancient times, at the time of the primitive communal system, people only began to get acquainted with the world and determine phenomena. They tried to realize the change of day and night, the seasons of the year, the behavior of incomprehensible things, such as thunder, lightning, comets. What is the Sun and the Moon - also remained a mystery, so they were considered to be deities.
However, despite this, already in the heyday of the Sumerian kingdom, priests in ziggurats made rather complicated calculations. They divided the visible stars into constellations, singled out the "zodiacal belt" known today, developed a lunar calendar consisting of thirteen months. They also discovered the "Meton cycle", however, a little earlier it was done by the Chinese.

The Egyptians continued and deepened the study of celestial bodies. They generally had an amazing situation. The Nile River is poured in early summer, just at this time on the horizon begins to appear the star Sirius, which hid in the winter months on the firmament of the other hemisphere.

In Egypt, they first began to divide the day for 24 hours. But the week in the beginning was ten days long, that is, the month consisted of three decades.

However, the greatest development of ancient astronomy was in China. Here we managed to calculate the length of the year almost exactly, could predict solar and lunar eclipses, counted comets, sunspots and other unusual phenomena. At the end of the second millennium BC there are first observatories.

The period of antiquity

The history of astronomy in our understanding is impossible without the Greek constellations and terms in celestial mechanics. Although in the beginning the Hellenes were very mistaken, but over time they were able to make fairly accurate observations. The mistake, for example, was that Venus appeared in the morning and evening as two different objects.

The first to pay special attention to this field of knowledge were the Pythagoreans. They knew that the Earth has the shape of a sphere, and day and night are replaced, because it rotates around its axis.

Aristotle was able to calculate the circumference of our planet, though, was mistaken in the larger side twice, but this accuracy was also high for that time. Hipparchus was able to calculate the length of the year, introduced such geographical concepts as latitude and longitude. Made tables of solar and lunar eclipses. On them it was possible to predict these phenomena with an accuracy of up to two hours. Learn from our meteorologists from him!

The last luminary of the ancient world was Claudius Ptolemy. The name of this scientist has been preserved by the history of astronomy forever. The most ingenious 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 the heavenly bodies revolve around it. Thanks to the martial Christianity that came to replace 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, more arguing about how many angels the needle will pierce into the eye. Therefore, the geocentric scheme of the world for many centuries has become the yardstick of truth.

Astronomy of the Indians

The Incas considered the sky a little differently than the rest of the people. Turning to the term, astronomy is the science of the motion and properties of celestial bodies. The Indians of this tribe first of all distinguished 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, going to the west, sank to the bottom of this river and it passed to the eastern part of the sky.

It is well known that the Incas distinguished the following planets - the Moon, Jupiter, Saturn and Venus, and without telescopes they made observations that only Galileo could replicate with the help of optics.

Observatory they 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 time of the year, months was fixed.

Maya, unlike the Incas, developed knowledge very deeply. The bulk of what astronomy studies today, was known to them. They made a very accurate calculation of the duration of the year, the month was divided into two weeks for thirteen days. The beginning of the same chronology was considered 3113 BC.

Thus, we see that in the Ancient World and among the tribes of the "barbarians", as they were considered by "civilized" Europeans, the study of astronomy was at a very high level. Let's see what could boast in Europe after the fall of ancient states.

Middle Ages

Thanks to the diligence of the Inquisition in the late Middle Ages and the poor development of the tribes in the early stage of this period, many sciences have stepped back. If in the era of antiquity people knew what astronomy was studying, and many were interested in such information, then in the Middle Ages theology became more developed. For talking about the fact that the Earth is round, and the Sun is located in the center, it was possible to burn out at the stake. Such words were considered blasphemy, and people were called heretics.

Renaissance, strangely enough, came from the east through the Pyrenees. The Arabs brought to Catalonia the knowledge preserved by their ancestors from the time of Alexander the Great.

In the fifteenth century, Cardinal Cusa expressed the opinion that the universe is infinite, and Ptolemy is mistaken. Such sayings were blasphemous, but very much ahead of time. Therefore, they considered it nonsense.

But the revolution was made by Copernicus, who before his death decided to publish a study of his entire 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 orbit in space. They got their name from the ancient Greek word "wanderer". Why is that? Because to the ancient people they seemed to be traveling stars. The rest stand on usual places, and they move every day.

