Almost everything educated people Our planet knows that it is round. There are, of course, figures who claim the opposite. Centuries-old studies also refute this issue, and photographs from Space, and travel reports. But for most, the spherical shape is an indisputable fact. Why is the Earth round? Under the influence of what forces did she acquire modern form?
History of discovery
Who proved that the Earth is round? Even ancient Greek and Roman thinkers spoke about the shape of the planet. Here are the names of the most authoritative scientists: Pythagoras, Theophrastus, Parmenides, Anaximander of Miletus (the teacher of Pythagoras). A couple of hundred years later, Aristotle brought experimental evidence this fact:
- All objects (having one center of gravity) fall at the same angle.
- When the Earth casts a shadow on the Moon (during lunar eclipses), this shadow has a rounded outline.
Another hundred years later, Eratosthenes calculated the radius of our planet and the length of its meridian. True, the units he used cannot be converted to modern ones. Therefore, it was not possible to verify the reliability of his calculations (or refute them).
Ferdinand Magellan made the first trip around the world. It was practical proof spherical shaped planet. After Copernicus wrote his work on the location heavenly bodies in Space. In particular, he said that the Earth revolves around the Sun and at the same time rotates around its axis. But the work of the Polish scientist was prohibited for religious reasons. Still the Middle Ages.
Next to his “comrades in the shop” was Newton. This is the first scientist who stated that our planet should be different from a ball. His followers managed to prove this fact. But still it is round. Not perfect, as the geometry suggests, but still...
Why did the planet acquire a round shape?
We need to remember that our planet was formed from liquid masses. And since she is a fairly massive and heavy body, the force of gravity optimally distributed internal and external pressure. That is, the entire surface has stabilized at equal distance from the center.
And also its own gravity. In conditions of weightlessness, it acts centripetally from the center of mass. All massive bodies, which are in Space, have a spherical shape. Look at a drop of rain. This too liquid body. In space, in weightlessness, it becomes spherical. True, it draws out the drop somewhat surface tension. But there is no weightlessness on Earth.
Our planet also became spherical due to its rotation. She spins non-stop around her axis. And at great speed. Have you seen how a glass blower works? If he needs to make a ball, he quickly spins a piece of liquid glass.
Under the influence of internal (planet composition) and external factors it turned out to be a “ball”. However, this influence also explains why the Earth’s topography is very diverse. Depressions and bulges prevent the planet from being a perfect sphere. She is a ball, but a conventional one, not a geometric one.
Due to rotation, the planet is somewhat flattened at the poles. Plus there are uneven surfaces. The result is a completely new and unique shape - the geoid. This term was coined by scientists to refer to the shape of the Earth.
If you ask any person what shape our planet has, he will answer without hesitation - a ball. Indeed, school textbooks initial course geography different authors, for example, N. A. Maksimova, O. V. Krylova and others position our planet as a ball or sphere. After all, even earthly shells are called spheres: lithosphere, hydrosphere, atmosphere, biosphere, geosphere. “A sphere is a closed surface, all points of which are equally distant from the center,” - this is the definition given by explanatory dictionary. Greek word“sphaira” means ball. Is this really true? Modern geodetic studies show that the shape of the Earth is complex: the surface of the ocean floor is, as it were, depressed, close to the center of the Earth, and the surface of the continents is the opposite. Therefore, our planet does not have the correct proportions.
So the problem of data inconsistency arises school textbook And scientific literature to describe the shape of the Earth. On the very first page of the geographical atlas there are two images of the Earth. One is a view from space, where we clearly see that the Earth is shaped like a ball; the other is the ancients’ idea of their place of residence, when people believed that the Earth was motionless and should have some kind of support. That's why ancient people- the Babylonians - thought that the Earth itself floated on the surface of the ocean, and the ancient Hindus, for example, believed that the Earth rested on four elephants standing on the back of a floating turtle.
Our ancestors imagined that the Earth rested on the backs of three large whales that floated on the surface of a huge ocean. Even in Ershov’s fairy tale “The Little Humpbacked Horse,” Ivanushka flies on a skate over a whale, on whose back there are villages, men ride on carts, rye is grown in the fields, and at the same time the whale swims in the sea-ocean.
