Heliocentric universe. School encyclopedia. Refusal of geocentrism

The heliocentric system of the world is the idea that the Sun is the center of the universe and the point around which all planets, including the Earth, revolve. This system assumes that our planet performs two types of motion: translational around the Sun and rotational around its axis. The position of the Sun itself relative to other stars is considered unchanged.

The term “heliocentrism” comes from the Greek word “helios” (translated as “Sun”).

It is possible to find a certain central point of the Universe only if the Universe . It owes this according to the heliocentric system of the world.

Also in this system the concept of external and internal planets arose. The latter included Mercury and Venus, because their orbits around the Sun must always be within the Earth's orbit.

The most important feature of heliocentrism is the annual parallaxes of stars. This effect manifests itself in the form of a change in the apparent coordinates of the star. It is associated with a change in the position of observers (astronomers), which arose due to the rotation of the Earth around the Sun.

Heliocentrism in antiquity and the Middle Ages

The idea that the Earth moves around a certain center of the whole world arose in the minds of the ancient Greeks. So there were assumptions about the rotation of the Earth around its axis, as well as about the movement of Mars and Venus around the Sun, which together with them revolves around our planet. However, it is believed that the heliocentric system of the world was first outlined in the 3rd century BC. e. Aristarchus of Samos. He made two important conclusions:

1. Most likely, our planet revolves around the Sun. The reason for this is the size of the Sun, which is significantly larger than the size of the Earth. Data on the relative magnitudes of the Earth, Moon and Sun were obtained from Aristarchus's own calculations.
2. Due to the absence of visible annual parallaxes of stars, he suggested that the orbit of our planet appears to be a point relative to the distances to the stars.

However, Aristarchus' ideas did not become widespread in antiquity. The most famous version of the geocentric system in Ancient Greece was the so-called theory of homocentric spheres, which was developed by the astronomers Eudoxus, Callippus and Aristotle. According to this theory, all celestial bodies revolving around our planet were fixed on rigid spheres, interconnected and having a single center - the Earth.

In connection with such a worldview of the prevailing part of society, other adherents of the idea of ​​Aristarchus of Samos did not express their views, as a result of which the Greeks abandoned this idea and completely accepted geocentrism. Any schools that taught rationalism at that time did not support the ideas of Aristarchus, since they considered the nature of the universe to be beyond understanding and excluded any possibility of describing the dynamics of the planets.

In the Middle Ages, heliocentrism was hardly mentioned in scientific works, except for some of its ideas, for example, the rotation of the Earth on its axis.

Scientific revolution of Nicolaus Copernicus

In 1543, the Polish astronomer, mechanic and clergyman Nicolaus Copernicus published his scientific work, which was called: “On the rotation of the celestial spheres.” In it, the astronomer described the heliocentric theory, confirming it with a number of physical calculations based on the then theoretical mechanics. According to his concept, the change of day and night, as well as the movement of the Sun across the sky, are explained by the rotation of the Earth around its axis. In the same way, with the help of the Earth around the Sun, the movement of our star across the sky throughout the year is explained.

Copernicus explained the following phenomena:

• As a result of the movement of the Earth, which alternately approaches and then moves away from any of the planets of our system, these planets make the so-called. backward movement. That is, after a certain period of time they begin to move in the opposite direction from the direction of the Sun's movement.
• Anticipation of the equinoxes. Over the course of 18 centuries, scientists have been looking for the reasons for such an effect as the anticipation of the equinoxes, according to which every year the spring equinox occurs a little earlier. In his writings, Nicolaus Copernicus was able to describe this effect as a consequence of the periodic displacement of the earth's axis.
• Following in the footsteps of Aristarchus of Samos, Copernicus argued and also proved that the sphere of stars is located at a very large distance relative to the distances between the planets, as a result of which scientists do not observe annual parallaxes. And he confirmed the assumption about the rotation of our planet around its axis with the following: if our planet is still motionless, then the rotation of the sky should occur due to the rotation of the stellar sphere itself, and given the calculated distance to it, the speed of its rotation will be unimaginably high.

In addition, the heliocentric system could explain the change in the brightness and size of the planets of the Solar System, as well as provide a more accurate estimate of the sizes of the planets and the distances to them. Nicolaus Copernicus himself was able to approximately determine the sizes of the Moon and the Sun and indicate as accurately as possible the time during which Mercury completely passes its orbit around the Sun - 88 Earth days.

Despite the complete revolution in the field of astronomy, Copernicus' theory had several shortcomings. Firstly, the central point of the system he described remained the center of the Earth's orbit, and not the Sun. Secondly, all the planets of our planetary system moved unevenly in their orbits, but our planet maintained its orbital speed. And also, most likely, Copernicus did not discard the idea of ​​rotating celestial spheres, but only transferred the center of their rotation.

Followers and opponents of Copernicus

Subsequently, the Polish astronomer gained a large number of followers, including Giordano Bruno, who argued that the firmament is not limited to the celestial spheres, and that other luminaries are celestial bodies in no way inferior to the Sun. Unfortunately, Bruno was labeled a heretic for his beliefs and sentenced to be burned.

The famous Italian scientist supported the Copernican theory, relying on his own observations. He also argued that the Earth never occupied a place between Mercury (or Venus) and the Sun, which indicated the rotation of these two planets around the star in orbits located inside the Earth's. The opposite statement proved the location of the Earth's orbit inside the orbits of the outer planets. Because of his beliefs, the 70-year-old Galileo was subjected to an inquisitorial trial in 1633, which resulted in him being under “house arrest” until his death at 78.

Opponents of heliocentrism insisted on several arguments refuting the Copernican theory. If the Earth rotated around its axis, the monstrous centrifugal force would tear it apart. Moreover, all light objects would fly off its surface, and they would move in the direction opposite to the rotation. It was assumed that all celestial objects have no mass, so they can move without applying large forces to them. In the case of the Earth, the question arose about the existence of a colossal force that could rotate our massive planet.

One of the opponents of geocentrism, the outstanding Danish astronomer Tycho Brahe, developed the so-called “geo-heliocentric” system of the world, according to which the sphere of stars, the Moon and the Sun move around the Earth, and other space objects around the Sun.

After some time, Brahe’s successor, the German physicist Johannes Kepler, having analyzed an impressive volume of observational results from his mentor, made several significant discoveries in favor of heliocentrism:

• The planes of the planetary orbits of the solar system intersect at the location of the sun, which made it the center of their rotation, and not the center of the earth's orbit, as Copernicus assumed.
• The orbital speed of our planet changes periodically, just like other planets.
• The orbits of the planets are elliptical, and the speed of movement of celestial bodies along them directly depended on the distance to the Sun, which made it not only the geometric, but also the dynamic center of the planetary system.

The so-called Kepler's laws were formulated, which described in detail and in mathematical language the laws of motion of the planets of the solar system.

Affirmation of heliocentrism

As a result of confirmation of the rotation of the Earth around its axis, any need for the existence of celestial spheres disappeared. For some time it was assumed that the reason planets move is because they are living things. However, Kepler soon determined that the motion of the planets arises as a result of the influence of the gravitational forces of the Sun on them.