What is their difference from other objects in the universe? First, the planets are small enough. The size of it allows you to clear your way from 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 due to certain processes they form a dense surface. Thirdly, the planets usually rotate in a particular system around the star or its remains.

Ancient people considered these heavenly bodies to be "messengers" of gods or half-gods, 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 in the center of the universe.

And only Galileo Galilei for the first time with the help of 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 matter was continued.

By definition, the majority recognized today as a planet are only bodies with sufficient mass that revolve around the star. The rest are satellites, asteroids and so on. From the standpoint of science, there are no single people in these ranks.

So, the time for which the planet makes a full circle in its orbit around the star, is called a planetary year. The closest place on its way to the star is the periastre, and the farthest is the apostate.

The second thing that is important to know about the planets is that they have an oblique axis relative to the orbit. Due to this, during rotation of the hemisphere, different amounts of light and radiation from the stars are obtained. So there is a change of seasons, time of day, on the Earth also climatic zones were formed.

Important is that the planets except their path around the star (per year), still revolve around its axis. In this case, the full circle is called "day".
And the last feature of such a celestial body is a pure orbit. For normal functioning, the planet must along the way, colliding with various smaller objects, destroy all "competitors" and travel in proud solitude.

In our solar system there are different planets. Total number of astronomy is eight. The first four belong to the "terrestrial 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 that are called constellations. And yet, it's not for nothing that a whole science - astronomy - has been named in their honor. What is a "star"?

Scientists say that with the naked eye, with a fairly good level of vision, a person can see three thousand celestial objects in each hemisphere.
They have long attracted humanity with their flickering and "unearthly" sense of existence. Let's look at this in more detail.

So, the star is a massive lump of gas, a kind of cloud with a sufficiently high density. Inside it, thermonuclear reactions occur or have occurred before. The mass of such objects allows them to form systems around themselves.

In the study of these cosmic bodies, scientists have identified several ways of classification. You probably heard about the "red dwarfs", "white giants" and other "inhabitants" of the universe. So, for today, one of the most universal classifications is the typology of Morgan-Keenan.

It implies the division of stars in magnitude and spectrum of radiation. In descending order, the groups have names in the form of letters of the Latin alphabet: O, B, A, F, G, K, M. To get you sorted out a little and find the starting point, the Sun, according to this classification, falls into the group "G".

Where do these giants come from? They are formed from the most common gases in the universe - hydrogen and helium, and due to gravitational compression they acquire the final form and weight.

Our star is the Sun, and the closest to us is Centaurus proxim. It is located in the Alpha Centauri system and is located 270 thousand distances from Earth to the Sun from us. 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 parsecs. The latter is approximately 3.26 light years, or 30.85 trillion kilometers.

Lovers of astronomy, of course, should know and understand these figures.
The 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 according to the spectrum from blue (young) to red (old). Our Sun belongs to the yellow, that is, the "mature age".

There are also brown and white dwarfs, red giants, variable stars and many other subtypes. They differ in the level of content of different metals. After all, the combustion of various substances due to thermonuclear reactions makes it possible to measure the spectrum of their radiation.

Also there are names "new", "supernova" and "hypernova". These concepts are not completely reflected in terms. The stars are just old, basically ending their existence with an explosion. And these words mean only that they were noticed only during the collapse, before that they were not fixed at all even in the best telescopes.

If you look at the sky from Earth, the clusters are clearly visible. Ancient people gave them names, made legends about them, placed their gods and heroes there. Today we know such names as the Pleiades, Cassiopeia, Pegasus, who came to us from the ancient Greeks.

However, today scientists are distinguished by star systems. To put it simply, 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 was more light).

Next we learn some funny moments that are being studied by practical astronomy. What is the meteorite fashion, and other interesting facts - about all this below.

Interesting facts

The planet for various reasons, for example, distance from the star, can "go" into open space. In astronomy, this phenomenon was called the "planet-orphan". 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 have exploded long ago and ceased to exist, but were so far away that we still see the light from the flash.

Recently, the fashion for the search for meteorites was spread. How to determine what is before you: a stone or a heavenly stranger. Interesting astronomy answers this question.

First of all, the meteorite is denser and heavier than most materials of terrestrial origin. Due to the iron content, it has magnetic properties. Also, the surface of the celestial object will be melted, because during the fall it suffered a very high temperature load due to friction with the atmosphere of the Earth.

We examined the main points of such a science as astronomy. What are the stars and planets, the history of the formation of discipline and some funny facts you learned from the article.