The problem gets worse: so what shape is the Earth - flat, round, or some other?
Moreover, some peoples believed that it looked like a low stump of a cut tree, like flat surface which people live. Only in fairy tales can such huge whales or elephants exist that support our planet. It is known that all animals must eat and reproduce. In addition, not a single animal lives more than several hundred years; it ages and dies, not to mention the fact that no animal is able to withstand not only the weight of the entire Earth, but even a small mountain. And the Babylonians' idea that the Earth floats on the surface of the ocean, like a piece of wood, is also erroneous. After all, the Earth is very heavy for floating on water. Even if she could swim in some ocean, then the water of this ocean would also have to be supported by something.
The purpose of this work is to study the patterns of formation of the Earth's figure using practical physical experiment and theoretical scientific data.
During the work, the following tasks were solved:
1. Systematized theoretical material on developing views on true form Earth.
2. The shape of our planet was studied experimentally using physical instruments.
The tasks were solved using empirical and comparative analysis various data.
The relevance of this work lies in the fact that it contains an extensive systematization of knowledge on what would seem to be the simplest topic; interdisciplinary connections are widely shown - the integration of several subjects into each other: physics and geography, history and geography.
CHAPTER 1. EVIDENCE OF THE spherical shape of the earth.
People have long been interested in the question of the shape of the Earth. Origins of the idea of spherical shape The Earth is inextricably linked with the teachings of Pythagoras and his followers - the Pythagoreans: for the first time in the history of human thought, the idea of the spherical shape of the Earth and the symmetrically arranged spheres that make up the cosmos was logically consistently pursued.
Aristotle and his followers proved the sphericity of the Earth, which played a significant role in the formation of geography as a certain system of knowledge.
Eratosthenes considered the sphericity of the Earth, realizing that only scientific proof of the true shape of the planet could become the necessary foundation of geography. By the way, Eratosthenes first introduced the term “geography” instead of the previously used ones.
You can verify the convexity of the Earth by observing how they hide or appear tall objects on the line where the sky seems to converge with the earth’s surface, that is, on the horizon line. Hills, forests, mountains hide it from us. But at sea the horizon line is clearly visible. That's why sailors were the first to notice that the earth's surface is convex.
Approaching the shore, the sailors saw that at first only the tops of the mountains were visible, and as they approached them, the mountains seemed to grow before their eyes until their base became visible.
Moving away from the shore, the opposite was observed - the mountains seemed to sink into the sea: first their foot and structure on the shore disappeared from view, and then their peaks disappeared from view.
If the Earth were flat, mountains would not disappear from view, but would only become smaller as we move away from them. They could be seen hundreds of kilometers away with the same ease as we see ordinary houses hundreds of meters away. In reality, when the mountain disappears beyond the horizon, it cannot be seen even in the strongest spotting scope. But, if you climb to a high place, then the ship that has disappeared over the horizon can be seen again. Climbing on high places(they can even be the roofs of houses), you can notice that the horizon seems to be expanding.
Horizon expansion is one of the proofs of convexity earth's surface: If the Earth were flat, this phenomenon would not be observed.
The second proof of the convexity of the earth's surface is the appearance of new stars above the horizon when moving along the meridian. If you travel from Moscow to St. Petersburg, then in Tver the Polar Star will stand higher above the horizon than in Moscow, and in St. Petersburg even higher. This happens because Tver is almost 20 north of Moscow, and St. Petersburg is 40.
Such observations show that the earth's surface everywhere - on land and at sea - is convex, not flat.
The third proof of the sphericity of the Earth is the appearance of the Earth's shadow, which can be seen during the full moon, when the Earth is between the Sun and the Moon. Illuminated by the Sun, it casts a shadow into space, which can fall on the Moon. Then a total or partial lunar eclipse occurs: the earth’s shadow moves onto the bright disk full moon, and the edge of the earth's shadow is always round, the same as the shadow falling from an orange on the wall.