In 1687, the English physicist Isaac Newton, relying on his own, confirmed the calculations of Johannes Kepler

With the further development of science, scientists received more and more arguments in favor of heliocentrism. Thus, in 1728, an astronomer from England, James Bradley, for the first time, using observation, confirmed the theory of the Earth’s orbit around the Sun, discovering the so-called aberration of light. The latter means a slight blurring of the star's image on one side as a result of the movement of the observer. Later, an annual fluctuation in the frequency of pulses emitted by pulsars, as well as for stars, was discovered, which proves a periodic change in the distance of the Earth to these space objects.

And in 1821 and 1837 Russian-German scientist Friedrich Wilhelm Struve was for the first time able to observe the approximate annual parallaxes of stars, which finally confirmed the idea of ​​a heliocentric system of the world.

(heliocentrism) - the idea that the Sun is the central celestial body around which the Earth and other planets revolve. It arose in opposition to the geocentric system of the world in antiquity, but became widespread in the 16th-17th centuries.

In the heliocentric system, the Earth is assumed to rotate around its axis in one sidereal day and at the same time around the Sun in one sidereal year. The consequence of the first movement is the apparent rotation of the celestial sphere, the consequence of the second is the annual movement of the Sun among the stars along the ecliptic. The sun is considered stationary relative to the stars.

Heliocentric reference frame is simply a reference system where the origin of coordinates is located in the Sun. Heliocentric system of the world- this is an idea of ​​​​the structure of the universe. In the narrow sense of this word, it lies in the fact that the Sun is located in the center of the Universe, and the Earth makes at least two types of movement: annual around the Sun and daily around its axis; the stars are stationary relative to the Sun. The term "heliocentric world system" is often used in a broader sense of the word, when the Universe is not necessarily considered limited and having a center. Then the meaning of this term is that the Sun is on average motionless relative to the stars. The heliocentric system of the world can be considered in any reference system, including geocentric, in which the Earth is chosen as the origin of coordinates. In this frame of reference, the Earth is stationary and the Sun rotates around the Earth, but the world system still remains heliocentric, since the mutual configuration of the Sun and stars remains unchanged. On the contrary, even if we consider the geocentric system of the world in a heliocentric frame of reference, it will still be a geocentric system of the world, since the stars will move in it with a period of one year.

The planets of the solar system are divided into two types: internal (Mercury and Venus), observed only at relatively small angular distances from the Sun, and external (all others), which can be observed at any distance. In the heliocentric system, this difference is due to the fact that the orbits of Mercury and Venus are always inside the orbit of the Earth (the third planet from the Sun), while the orbits of the other planets are outside the orbit of the Earth.

All of the above applies not only to the heliocentric system, but also to a combined system (like Tycho Brahe’s system), in which all the planets revolve around the Sun, which, in turn, moves around the Earth. There is, however, evidence of the Earth moving around the Sun.

Even in ancient times it was known that the translational motion of the Earth should lead to an annual parallactic displacement of the stars. Due to the remoteness of the stars, parallaxes were first discovered only in the 19th century (almost simultaneously by V. Ya. Struve, F. Bessel and T. Henderson), which was direct (and long-awaited) evidence of the Earth’s movement around the Sun.

The retrograde motions of the planets occur for the same reason as the annual parallaxes of stars; they can be called the annual parallaxes of the planets.

Due to the vector addition of the speed of light and the orbital speed of the Earth, when observing stars, the telescope must be tilted relative to the Earth-star line. This phenomenon (light aberration) was discovered and correctly explained in 1728 by James Bradley, who was searching for annual parallaxes. The aberration of light turned out to be the first observational confirmation of the Earth’s motion around the Sun and at the same time the second proof of the finiteness of the speed of light (after Roemer’s explanation of the irregularity in the motion of Jupiter’s satellites). Unlike parallax, the angle of aberration does not depend on the distance from the star and is entirely determined by the orbital speed of the Earth. For all stars it is equal to the same value: 20.5".

Due to the orbital motion of the Earth, each star located near the ecliptic plane either approaches or moves away from the Earth, which can be detected using spectral observations (the Doppler effect).

A similar effect is observed for the temperature of the cosmic microwave background radiation - at each point of the ecliptic, due to the movement of the Earth around the Sun, it changes with a period of 1 year.

Evidence of the Earth's rotation on its axis see the article Daily rotation of the Earth.

The idea of ​​the Earth's motion originated within the Pythagorean school. The Pythagorean Philolaus of Croton promulgated a system of the world in which the Earth is one of the planets; however, so far we have been talking about its rotation (per day) around the mystical Central Fire, and not the Sun. Aristotle rejected this system, among other things, because it predicted the parallactic displacement of stars.

Less speculative was the hypothesis of Heraclides of Pontus, according to which the Earth rotates daily on its axis. In addition, Heraclides apparently suggested that Mercury and Venus revolve around the Sun and only with it around the Earth. Perhaps Archimedes also held this view, believing that Mars was also revolving around the Sun, whose orbit in this case should have embraced the Earth, and not run between it and the Sun, as in the case of Mercury and Venus. There is an assumption that Heraclides had a theory according to which the Earth, the Sun and the planets revolve around one point - the center of the planetary system. According to Theophrastus, Plato, in his declining years, regretted that he had given the Earth a central place in the Universe that was not suitable for it.

A truly heliocentric system was proposed at the beginning of the 3rd century BC. e. Aristarchus of Samos. Scarce information about Aristarchus's hypothesis has reached us through the works of Archimedes, Plutarch and other authors. It is usually believed that Aristarchus came to heliocentrism based on the fact that he established that the Sun is much larger in size than the Earth (the only work of a scientist that has come down to us is devoted to calculating the relative sizes of the Earth, Moon and Sun). It was natural to assume that the smaller body revolves around the larger one, and not vice versa. The extent to which Aristarchus’s hypothesis was developed is unknown, but Aristarchus made an important conclusion that, compared with the distances to the stars, the earth’s orbit is a point, since otherwise the annual parallaxes of the stars should have been observed (following Aristarchus, Archimedes also accepted such an assessment of the distances to the stars). The philosopher Cleanthes called for Aristarchus to be brought to trial for moving the Earth (“The Hearth of the World”).

Heliocentrism made it possible to solve the main problems facing ancient Greek astronomy, since they were dominant at the beginning of the 3rd century BC. e. geocentric views were clearly in a state of crisis. The most common version of geocentrism at that time, the theory of homocentric spheres of Eudoxus, Callippus and Aristotle, was unable to explain the change in the apparent brightness of the planets and the apparent size of the Moon, which the Greeks correctly associated with a change in the distance to these celestial bodies. The heliocentric system easily explained the retrograde movements of the planets. It also made it possible to establish the order of the luminaries. The Greeks postulated a relationship between the proximity of a celestial body to the “sphere of fixed stars” and the sidereal period of its movement: thus, the slowest moving Saturn was considered the farthest from us, followed (in order of approach to the Earth) by Jupiter and Mars; The Moon turned out to be the celestial body closest to the Earth. The difficulties of this scheme were associated with the Sun, Mercury and Venus, since all these bodies had the same sidereal periods (in the sense used in ancient astronomy), equal to one year. This difficulty was easily solved in the heliocentric system, where one year turned out to be equal to the period of the Earth's motion; at the same time, the periods of movement (now - revolution around the Sun) of Mercury and Venus were in the same order as their distances to the new center of the world, which could be established in the manner described above.

Among the direct supporters of Aristarchus' hypothesis, only the Babylonian Seleucus (first half of the 2nd century BC) is mentioned, who, according to Plutarch, provided its evidence. From this it is usually concluded that heliocentrism had no other supporters, that is, it was not accepted by Hellenic science. However, the very mention of Seleucus as a follower of Aristarchus is very significant, since it means the penetration of heliocentrism even onto the banks of the Tigris and Euphrates, which in itself indicates the widespread popularity of the idea of ​​​​the movement of the Earth. Moreover, Sextus Empiricus mentions the followers of Aristarchus in the plural. A fairly favorable review of Aristarchus’s hypothesis in Archimedes’ work “Psammit” (the main source of our information about this hypothesis) suggests that Archimedes at least did not exclude this hypothesis. A number of authors have argued for the widespread prevalence of heliocentrism in antiquity. It is possible, in particular, that the geocentric theory of planetary motion, set forth in Ptolemy’s Almagest, is a revised heliocentric system. The Italian mathematician Lucio Russo provided a number of evidence about the development in the Hellenistic era of the dynamics of the heliocentric system based on the general idea of ​​​​the law of inertia and the attraction of planets to the Sun.

However, heliocentrism was eventually abandoned by the Greeks. The main reason may be the general crisis of science that began after the 2nd century BC. e. Astrology takes the place of astronomy. Philosophy is dominated by mysticism or overt religious dogmatism: Stoicism, later Neopythagoreanism and Neoplatonism. On the other hand, those few philosophical schools that generally profess rationalism (Epicureans, skeptics) have one thing in common: disbelief in the possibility of knowing nature. Thus, the Epicureans, even after Aristotle and Aristarchus, considered it impossible to determine the true cause of the phases of the Moon and considered the Earth to be flat. In such an atmosphere, religious accusations such as those brought against Aristarchus could lead to the fact that astronomers and physicists, even if they were supporters of heliocentrism, tried to refrain from publicly publishing their views, which could ultimately lead to their oblivion.

For scientific arguments in favor of the immobility and centrality of the Earth put forward by ancient Greek astronomers, see the article Geocentric system of the world.

After the 2nd century AD e. in the Hellenistic world, geocentrism was firmly established, based on the philosophy of Aristotle and the planetary theory of Ptolemy, in which the looping motion of the planets was explained using a combination of deferents and epicycles. The “physical” foundation of Ptolemy’s theory was the Aristotelian theory of the celestial spheres that transported the planets. An essential feature of Aristotle’s teaching was the sharp contrast between the “supralunar” and “sublunar” worlds. The superlunar world (where all celestial bodies belonged) was considered an ideal world, not subject to any changes. On the contrary, everything that was in the sublunar region, including the Earth, was considered subject to constant change and corruption.

An essential feature of Ptolemy's theory was a partial rejection of the principle of uniformity of cosmic motions: the center of the epicycle moves along the deferent with a variable speed, although the angular velocity when observed from a special eccentrically located point (equant) was considered unchanged.

System of the world in which Mercury and Venus orbit the Sun (1573 image)

Currently, the dominant view is that the source of Indian medieval astronomy is Greek pre-Ptolemaic astronomy. According to Van der Waerden, the Greeks had a heliocentric theory, developed to the point of being able to calculate the ephemerides of the planets, which was then developed into a geocentric one (similar to what Tycho Brahe did with the Copernican theory). This revised theory must inevitably be a theory of epicycles, since in the reference frame associated with the Earth, the movement of the planets objectively occurs according to a combination of movements along the deferent and the epicycle. Further, according to van der Waerden, it penetrated into India. Aryabhata himself and later astronomers may not have known about the heliocentric basis of this theory. Subsequently, according to van der Waerden, this theory passed on to Muslim astronomers, who compiled the “Shah Tables” - ephemeris of the planets used for astrological predictions.

Al-Biruni spoke sympathetically about Aryabhata's assumption about the daily rotation of the Earth. But he himself, apparently, ultimately leaned towards the immobility of the Earth.

A number of astronomers in the Muslim East discussed alternative theories of planetary motion to the Ptolemaic one. The main object of their criticism was, however, the equant, and not geocentrism. Some of these scholars (for example, Nasir ad-Din al-Tusi) also criticized Ptolemy's empirical arguments for the immobility of the Earth, finding them inadequate. But at the same time they remained supporters of the immobility of the Earth, since this was consistent with the philosophy of Aristotle.

The exception is the astronomers of the Samarkand school, which consisted of the Ulugbek madrasah and his observatory (the first half of the 15th century). Thus, al-Kushchi rejected the philosophy of Aristotle as the physical foundation of astronomy and considered the rotation of the Earth around its axis to be physically possible. There are indications that some of the Samarkand astronomers considered the possibility of not just the axial rotation of the Earth, but the movement of its center, and also developed a theory in which the Sun is considered to revolve around the Earth, but all the planets revolve around the Sun (geo-heliocentric system of the world).

In Europe, the possibility of the Earth rotating around its axis has been discussed since the 12th century. In the second half of the 13th century, this hypothesis was mentioned by Thomas Aquinas, along with the idea of ​​​​the forward motion of the Earth (without specifying the center of motion). Both hypotheses were rejected for the same reasons as Aristotle. The hypothesis of the axial rotation of the Earth was discussed in depth by representatives of the School of Paris in the 14th century (Jean Buridan and Nicholas Oresme). Although during these discussions a number of arguments were rebutted by opponents of the Earth's mobility, the final verdict was in favor of its immobility.

The movement of the Earth was also mentioned at the turn of the 15th and 16th centuries. In 1499, this hypothesis was discussed by the Italian professor Francesco Capuano (English), and this meant not only the rotational, but also the translational motion of the Earth (without specifying the center of motion). Both hypotheses were rejected for the same reasons as those of Aristotle and Thomas Aquinas. In 1501, the Italian humanist Giorgio Valla mentioned the Pythagorean doctrine of the Earth's motion around a Central Fire and argued that Mercury and Venus revolve around the Sun.

Heliocentrism was finally revived only in the 16th century, when the Polish astronomer Nicolaus Copernicus developed the theory of planetary motion around the Sun based on the Pythagorean principle of uniform circular motion. He published the results of his work in the book “On the Rotations of the Celestial Spheres,” published in 1543. One of the reasons for the return to heliocentrism was Copernicus's disagreement with the Ptolemaic theory of the equant; in addition, he considered the disadvantage of all geocentric theories to be that they do not allow one to determine “the shape of the world and the proportionality of its parts,” that is, the scale of the planetary system. It is unclear what influence Aristarchus had on Copernicus (in the manuscript of his book, Copernicus mentioned Aristarchus' heliocentrism, but this reference disappeared in the final edition of the book).