The fourth proof appeared in the era of the Great geographical discoveries, during the voyage of the Spanish navigator Ferdinand Magellan in 1519-1522. Sailing all the time to the west, he crossed the Atlantic Ocean, rounded South America through the strait named after him, and went out to Pacific Ocean. Sailing in one direction, the squadron crossed Indian Ocean and across the cape Good Hope entered the Atlantic, that is, a voyage around globe.
True, traveling around the world does not yet prove the sphericity of the Earth. If it had a shape similar to a zucchini or cucumber, it could also be driven around.
The fifth proof is the circular horizon line. If the Earth were not close in shape to a ball, then the horizon would not be in the shape of a perfect circle.
This proof allowed the German scientist Martin Beheim in the 15th century to build a model of the globe - a globe.
The sixth evidence - modern - is photographs of the Earth from space.
CHAPTER 2. THEORETICAL: THE TRUE SHAPE OF THE EARTH
However, a look from interplanetary stations And orbital satellites made it possible to confirm that our Earth is far from a perfect sphere.
This was first noticed in 1672 by the French astronomer Charles Richet. And they helped him with this. watch! Ordinary walkers with a pendulum. The scientist noticed that his watch, which was working properly in Paris, suddenly began to lag when moving to South America. At first, Richet assumed that the heat was to blame, because in Cayenne, located near the equator, it is much hotter than in Paris: “Under the influence of temperature, the metal expanded, the pendulum became longer, and so the clock began to lag,” the researcher reasoned. However, the calculation showed that the clock began to lag by 4 minutes! per day, as happened in practice, it is necessary that the difference in temperatures be. 2000!
The true cause of the paradox was explained only in 1787 by Isaac Newton. He reasoned that the reason for the clock lag was the rotation of the Earth around its axis (at the equator linear speed slightly higher than in Paris), as well as the oblateness of our planet at the poles. The rotation of the Earth on its axis causes it to flatten at the poles so that all points on the equator are 21 km further from the center than at the poles. Thus, the Earth is shaped like a tangerine, although it is much less compressed.
Newton's calculations were refined in the 18th century by the English scientist McLaurin. He proved that the Earth has the shape of a melon - a spheroid.
In 1834, quite complex calculations The German scientist Jacobi found that another name is more suitable for the shape of the Earth - a triaxial ellipsoid.
Further amendments complicated the picture: a certain “pear-shaped” appearance of the planet was noted.
The study of the shape of the Earth has shown that the Earth is compressed not only along the axis of rotation, but also in the plane of the equator, that is, in other words, the diameters of the equator are not the same length. This compression is minor, but it exists. But the Earth is not smooth, like a billiard ball. There are hills on it, mountain ranges, valleys, depressions of seas and oceans. Therefore, scientists take the ocean level as the earth's surface. The same level of the oceans can be mentally extended to the continents, if we cut through all the continents with such deep channels that all the oceans and seas would be connected to each other. The level in these channels was taken to be the Earth's surface. It is slightly different from the surface of a compressed ellipsoid.
This true form of the Earth was called GEOID (geo - Earth, id - form).
CHAPTER 3. PRACTICAL: THE TRUE SHAPE OF THE EARTH
The earth rotates around its axis. Experimentally, you can observe how the shape of a spherical body changes when rotating around its axis.
Experiment 1. Let's take a machine, which is an auxiliary device used to bring into rotational movement two flexible hoops connected to each other and secured by a vertical rod. The result is a model of a sphere, where the plates symbolize the meridians, and the connecting rod symbolizes the Earth’s axis. The upper attachment point can move freely along the rod. Let's install the device in a centrifugal machine and start rotating. We'll see the hoops start to flatten. And the faster we rotate the handle, the more flattened the “poles” become.
Experiment 2. So, the rotation of the Earth was reflected in its shape. Another experiment with a drop of vegetable oil swirled in a mixture of water and alcohol shows why this happens.
Pour a mixture of water and alcohol into a glass in such a proportion that vegetable oil neither floated up nor sank in it. Only then will the oil take the shape of a ball. Then carefully insert a light pinwheel on a thin rod into the oil ball. As the turntable rotates, the oil ball gradually begins to rotate, and the faster it rotates, the more it flattens along its axis.
Thus, the oblateness of the Earth is explained by its rotation. And the Earth committing full turn around its axis in 24 hours, as a rotating body has the shape of a spheroid, or ellipsoid of revolution, and not a sphere.
Other rotating celestial bodies are flattened in a similar way. Jupiter, for example, will be very flattened thanks to high speed rotation (one revolution per 10 hours). And the Moon, which makes one revolution around its axis in one month, is practically not flattened and has the shape of a ball.
CONCLUSION.
Thus, having studied the evidence of the spherical shape of the Earth, I came to the conclusion that the Earth, like all living things, has only its inherent shape, the change of which is influenced by various forces, including the speed of rotation around its axis and the Sun, the gravity of the Moon and other planets.
And there is no doubt that the Earth is a rotating ball. At the same time, it obeys the same movements as an ordinary top.
Therefore, we can say that the Earth is a giant top, changes in the speed of which did not go unnoticed in the formation of its shape.
Who said the earth is round? December 17th, 2014
They say that this is...
However, the hypothesis that our planet is spherical has existed for a very long time. The first to express this idea back in the 6th century BC was the ancient Greek philosopher and mathematician Pythagoras. Another philosopher, Aristotle, who lived in Ancient Greece two centuries later, brought visual evidence sphericity: after all, during lunar eclipses, the Earth casts a precisely round shadow on the Moon!
Gradually, the idea that the Earth is a ball hanging in space and not supported by anything spread more and more widely. Centuries have passed, people have long known that the Earth is not flat and does not rest on whales or elephants... We walked around the world, crossed our ball in literally all directions, flew around it on an airplane, photographed it from space. We even know why not only ours, but also all other planets, the Sun, the stars, the Moon, and others large satellites namely “round”, and not some other shape. After all, they are large and have enormous mass. Their own strength gravity - gravity - strives to give celestial bodies the shape of a ball.
Even if some force, greater than gravity, appeared, which would give the Earth the shape of, say, a suitcase, the end would still be the same: as soon as the action of this force ceased, the force of gravity would begin to collect the Earth again into a ball, “pulling in” protruding parts until all points on the surface are at an equal distance from the center.
Let's continue thinking about this topic...
Not a ball!
Back in the 17th century famous physicist and the mathematician Newton made a bold assumption that the Earth is not a ball at all, or rather, not quite a ball. He assumed it and proved it mathematically.
Newton “drilled” (mentally, of course!) two communicating channels to the center of the planet: one from the North Pole, the other from the equator, and “filled” them with water. Calculations showed that the water settled at different levels. After all, in a polar well, only the force of gravity acts on the water, but in an equatorial well, it also resists centrifugal force. The scientist argued: in order for both columns of water to exert equal pressure on the center of the Earth, that is, so that they have equal weight, the water level in the equatorial well should be higher - according to Newton’s calculations, by 1/230 of the average radius of the planet. In other words, the distance from the center to the equator is greater than to the pole.
To check Newton's calculations, the Paris Academy of Sciences sent two expeditions in 1735 - 1737: to Peru and Lapland. The expedition members had to measure meridian arcs - 1 degree each: one - in equatorial latitudes, in Peru, the other - in polar latitudes, in Lapland. After processing the expedition data, the head of the northern expedition, geodesist Pierre-Louis Maupertuis, announced that Newton was right: the Earth is compressed at the poles! This discovery of Maupertuis was immortalized by Voltaire in... an epigram:
Envoy of physics, brave sailor,
Having overcome both mountains and seas.
Dragging the quadrant among the snow and swamps,
Almost turning into a Lapp.
You found out after many losses.
What Newton knew without walking out the door.
It was in vain that Voltaire was so sarcastic: can science exist without experimental confirmation her theories?!