Copernicus's theory of the motion of the outer planets. S - Sun, P - planet, U - center of the planet's orbit. The quadrilateral UEPD remained an isosceles trapezoid. The movement of the planet from point E of the equant looks uniform (the angle between the segment EP and the line of apses SO changes uniformly). Thus, this point plays approximately the same role in the Copernican system as the equant point in the Ptolemaic system

Copernicus not only explained the reasons for the retrograde movements of the planets, he calculated the distances of the planets from the Sun and the periods of their revolutions. Copernicus explained the zodiacal inequality in the movement of the planets by the fact that their movement is a combination of movements in large and small circles - similar to how medieval astronomers of the East - figures of the Maragha Revolution - explained this inequality (thus, Copernicus’s theory of the movement of the outer planets coincided with the theory of Al- Urdi, theory of the movement of Mercury - with the theory of Ibn al-Shatir, but only in the heliocentric frame of reference).

However, Copernicus’ theory cannot be called heliocentric in full, since the Earth in it partially retained a special status:

Apparently, Copernicus maintained his belief in the existence of celestial spheres bearing planets. Thus, the movement of the planets around the Sun was explained by the rotation of these spheres around their axes.

The first printed image of the Solar System (page from Copernicus's book)

Nevertheless, they were given impetus for the further development of the heliocentric theory of planetary motion and related problems of mechanics and cosmology. By declaring the Earth one of the planets, Copernicus created the conditions for eliminating the sharp gap between the “supralunar” and “sublunar” worlds, characteristic of the philosophy of Aristotle and medieval scholasticism.

The leading trend in the perception of Copernicus' theory throughout the 16th century was the use of the mathematical apparatus of his theory for astronomical calculations and the almost complete ignorance of his new, heliocentric cosmology. This trend began with the preface to the book of Copernicus, written by its publisher, the Lutheran theologian Andreas Osiander. Osiander writes that the movement of the Earth is an ingenious computational device, but Copernicus should not be taken literally. Since Osiander did not indicate his name under the preface, many in the 16th century believed that this was the opinion of Nicolaus Copernicus himself. Copernicus’s book was studied by astronomers at the University of Wittenberg, the most famous of whom was Erasmus Reinhold, who welcomed the author’s rejection of the equant and compiled new tables of planetary motions (“Prussian Tables”) based on his theory. But neither Reinhold nor the other Wittenberg astronomers seemed to notice the main thing that Copernicus had - a new cosmological system.

Almost the only scientists of the first three decades after the publication of the book On the rotations of the celestial spheres who accepted Copernicus' theory was the German astronomer Georg Joachim Rheticus, who at one time collaborated with Copernicus, considered himself his student and even published (even before Copernicus, in 1540) a work outlining the new system of the world, as well as the astronomer and geodesist Gemma Frisius. His friend, Bishop Tiedemann Giese, was also a supporter of Copernicus.

And only in the 70s - 90s of the 16th century. Astronomers began to show interest in the new system of the world. It is outlined and defended by astronomers Thomas Digges, Christoph Rothman and Michael Möstlin, and physicist Simon Stevin. An outstanding contribution to the development of heliocentrism was made by the philosopher Giordano Bruno, who was one of the first to abandon the dogma of the existence of solid celestial spheres. Theologian Diego de Zuniga (English) used the idea of ​​the movement of the Earth to interpret some words of the Bible. Perhaps the heliocentrists of this period also included famous scientists Giambatista Benedetti, William Gilbert, Thomas Herriot. Some authors, rejecting the translational motion of the Earth, accepted its rotation around its axis: astronomer Nicholas Reimers (Ursus), philosopher Francesco Patrizi. The well-educated French poet and philosopher Pontus de Thiard had a rather positive attitude towards Copernicus’ theory, arguing that each of the stars is an inhabited world similar to Earth.

At the same time, the first negative reviews about Copernicus’ theory began to appear. The most authoritative opponents of heliocentrism in the 16th and early 17th centuries were astronomers Tycho Brahe and Christopher Clavius, mathematicians François Viète and Francesco Mavrolico, and philosopher Francis Bacon.

Opponents of the heliocentric theory had two types of arguments (in “Dialogues on the Two Systems of the World” Galileo sets them out and then criticizes Salviati).

(A) Against the rotation of the Earth around its own axis. Scientists of the 16th century could already estimate the linear speed of rotation: about 500 m/sec at the equator.

These arguments were based on Aristotle's mechanics, which were generally accepted in those years. They lost their power only after the discovery of the laws of Newtonian mechanics. On the other hand, such fundamental concepts of this science as centrifugal force, relativity, inertia appeared to a large extent in refuting these arguments of geocentrists.

To refute the second argument, heliocentrists had to assume the enormous distance of the stars. Quietly Brahe objected to this that in this case the stars turn out to be unusually large, larger in size than the orbit of Saturn. This estimate followed from his determination of the angular sizes of stars: he assumed the apparent diameter of first magnitude stars to be approximately 2-3 arc minutes.

Tycho Brahe proposed a compromise geo-heliocentric system of the world, in which the stationary Earth is at the center of the world, the Sun, Moon and stars revolve around it, but the planets revolve around the Sun. Since the end of the 16th century. It is this combined system of the world (essentially a modernized form of geocentric theory) that becomes the main competitor to heliocentrism.

An outstanding contribution to the development of heliocentric ideas was made by the German astronomer Johannes Kepler. Since his student years (at the end of the 16th century), he was convinced of the validity of heliocentrism due to the ability of this doctrine to provide a natural explanation for the retrograde motion of the planets and the ability to calculate the scale of the planetary system on its basis. For several years, Kepler worked with the greatest observational astronomer, Tycho Brahe, and subsequently became the owner of his archive of observational data. During the analysis of these data, showing exceptional physical intuition, Kepler came to the following conclusions:

Finding himself in the same Copernican camp as Kepler, Galileo never accepted his laws of planetary motion. This also applies to other heliocentrists of the first third of the 17th century, for example, the Dutch astronomer Philip van Lansberg. However, astronomers of a later time could clearly verify the accuracy of Kepler’s “Rudolfin Tables”. Thus, one of Kepler’s predictions was the passage of Mercury across the disk of the Sun in 1631, which the French astronomer Pierre Gassendi actually managed to observe. Kepler's tables were further refined by the English astronomer Jeremy Horrocks, who predicted the passage of Venus across the disk of the Sun in 1639, which he observed together with another English astronomer, William Crabtree.

However, even the phenomenal accuracy of Kepler’s theory (substantially refined by Horrocks) did not convince the skeptics-geocentrists, since many problems of the heliocentric theory remained unresolved. First of all, this is the problem of annual parallaxes of stars, the search for which was carried out throughout the 17th century. Despite the significant increase in measurement accuracy (which was achieved through the use of telescopes), these searches remained unsuccessful, which indicated that the stars were even further away than Copernicus, Galileo and Kepler had assumed. This, in turn, again put on the agenda the problem of star sizes, noted by Tycho Brahe. Only at the end of the 17th century did scientists realize that what they had taken to be stellar disks was in fact a purely instrumental effect (Airy disk): stars have such small angular sizes that their disks cannot be seen even with the most powerful telescopes.

In addition, there were still physical objections to the movement of the Earth, based on Aristotelian mechanics. Galileo's ideas about inertia and relativity did not convince all scientists of the 17th century. Among the opponents of heliocentrism, the Jesuit Riccioli, a deservedly famous astronomer of his time, stood out. In his fundamental work “New Almagest”, he listed and discussed 49 evidence in favor of Copernicus and 77 against it (which, however, did not stop him from naming one of the lunar craters after Copernicus).

The main competitor of the heliocentric theory in those days was no longer the theory of Ptolemy, but the geo-heliocentric system of the world, supplemented by the assumption of ellipticity of orbits. The Copernican system was supported by a number of prominent scientists of the 17th century. A number of scientists (Isaac Beckman, Jeremy Horrocks, Rene Descartes, Gilles Roberval, Giovanni Alfonso Borelli, Robert Hooke) tried to build theories of planetary motion based on the principles of mechanistic philosophy. Among the supporters of heliocentrism in the 17th century were also outstanding scientists Otto von Guericke, Ismael Bulliald, Christian Huygens, John Wilkins, John Wallis.

However, until the end of the 17th century, many scientists simply refused to choose between these hypotheses, pointing out that from an observational point of view, the heliocentric and geo-heliocentric system systems are equivalent; Of course, remaining in this position, it was impossible to develop the dynamics of the planetary system. Among the supporters of this “positivist” point of view were, for example, Giovanni Domenico Cassini, Ole Roemer, Blaise Pascal.

It must be added that in disputes with geocentrists, supporters of Aristarchus and Copernicus were by no means on an equal footing, since the former had such authority as the Church on their side (especially in Catholic countries). However, after Isaac Newton deduced Kepler’s laws from the law of universal gravitation in 1687, all disputes about the system of the world, which had not subsided for a century and a half, lost their meaning. The Sun firmly occupied the center of the planetary system, finding itself one of many stars in the endless Universe.

The advancement of the heliocentric system significantly stimulated the development of physics. First of all, it was necessary to answer the question why the movement of the Earth is not felt by people and is not manifested in earthly experiments. It was on this path that the fundamental principles of classical mechanics were formulated: the principle of relativity and the principle of inertia. Nicholas Oresme, Ali al-Kushchi, Nicholas of Cusanus, Copernicus, Thomas Digges, Giordano Bruno wrote about the impossibility of distinguishing between motion and rest using the example of the hypothesis of the Earth’s motion around its axis. An outstanding step in formulating the principle of relativity was made by Galileo Galilei.

The physical basis of geocentric cosmology was the theory of nested spheres, in which the planets are carried in their motion by solid celestial spheres. Firstly, the daily trajectories of stars are as if they were tied to a single sphere rotating around the Earth during a sidereal day. Secondly, without involving the idea of ​​solid spheres to which the planets are attached, it was almost impossible to give a physical interpretation of the Ptolemaic epicycles.

However, within the framework of heliocentrism, there is no need for the celestial spheres, because if the visible daily movements of the stars are due to the daily rotation of the Earth, then the external celestial sphere, which carries the stars, is simply unnecessary. However, this sphere is only the outer boundary of the entire system of spheres to which the planets are attached. Thus, if the external sphere does not exist, then this entire system of celestial spheres turns out to be unnecessary. Giordano Bruno was the first to draw attention to this (“The Ash Meal”, 1584).

Title page of Kepler's "New Astronomy" - the book in which the hypothesis about the movement of planets under the influence of forces emanating from the Sun was first put forward

Then the question arose about what (if not spheres) moves the planets. Bruno, like many other scientists (in particular, Tycho Brahe, William Gilbert) believed that the planets are living, intelligent beings that are moved by their own souls. For some time, Kepler also held this opinion, but in the process of constructing the theory of the movement of Mars, he came to the conclusion that the movement of the planets is controlled by forces emanating from the Sun (“New Astronomy”, 1609). In his theory there were three such forces: one pushes the planet in orbit, acting tangentially to the trajectory (due to this force the planet moves), the other either attracts or pushes the planet away from the Sun (due to it the planet’s orbit is an ellipse) and the third acts across the ecliptic plane (due to which the planet’s orbit lies in a plane that does not coincide with the ecliptic plane). He considered the first of them (“circular” force) to decrease in inverse proportion to the distance from the Sun.

Not all scientists agreed with Kepler's opinion. Thus, Galileo identified the motion of planets with inertial motion. The Keplerian theory was also rejected by the leading theoretical astronomer of the mid-17th century, Ismael Bulliald, according to whom the planets move around the Sun not under the influence of forces emanating from it, but as a result of some internal desire. In addition, if a circular force existed, it would decrease inversely to the second power of distance, and not to the first, as Kepler believed. However, the search for a dynamical explanation of planetary motions was supported by Jeremy Horrocks and Isaac Beckman. Descartes believed that the planets were carried around the Sun by giant vortices. Kepler's opinion about the motion of planets under the influence of the Sun was supported by J. A. Borelli (“Theory of the Medicean Planets,” 1666). In his opinion, three forces emanate from the Sun: one propels the planet along its orbit, the other attracts the planet to the Sun, and the third (centrifugal), on the contrary, pushes the planet away. The planet's elliptical orbit is the result of the opposition of the latter two.

The movement of planets as a superposition of falling on the Sun and movement by inertia (according to R. Hooke)

Kepler did not agree with these views. He imagined the Universe as a ball of finite radius with a cavity in the middle where the Solar system was located. Kepler considered the spherical layer outside this cavity to be filled with stars - self-luminous objects, but of a fundamentally different nature than the Sun. One of his arguments is an immediate precursor to the photometric paradox. On the contrary, Galileo, leaving open the question of the infinity of the Universe, considered the stars to be distant suns. In the mid to second half of the 17th century, these views were supported by René Descartes, Otto von Guericke and Christiaan Huygens. Huygens, as well as J. Gregory and I. Newton, made the first attempts to determine the distance to stars based on the assumption that their luminosity is equal to the sun.

Even sharing the opinion that the nature of the Sun and stars is identical, many scientists believed that the totality of stars occupies only part of space, beyond which there is emptiness or ether. However, at the beginning of the 18th century, Isaac Newton and Edmond Halley spoke out in favor of uniformly filling space with stars, since if the system of stars was finite, they would inevitably fall on each other under the influence of mutual gravitational forces. Thus, the Sun, while remaining the center of the planetary system, ceased to be the center of the world, all points of which were in equal conditions.

Almost immediately after the heliocentric system was put forward, it was noted that it contradicts some passages of Holy Scripture. For example, an excerpt from one of the Psalms

You have set the earth on firm foundations: it will not be shaken forever and ever (Ps.).

was cited as proof of the immobility of the Earth. Several other passages have been cited to support the idea that it is the Sun and not the Earth that makes the diurnal movement. Among them, for example, is one passage from the Book of Ecclesiastes:

The sun rises and the sun sets, and hastens to its place where it rises (Ecc.).

Jesus cried to the Lord on the day that the Lord delivered the Amorites into the hands of Israel, when he defeated them in Gibeon, and they were beaten before the children of Israel, and said before the Israelites: Stand, O sun, over Gibeon, and the moon, over the valley of Avalon. )! (Nav.)