Be that as it may, now we know for sure that the Earth is flattened at the poles (if you like, stretched out at the equator). It is stretched, however, quite a bit: the polar radius is 6357 km, and the equatorial radius is 6378 km, only 21 km more.
Does it look like a pear?
However, is it possible to call the Earth, if not a ball, but an “oblate” ball, namely an ellipsoid of revolution? After all, as we know, its relief is uneven: there are mountains, there are also depressions. In addition, she is subject to the gravitational forces of others. celestial bodies, primarily the Sun and Moon. Even if their influence is small, the Moon is still capable of bending the shape of the liquid shell of the Earth - the World Ocean - by several meters, creating ebbs and flows. So - in different points The radii of “rotation” are different!
In addition, in the north there is a “liquid” ocean, and in the south there is a “solid” continent covered with ice - Antarctica. It turns out that the Earth has not entirely correct form, resembles a pear extended towards North Pole. And according to by and large its surface is so complex that it does not lend itself to strict mathematical description. Therefore, scientists have proposed a special name for the shape of the Earth - geoid. The geoid is an irregular stereometric figure. Its surface approximately coincides with the surface of the World Ocean and continues on the mainland. The same “height above sea level” that is indicated in atlases and dictionaries is measured precisely from this geoid surface.
Well, scientifically:
Geoid(from ancient Greek γῆ - Earth and other Greek εἶδος - view, literally “something like the Earth”) - a convex closed surface that coincides with the surface of water in the seas and oceans in a calm state and perpendicular to the direction of gravity at any point. Geometric body, deviating from the figure of rotation Ellipsoid of rotation and reflecting the properties of the gravity potential on the Earth (near the Earth’s surface), important concept in geodesy.
1. The world's oceans
2. Earth's ellipsoid
3. Plumb lines
4. Body of the Earth
5. Geoid
The geoid is defined as an equipotential surface earth's field gravity (level surface), approximately coinciding with the average water level of the World Ocean in an undisturbed state and conditionally continued under the continents. The difference between the actual mean sea level and the geoid can reach 1 m.
By definition equipotential surface, the surface of the geoid is perpendicular to the plumb line everywhere.
A geoid is not a geoid!
To be completely honest, it is worth admitting that due to the difference in temperature in different parts of the planet and the salinity of the oceans and seas, atmospheric pressure and other factors, the surface of the water surface does not coincide in shape even with the geoid, but has deviations. For example, at the latitude of the Panama Canal, the difference in levels between the Pacific and Atlantic Oceans is 62 cm.
The shape of the globe is affected by strong earthquakes. One of these magnitude 9 earthquakes occurred on December 26, 2004 in Southeast Asia, in Sumatra. University of Milan professors Roberto Sabadini and Giorgio Dalla Via believe that it left a “scar” on the planet’s gravitational field, causing the geoid to bend significantly. To test this assumption, the Europeans intend to send into orbit a new GOCE satellite, equipped with modern highly sensitive equipment. We hope that he will soon send us accurate information about what shape the Earth has today.
January 31st, 2014
Like a flat, worn-out coin
The planet rested on three whales.
And they burned smart scientists in the fires -
Those who insisted: “It’s not about the whales.”
N. Olev
By going outside and looking around, anyone can be convinced: the Earth is flat. There are, of course, hills and depressions, mountains and ravines. But overall it is clearly visible: flat, sloping at the edges. The ancients figured this out a long time ago. They saw the caravan disappearing over the horizon. Climbing the mountain, observers noticed that the horizon was expanding. This led to the inevitable conclusion: the surface of the Earth is a hemisphere. In Thales, the Earth floats like a piece of wood in an endless ocean.
When did these ideas change? In the 19th century, a false thesis was established, which is still being replicated, that people considered the Earth to be flat before the great geographical discoveries.
Thus, the manual for teachers “Lessons on the world around us” of 2007 says: “For a long time, ancient people considered the Earth to be flat, lying on three whales or three elephants and covered by the dome of the sky... Scientists who put forward a hypothesis about the spherical shape of the Earth were laughed at, they persecuted the church. The navigator Christopher Columbus was the first to believe in this hypothesis... The teacher can tell the children that the first person who saw with his own eyes that the Earth is not flat was cosmonaut Yuri Gagarin.”