Since the command to stop was given to the Sun, and not to the Earth, it was concluded that it was the Sun that performed the daily movement. Religious arguments were used to support their positions not only by Catholic and Protestant leaders, but also by professional astronomers (Tycho Brahe, Christopher Clavius, Giovanni Battista Riccioli, etc.).

Proponents of the Earth's rotation pursued a two-pronged defense. First, they pointed out that the Bible was written in a language understandable to ordinary people, and if its authors provided scientifically clear language, it would not be able to fulfill its main, religious mission. In addition, it was noted that some passages of the Bible should be interpreted allegorically (see the article Biblical allegorism). Thus, Galileo noted that if Holy Scripture is taken literally in its entirety, it will turn out that God has hands, is subject to emotions such as anger, etc. In general, the main idea of ​​the defenders of the doctrine of the movement of the Earth was that science and religion have different goals: science examines the phenomena of the material world, guided by the arguments of reason, the goal of religion is the moral improvement of man, his salvation. ; as a token of gratitude, Pope Clement VII, who was present there, presented the speaker with a valuable ancient Greek manuscript. Three more years later, Cardinal Nicholas Schomberg wrote a letter to Copernicus, in which he strongly recommended that he quickly publish a book with a detailed presentation of his theory. Copernicus was also persistently urged by his close friend, Bishop Tiedemann Giese, to promulgate the new system of the world.

However, already in the first years after the publication of Copernicus’s book, one of the high-ranking Vatican officials, the manager of the Papal Palace, Bartolomeo Spina, called for a ban on the heliocentric system, although he did not manage to achieve his goal due to serious illness and death. Theologians began to realize the danger of the new world system for the Church only at the end of the 16th century. Thus, arguments based on the Bible in favor of the immobility of the Earth were heard at the trial against the “until correction”, subject to censorship (1620), the Catholic Church began to consider any attempts to declare the heliocentric theory a real reflection of the movement of the planets (and not just a mathematical model) as contrary to the basic provisions of faith.

In the second half of the 20s of the 17th century, Galileo considered that the situation was gradually defusing and published his famous work “Dialogues on the two most important systems of the world, Ptolemaic and Copernican” (1632). Although censorship allowed the publication of the “Dialogue”, very soon the Pope Urban VIII considered the book heretical, and Galileo was brought before the Inquisition. In 1633 he was forced to publicly renounce his views.

Johannes Kepler was forced to answer questions about the compatibility of the heliocentric system with Scripture from the leaders of Protestant communities.

However, in Protestant countries the situation was much more liberal than in Catholic ones, especially in Britain. Opposition to Catholics, as well as the lack of a unified religious leadership among Protestants, may have played a certain role here. As a result, it was the Protestant countries (along with France) that became the leaders of the scientific revolution of the 17th century.

Empress Elizabeth.

Beginning with the reign of Catherine II (1762), restrictions on the promotion of Copernicanism were lifted, heliocentrism was included in school textbooks, and open protests by the clergy against this system of the world ceased. After the Patriotic War of 1812, in connection with the general religious upsurge, several anti-Copernican works appeared in Russia, but they did not have serious consequences. For example, in 1815, with the approval of censorship, an anonymous treatise “The Destruction of the Copernican System” was published, in which the author called the heliocentric system a “false philosophical system” and “outrageous opinion” criticized the heliocentric system of the world until the beginning of the 20th century. Old Believer Copernicus.

However, as it was realized that the Copernican system contradicted not only Ptolemy, but also the Talmud and the simple meaning of the Bible, the Copernican system began to have opponents. For example, Rabbi Tuvia Hakohen of Metz calls Copernicus “the firstborn of Satan,” since he contradicts the verses from Ecclesiastes: “But the earth stands forever” (Ecc.).

In later times, direct attacks on the heliocentric system among Jews were practically not observed, but doubts were periodically expressed as to how much one could trust science in general and the heliocentric system in particular. In some sources XVIII

Two Astronomers happened together at a feast
And they argued quite among themselves in the heat.
One repeated: The Earth, spinning, moves around the circle of the Sun;
Another is that the Sun takes all the planets with it.
One was Copernicus, the other was known as Ptolemy.
Here the cook settled the dispute with his smile.
The owner asked: “Do you know the course of the stars?
Tell me, how do you reason about this doubt?”
He gave the following answer: “What is Copernicus right about that?
I will prove the truth without having been to the Sun.
Who has seen a simpleton among cooks like this?
Who would turn the fireplace around the roaster?

A number of books and films are dedicated to the life of the founder of the heliocentric system - Nicolaus Copernicus and its supporters Giordano Bruno and Galileo Galilei.

The album is dedicated to the formation of heliocentrism Heliocentric German rock band "The Ocean".

The heliocentric system of the world, put forward in the 3rd century BC. e. Aristarchus and revived in the 16th century by Copernicus, made it possible to establish the parameters of the planetary system and discover the laws of planetary motions. The substantiation of heliocentrism required the creation of classical mechanics and led to the discovery of the law of universal gravitation. Heliocentrism opened the way to stellar astronomy (stars are distant suns) and cosmology of the infinite Universe. The scientific debate surrounding the heliocentric system contributed to the demarcation of science and religion, making arguments based on Scripture no longer accepted as arguments in scientific debate.

Shaka Alesya

The emergence of judgments about the structure of the Universe. Supporters and opponents of systems. Scientific rationale.

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Geocentric and heliocentric systems of the world Supporters and opponents The work was done by a 7th grade student of GBOU Secondary School No. 1465 Shaka Alesey Physics teacher L.Yu. Kruglova

Geocentric system

Geocentric system “From ancient times, people have tried to explain the structure of the world, to understand the place of humanity in the Universe. The earliest theory was the geocentric system of the world.” Geocentric system of the world. (from the Greek "geo" - earth) The Geocentric World System, also known as the Ptolemaic System, is a theory that was developed by philosophers in Ancient Greece and named after the philosopher Claudius Ptolemy, who lived from approximately 90 to 168 AD. It was developed to explain how the planets, the Sun and even the stars orbit the Earth. The geocentric system of the world existed even before Ptolemy. This model was described in various ancient Greek manuscripts, and even in the 4th century BC. Plato and Aristotle wrote about the geocentric system of the world.

Geocentric system Since ancient times, the Earth has been considered the center of the universe, and at different times it was believed that some mythical creature held the earth. Thales of Miletus saw a natural object as this support - the world ocean. Anaximander of Miletus suggested that the Universe is centrally symmetric and does not have any distinguished direction. Therefore, the Earth, located in the center of the Cosmos, has no reason to move in any direction, that is, it rests freely in the center of the Universe without support. Anaximander's student Anaximenes did not follow his teacher, believing that the Earth was kept from falling by compressed air. Anaxagoras was of the same opinion. Anaximander's point of view was shared by the Pythagoreans, Parmenides and Ptolemy. The position of Democritus is not clear: according to various evidence, he followed Anaximander or Anaximenes.

In the 2nd century BC. The ancient Greek astronomer Hipparchus, observing the movement of the planets, discovered a phenomenon called precession - the reverse movement of the planets. He noticed that the planets, as they moved, seemed to describe loops across the sky. This movement of planets across the sky is due to the fact that we observe the planets from the Earth, which itself moves around the Sun. When the Earth “catches up” with another planet, it seems that the planet stops and then moves in the opposite direction.