In fact, already in the 3rd century BC. the ancient Greek scientist Eratosthenes of Cyrene (c. 276-194 BC) not only firmly knew that the Earth is a sphere, but also managed to measure the radius of the Earth, obtaining a value of 6311 km - with an error of no more than 1 percent!
Around 250 BC, Greek scientist Eratosthenes for the first time measured the globe quite accurately. Eratosthenes lived in Egypt in the city of Alexandria. He guessed to compare the height of the Sun (or its angular distance from a point above your head, zenith, which is called - zenith distance) at the same point in time in two cities - Alexandria (in northern Egypt) and Siena (now Aswan, in southern Egypt). Eratosthenes knew that on the day summer solstice(June 22) Sun in noon illuminates the bottom deep wells. Therefore, at this time the Sun is at its zenith. But in Alexandria at this moment the Sun is not at its zenith, but is 7.2° away from it.
Eratosthenes obtained this result by changing the zenith distance of the Sun using his simple goniometric instrument - the scaphis. This is simply a vertical pole - a gnomon, fixed at the bottom of a bowl (hemisphere). The skafis is installed so that the gnomon takes a strictly vertical position (directed to the zenith). A pole illuminated by the sun casts a shadow divided into degrees inner surface skafisa.
So at noon on June 22 in Siena the gnomon does not cast a shadow (the Sun is at its zenith, its zenith distance is 0°), and in Alexandria the shadow from the gnomon, as can be seen on the scaphis scale, marked a division of 7.2°. In the time of Eratosthenes, the distance from Alexandria to Syene was considered to be 5,000 Greek stadia (approximately 800 km). Knowing all this, Eratosthenes compared an arc of 7.2° with the entire circle of 360° degrees, and a distance of 5000 stadia with the entire circumference of the globe (let's denote it by the letter X) in kilometers. Then from the proportion it turned out that X = 250,000 stadia, or approximately 40,000 km (imagine, this is true!).
If you know that the circumference of a circle is 2πR, where R is the radius of the circle (and π ~ 3.14), knowing the circumference of the globe, it is easy to find its radius (R):
It is remarkable that Eratosthenes was able to measure the Earth very accurately (after all, today it is believed that average radius Earth 6371 km!).
And a hundred years before him, Aristotle (384-322 BC) gave three classical proofs of the sphericity of the Earth.
Firstly, when lunar eclipses the edge of the shadow cast by the Earth on the Moon is always an arc of a circle, and the only body capable of giving such a shadow at any position and direction of the light source is a ball.
Secondly, ships, moving away from the observer into the sea, are not gradually lost from sight due to long distance, and almost instantly they seem to “drown”, disappearing beyond the horizon.
And thirdly, some stars can only be seen from certain parts Earth, but they are never visible to other observers.
But Aristotle was not the discoverer of the sphericity of the Earth, but only provided irrefutable evidence of a fact that was known to Pythagoras of Samos (c. 560-480 BC). Pythagoras himself may have relied on the evidence not of a scientist, but of a simple sailor Skilacus of Cariande, who in 515 BC. made a description of his voyages in the Mediterranean.
What about the church?
There was a decision to condemn heliocentric system, approved in 1616 by Pope Paul V. But the persecution of supporters of the sphericity of the Earth in Christian churches there wasn't. The fact that “before” the church imagined the Earth standing on whales or elephants was invented in the 19th century.
By the way, why was Giordano Bruno really burned?
And yet the church made its mark on the issue of the shape of the Earth.
Of the 265 people who set off on September 20, 1519 on a trip around the world under the leadership of Magellan, only 18 sailors returned on September 6, 1522 on the last of the ships, sick and exhausted. Instead of honors, the team received public repentance for one lost day as a result of moving through time zones around the Earth in westward. So the Catholic Church punished the heroic team for a mistake in celebrating church dates.