The ancient Greek astronomer Ptolemy (100-165) put forward his own system of the universe, called geocentric. His reasoning was as follows. Since the Universe has a center, i.e. the place where all bodies with weight strive, then, consequently, the Earth must be located together with these bodies. Otherwise, the Earth, being heavier than all other bodies, would fall towards the center of the world, overtaking in its movement all objects on its surface: people, animals, trees, utensils - which would float in the air. And since the Earth does not fall, it means that it is the motionless center of the Universe. Ptolemy introduced well-known improvements - the concepts of epicycle and deferent. He assumed that the planet moves along a small circle - an epicycle with a constant speed, and the center of the epicycle, in turn, moves along a large circle - a deferent. Thus, he reasoned that each of the planets does not move around the Earth, but around a certain point, which, in turn, moves in a circle (deferent), in the center of which the Earth is located.

Ptolemy added another element to his system - the equant, thanks to which the planets could already move unevenly in a circle, but subject to the existence of a certain point from which this movement would seem uniform. Despite all the complexity and initial theoretical incorrectness of the concept, Ptolemy, painstakingly selecting for each planet a unique combination of deferents, epicycles and equants, ensured that his system of the world predicted the position of the planets quite accurately. This was the genius of his time. The calculations made by Ptolemy were very important for his contemporaries; they made it possible to draw up calendars, help travelers navigate their way, and served as a schedule of agricultural work for farmers. Such a system of the universe was considered correct for almost one and a half thousand years. After some time, astronomers discovered discrepancies between the observed positions of the planets and those previously calculated, but for centuries they thought that Ptolemy’s geocentric system of the world was simply not perfect enough and attempted to improve it - introducing more and more new combinations of circular motions for each planet.

Heliocentric system

Heliocentric system In turn, the geocentric system of the world was replaced by a heliocentric system. Heliocentric system of the world. (from the Greek helio - Sun) The heliocentric system of the world is a theory that places the Sun at the center of the Universe, and the planets in orbit around it. The heliocentric world system replaced geocentrism (geocentric world system), which was the belief that the Earth was the center of the universe. The geocentric world system was the dominant theory in ancient Greece, throughout Europe and other parts of the world for centuries. It was until the 16th century that the heliocentric world system began to gain popularity because technology had advanced enough to provide more evidence in its favor. Although heliocentrism did not gain popularity until the 1500s, the idea has existed for centuries throughout the world.

The great Polish astronomer Nicolaus Copernicus (1473-1543) outlined his system of the world in the book “On the Rotations of the Celestial Spheres,” published in the year of his death. In this book, he proved that the Universe is not structured at all as religion has claimed for many centuries. In all countries, for almost a millennium and a half, the false teaching of Ptolemy, who claimed that the Earth rests motionless in the center of the Universe, dominated the minds of people. Ptolemy's followers, to please the church, came up with new “explanations” and “proofs” of the movement of the planets around the Earth in order to preserve the “truth” and “holiness” of his false teaching. But this made Ptolemy’s system become more and more far-fetched and artificial.

An outstanding contribution to the development of heliocentric ideas was made by the German astronomer Johannes Kepler. Since his student years (at the end of the 16th century), he was convinced of the validity of heliocentrism due to the ability of this doctrine to provide a natural explanation for the retrograde motion of the planets and the ability to calculate the scale of the planetary system on its basis. For several years, Kepler worked with the greatest observational astronomer, Tycho Brahe, and subsequently acquired his archive of observational data.

At the same time as Kepler, at the other end of Europe, in Italy, Galileo Galilei worked, who provided double support for the heliocentric theory. Firstly, with the help of the telescope he invented, Galileo made a number of discoveries that either indirectly confirmed the theory of Copernicus, or knocked the ground out from under the feet of his opponents - supporters of Aristotle

Another equally famous scientist of antiquity, Democritus - the founder of the concept of atoms, who lived 400 years BC - believed that the Sun is many times larger than the Earth, that the Moon itself does not glow, but only reflects sunlight, and the Milky Way consists of a huge number of stars. Summarize all the knowledge that had been accumulated by the 4th century. BC e., was able to the outstanding philosopher of the ancient world Aristotle (384-322 BC).

Rice. 1. Geocentric system of the world of Aristotle-Ptolemy.

His activities covered all natural sciences - information about the sky and Earth, about the patterns of movement of bodies, about animals and plants, etc. Aristotle's main merit as an encyclopedist scientist was the creation of a unified system of scientific knowledge. For almost two thousand years, his opinion on many issues was not questioned. According to Aristotle, everything heavy tends to the center of the Universe, where it accumulates and forms a spherical mass - the Earth. The planets are placed on special spheres that revolve around the Earth. Such a system of the world was called geocentric (from the Greek name for the Earth - Gaia). It was not by chance that Aristotle proposed to consider the Earth as the immovable center of the world. If the Earth moved, then, according to Aristotle’s fair opinion, a regular change in the relative positions of the stars on the celestial sphere would be noticeable. But none of the astronomers observed anything like this. Only at the beginning of the 19th century. The displacement of stars (parallax) resulting from the movement of the Earth around the Sun was finally discovered and measured. Many of Aristotle's generalizations were based on conclusions that could not be verified by experience at that time. Thus, he argued that the movement of a body cannot occur unless a force acts on it. As you know from your physics course, these ideas were refuted only in the 17th century. during the times of Galileo and Newton.

Heliocentric model of the Universe

Among ancient scientists, Aristarchus of Samos, who lived in the 3rd century, stands out for the boldness of his guesses. BC e. He was the first to determine the distance to the Moon and calculate the size of the Sun, which, according to his data, turned out to be more than 300 times larger than the Earth in volume. Probably, these data became one of the grounds for the conclusion that the Earth, along with other planets, moves around this largest body. Nowadays, Aristarchus of Samos has come to be called the “Copernicus of the ancient world.” This scientist introduced something new into the study of the stars. He believed that they were immeasurably further from the Earth than the Sun. For that era, this discovery was very important: from a cozy little home, the Universe was turning into an immense giant world. In this world, the Earth with its mountains and plains, with forests and fields, with seas and oceans became a tiny speck of dust, lost in a grandiose empty space. Unfortunately, the works of this remarkable scientist have practically not reached us, and for more than one and a half thousand years, humanity was sure that the Earth was the immovable center of the world. To a large extent, this was facilitated by the mathematical description of the visible movement of the luminaries, which was developed for the geocentric system of the world by one of the outstanding mathematicians of antiquity - Claudius Ptolemy in the 2nd century. AD The most difficult task was to explain the loop-like motion of the planets.

Ptolemy, in his famous work “Mathematical Treatise on Astronomy” (better known as “Almagest”) argued that each planet moves uniformly along an epicycle - a small circle, the center of which moves around the Earth along a deferent - a large circle. Thus, he was able to explain the special nature of the movement of the planets, which distinguished them from the Sun and Moon. The Ptolemaic system gave a purely kinematic description of the motion of the planets - the science of that time could not offer anything else. You have already seen that using a model of the celestial sphere to describe the movement of the Sun, Moon and stars allows you to carry out many calculations useful for practical purposes, although in reality such a sphere does not exist. The same is true for epicycles and deferents, on the basis of which the positions of the planets can be calculated with a certain degree of accuracy.

Rice. 2.

However, over time, the requirements for the accuracy of these calculations constantly increased, and more and more new epicycles had to be added for each planet. All this complicated the Ptolemaic system, making it unnecessarily cumbersome and inconvenient for practical calculations. Nevertheless, the geocentric system remained unshakable for about 1000 years. After all, after the heyday of ancient culture in Europe, a long period began during which not a single significant discovery was made in astronomy and many other sciences. Only during the Renaissance did a rise in the development of sciences begin, in which astronomy became one of the leaders. In 1543, a book by the outstanding Polish scientist Nicolaus Copernicus (1473-1543) was published, in which he substantiated a new - heliocentric - system of the world. Copernicus showed that the daily motion of all the stars can be explained by the rotation of the Earth around its axis, and the loop-like motion of the planets by the fact that all of them, including the Earth, revolve around the Sun.

The figure shows the movement of the Earth and Mars during the period when, as it seems to us, the planet is describing a loop in the sky. The creation of the heliocentric system marked a new stage in the development of not only astronomy, but also all natural science. A particularly important role was played by Copernicus’s idea that behind the visible picture of occurring phenomena, which seems true to us, we must look for and find the essence of these phenomena, inaccessible to direct observation. The heliocentric system of the world, substantiated but not proven by Copernicus, was confirmed and developed in the works of such outstanding scientists as Galileo Galilei and Johannes Kepler.

Galileo (1564-1642), one of the first to point a telescope at the sky, interpreted the discoveries made as evidence in favor of the Copernican theory. Having discovered the change of phases of Venus, he came to the conclusion that such a sequence can only be observed if it revolves around the Sun.

Rice. 3.

The four satellites of the planet Jupiter that he discovered also refuted the idea that the Earth is the only center in the world around which other bodies can rotate. Galileo not only saw mountains on the Moon, but even measured their height. Along with several other scientists, he also observed sunspots and noticed their movement across the solar disk. On this basis, he concluded that the Sun rotates and, therefore, has the kind of motion that Copernicus attributed to our planet. Thus, it was concluded that the Sun and Moon have a certain similarity with the Earth. Finally, observing many faint stars in and outside the Milky Way, inaccessible to the naked eye, Galileo concluded that the distances to the stars are different and that no “sphere of fixed stars” exists. All these discoveries became a new stage in understanding the position of the Earth in the Universe.

a > Heliocentric model of the solar system

Heliocentric system of the world: who developed it, when it arose, the role of Copernicus and adherents, description of the solar system, place of the planets and disputes with Ptolemy.

In the 16th-17th centuries. a scientific revolution took place. At this time, the foundations of everything were laid. For astronomy, the most significant figure was Nicolaus Copernicus, who developed the heliocentric model of the Universe.

He studied ancient developments and examined the movements of the planets. His conclusions were that the Sun is at the center of everything, and the Earth and other objects revolve around it. For us this is something familiar, but in those days for such heresy you could be locked up in prison.

However, Copernicus was not the first to think of this. But his heliocentric model of the world was the sum of all these ideas and solved complex problems. In addition, it described in detail the principles of the functioning of outer space.

Heliocentric model of the solar system and Ptolemaic model (geocentric)

The first to emerge was the geocentric model of the world, where our planet Earth was in the center, around which the rest of the celestial bodies revolved. It was actively developed by Ptolemy and Aristotle. It was based on visual observations. It seemed to ancient people that the Sun and other planets were flickering in our sky, which means they were moving relative to us.

In the 3rd century BC. scientists agreed that the Earth is a sphere, which means that everything else is made in the same shapes and rotates in a circle. Ptolemy also placed our Earth not just at the center of the system, but of the entire Universe.

We had to correct shortcomings in observations. Therefore, it was believed that all solar planets move in two spheres - deviations and epicycles. The first is a circle from the Earth, with which the length of the season was calculated. And the second is a wheel within a wheel to explain retrograde.

But this still did not save the situation, since the planets sometimes behaved completely unpredictably. Then Ptolemy created the equator - a geometric tool near the center of the planetary orbit, which forced it to move at a uniform angular speed.

This model was generally accepted, but too complex and sophisticated. But for 1,500 years it was used to create astronomical maps. In the 16th century it was changed to the Copernican heliocentric model.

Copernicus' heliocentric model of the solar system

In the 16th century, Nicolaus Copernicus began developing his model, drawing on the works of Aristarchus and Islamic scholars. In 1514, he distributed copies to a close circle of friends. The 40-page manuscript contained the main principles:

• Not all celestial bodies revolve around a single point;
• The earthly center is the center of the lunar sphere;
• All spheres rotate around the Sun, located near the universal center;
• The Earth-Sun distance is considered to be a small fraction of the distance between the Sun and other stars, so parallax is not visible;
• The stars don't move;
• The Earth orbits the Sun, resulting in the star's apparent seasonal migration;
• Earth's movement creates the appearance of retrograde movement of other planets;

Copernicus continued to collect information and in 1532 published his main work, “On the Revolutions of the Celestial Bodies.”

By placing the orbital paths of Mercury and Venus between us and the star, it was possible to explain the changes in their appearance. The retrograde movements of Mars and Jupiter also became clear. But the scientist knew that the church would react sharply to the new product, so the work was published only after his death (1542).

References in history

Copernicus was not the inventor of the new system. The first records belong to Aristarchus of Samos (310-230 BC), where the Sun was in the center.

He was even quoted by Archimedes, pointing out that the stars must be located much further away than we think. And this was the reason for the lack of parallax. Seleucus (190-150 BC) also wrote about heliocentrism, who even managed to prove this theory. He could calculate the geocentric constants and use them for the heliocentric. Or he observed the tides created by the Moon.

In the 5th century AD Martian Capella stated that Venus and Mercury must revolve around the Sun, then the inaccuracies in their appearance could be explained. Copernicus would later write that this scientist influenced his developments. Nicole Orest believed that our planet could have axial rotation.

The heliocentric model has also won supporters among Islamic scientists. Many of them became inspirations for Copernicus. Ptolemy was openly opposed by Abu Said al-Siizi in the 10th century. And in the 11th century, the treatise “Doubts in Ptolemy” by Alhazen was published.

From a philosophical point of view, Abu Rayhan Biruni was interested in axial rotation. Together with other astronomers, he discussed this possibility at the Ulugbeg Observatory. But things didn’t go further than talk.

The influence of the heliocentric model of the solar system

Copernicus's fears were in vain, because the church reacted weakly. Later they began to actively protest, but the theory had already gained influential supporters. Among them was Galileo Galilei, who discovered the moons of Jupiter. For his position, Galileo was put under house arrest.

Johannes Kepler developed elliptical orbits, which explained the rotation of planets with different accelerations. In addition, Copernicus' ideas became the impetus for a better understanding of physical laws, which led to gravity and inertia.