This paradox world travels for a long time was not recognized in society. In Jules Verne's novel Around the World in 80 Days, Phileas Fogg almost lost his entire fortune due to ignorance. “Science and Life” of the 80s describes conflicts between teams returning from a “round the world” trip with accounting departments who do not want to pay for an extra day of business travel.
Misconceptions and primitive ideas persist not only in the church.
It’s probably worth noting one more point, the fact is that the shape of the Earth is different from a ball.
Scientists began to guess about this back in the 18th century, but it was difficult to find out what the Earth really was like - whether it was compressed at the poles or at the equator. To figure this out, French Academy Sciences had to equip two expeditions. In 1735, one of them went to carry out astronomical and geodetic work in Peru and did this in the equatorial region of the Earth for about 10 years, and the other, Lapland, worked in 1736–1737 near the Northern Arctic Circle. As a result, it turned out that the arc length of one degree of the meridian is not the same at the Earth's poles and at its equator. The meridian degree turned out to be longer at the equator than at high latitudes (111.9 km and 110.6 km). This can only happen if the Earth is compressed at the poles and is not a ball, but a body similar in shape to spheroid. At the spheroid polar radius is smaller equatorial(the polar radius of the earth's spheroid is almost shorter than the equatorial radius 21 km).
It's good to know that great Isaac Newton (1643–1727) anticipated the results of the expeditions: he correctly concluded that the Earth is compressed, which is why our planet rotates around its axis. In general, the faster a planet rotates, the greater its compression should be. Therefore, for example, the compression of Jupiter is greater than that of the Earth (Jupiter manages to rotate around its axis in relation to the stars in 9 hours 50 minutes, and the Earth only in 23 hours 56 minutes).
And one more thing. The true figure of the Earth is very complex and differs not only from a sphere, but also from a spheroid rotation. True, in in this case we're talking about about the difference not in kilometers, but... meters! Scientists are still engaged in such a thorough clarification of the figure of the Earth, using for this purpose specially conducted observations with artificial satellites Earth. So it is quite possible that someday you will have to take part in solving the problem that Eratosthenes took on a long time ago. This is very what people need case.
What is the best figure for you to remember on our planet? I think that for now it is enough if you imagine the Earth in the form of a ball with an “additional belt” put on it, a kind of “splash” on the equator region. Such a distortion of the Earth’s figure, turning it from a sphere into a spheroid, has considerable consequences. In particular, due to the attraction of the “additional belt” by the Moon, the earth’s axis describes a cone in space in about 26,000 years. This is the movement earth's axis called precessional. As a result, the role North Star, which now belongs to α Ursa Minor, alternately played by some other stars (in the future it will become, for example, α Lyrae - Vega). Moreover, due to this ( precessional) movement of the earth's axis signs of the zodiac more and more do not coincide with the corresponding constellations. In other words, 2000 years after the Ptolemaic era, the “sign of Cancer,” for example, no longer coincides with the “constellation Cancer,” etc. However, modern astrologers try not to pay attention to this...
Where did this stupid idea of a flat Earth with three elephants/whales come from?
Nprime Thales believed that the Earth floats in water, like a piece of wood. Anaximander imagined the Earth in the form of a cylinder (and indicated that its diameter was exactly three times more height), on the upper end of which people live. Anaximenes believed that the Sun and Moon are as flat as the Earth, but corrected Anaximander, pointing out that the Earth, although flat, is not round in plan, but rectangular, and does not float in water, but is supported by compressed air. Hecataeus, based on the ideas of Anaximander, compiled geographical map. Anaxagoras and Empedocles did not object to this to the founders, considering such ideas not to contradict physical laws. Leucippus, considering the Earth to be flat, and the atoms falling perpendicular to this plane in one direction, could not understand how then the atoms could connect with each other, forming bodies - and said that no, the atoms in their fall must somehow deviate at least a little. Democritus in defense flat earth gave the following argument: if the Earth were a ball, then the sun, setting and rising, would intersect the horizon in an arc of a circle, and not in a straight line, as in reality. Epicurus solved the problem of the fall of atoms onto a flat Earth, which tormented Leucippus, by attributing to the atoms free will, by virtue of which they deviate and unite at will.
Obviously, these ancient Greek atheist-materialist scientists relied on the mythological ideas set forth by poetic language by Homer and Hesiod in the 7th-8th centuries BC. The Hindus, Sumerians, Egyptians, and Scandinavians had similar myths about a flat Earth. But I don’t want to go even further there - I’m writing about something completely different. As a curiosity, one can note the book “Christian Topography” by Cosmas Indicopleus, written between 535 and 547, in which the author presents the Earth as a flat rectangle covered with a convex roof of the sky - a sort of chest-chest. This book was immediately criticized by Cosmas’ contemporary John the Grammar (c. 490-570), who then cited the same quotations from the Bible as I did as a justification for the sphericity of the Earth. The official Church did not interfere in this dispute about the shape of the Earth; it was much more worried about the heretical views of the disputants - Cosmas was a Nestorian, and John was a tritheist and Monophysite. Basil the Great disapproved of such disputes, considering their very subject not related to issues of faith.
If you start looking for elephants/whales, then first of all you can turn to the once popular work of Slavic folk-spiritual literature - “The Book of the Pigeon”, where there is a verse: “The earth is founded on seven pillars.” Folk legend about the Book of Doves goes back to the “book with seven seals” in the 5th chapter of the Revelation of John the Theologian, and the verse about whales is borrowed from the apocrypha “Conversation of the Three Hierarchs”. The outstanding collector of Slavic folklore A.N. Afanasyev wrote: “There is a legend among our common people that the world stands on the back of a colossal whale, and when this monster, suppressed by the weight earth's circle, wags its tail, then there is an earthquake. Others claim that from time immemorial four whales served as support for the earth, that one of them died, and his death was the cause global flood and other revolutions in the universe; when the other three also die, at that time the end of the world will come. An earthquake occurs because whales, having laid on their sides, turn to the other side. They also say that in the beginning there were seven whales; but when the earth became heavy with human sins, the four went into the Ethiopian abyss, and in the days of Noah, all of them went there. And so there was a general flood." Some linguists suspect that in fact, sea animals have nothing to do with it, but we are talking about fixing the Earth at its four edges, since in the ancient Slavic language the root “whale” meant “edge”. In this case, we again return to Kosma Indikoplov, whose curious book about the rectangular Earth was very popular in Rus' among the common people.
"Flat Earth Society"
Well, in order to finally amuse the tired reader, I will point out such a curiosity, but complete insanity, as the existence in our enlightened times of the “Flat Earth Society”. However, the Flat Earth Society existed from 1956 to beginning of XXI centuries and counted in its better times up to 3,000 members. They considered photographs of the Earth from space to be fakes, and other facts – a conspiracy of authorities and scientists.
The origins of the Flat Earth Society were English inventor Samuel Rowbotham (1816-1884), who argued that the Earth was flat in the 19th century. His followers founded the Universal Zetetic Society. In the USA, Rowbotham's ideas were adopted by John Alexander Dowie, who founded the Christian Catholic Church in 1895. apostolic church. In 1906, Dowie's deputy, Wilbur Glenn Voliva, became head of the church and advocated for a flat earth until his death in 1942. In 1956, Samuel Shenton revived the World Zetetic Society under the name International Flat Earth Society. He was succeeded as president of the society in 1971 by Charles Johnson. Over the three decades of Johnson's presidency, the society's number of supporters increased significantly, from a few members to approximately 3,000 people from different countries. The society distributed newsletters, leaflets, etc. similar literature, which advocated the flat Earth model. Represented by its leaders, the society argued that the landing of man on the moon was a hoax, filmed in Hollywood from a script by Arthur C. Clarke or Stanley Kubrick. Charles Johnson died in 2001, and present moment The continued existence of the International Flat Earth Society is in doubt. According to supporters of the society, all governments on Earth have entered into a global conspiracy to deceive people. When Samuel Shenton was shown photographs of the Earth from orbit and asked what he thought of them, he replied: “It is easy to see how photographs of this sort can fool an ignorant person.”
