Why is the earth round for kids. Why does the Earth have a rounded shape? Our planet is round because

The sun, stars, earth, moon, all the planets and their large satellites are "round" (spherical) because they have a very large mass. Their own force of gravity (gravity) tends to give them the shape of a ball.

If some force gives the Earth the shape of a suitcase, then at the end of its action, the force of gravity will again begin to collect it into a ball, "pulling" the protruding parts until its entire surface is established (i.e. stabilized) at an equal distance from the center.

Why the suitcase does not take the form of a ball

In order for a body to become spherical under the action of its own gravitational force, this force must be large enough, and the body must be plastic enough. It is desirable - liquid or gaseous, since gases and liquids most easily acquire the shape of a ball when a large mass is accumulated and, as a result, gravity. The planets, by the way, are liquid inside: under a thin layer of solid crust they have liquid magma, which even sometimes pours out onto their surface - during volcanic eruptions.

All stars and planets have a spherical shape from birth (formation) and throughout their existence - they are quite massive and plastic. For smaller bodies - for example, asteroids - this is not the case. First, their mass is much less. Secondly, they are completely solid. If, for example, the asteroid Eros had the mass of the Earth, it would also be round.

The earth is not quite a sphere

First, the Earth rotates around its axis, and at a fairly high speed. Any point on the earth's equator moves at the speed of a supersonic aircraft (see the answer to the question "Can you outrun the sun?"). The farther from the poles, the greater the centrifugal force that opposes the force of gravity. Therefore, the Earth is flattened at the poles (or, if you like, stretched at the equator). It is flattened, however, quite a bit, about one three hundredth: the equatorial radius of the Earth is 6378 km, and the polar one is 6357 km, only 19 kilometers less.

Secondly, the surface of the earth is uneven, it has mountains and depressions. Still, the earth's crust is solid and retains its shape (more precisely, it changes it very slowly). True, the height of even the highest mountains (8-9 km) is small compared to the radius of the Earth - a little more than one thousandth.

For more information about the shape and size of the Earth, see (you will learn what geoid, ellipsoid of revolution and Krasovsky ellipsoid).

Thirdly, the earth is affected by gravitational forces from other celestial bodies - for example, the Sun and the Moon. True, their influence is very small. And yet, the gravitational force of the Moon is capable of slightly (by several meters) distorting the shape of the liquid shell of the Earth - the World Ocean - creating ebbs and flows.

The shape of the Earth - our home - worried humanity for a long time. Today, every student has no doubt that the planet is spherical. But it took a long time to get to this knowledge, they went through church anathemas and the courts of the Inquisition. Today people are wondering who proved that the Earth is round. After all, not everyone liked the lessons of history and geography. Let's try to find the answer to this interesting question.

Excursion into history

Many scientific works confirm us in our thoughts that before the famous Christopher Columbus, mankind believed that they lived on a flat Earth. However, this hypothesis does not stand up to scrutiny for two reasons.

1. discovered a new continent, and did not sail to Asia. If he had anchored off the coast of real India, then he could be called the man who proved the sphericity of the planet. The discovery of the New World is not a confirmation of the round shape of the Earth.
2. Long before the epochal journey of Columbus, there were people who doubted that the planet was flat, and presented their arguments as evidence. It is likely that the navigator was familiar with the works of some ancient authors, and the knowledge of the ancient sages was not lost.

Is the earth round?

Different peoples had their own ideas about the structure of the world and space. Before answering the question of who proved that the Earth is round, you should familiarize yourself with other versions. The earliest theories of world-building claimed that the earth was flat (as it was seen by people). They explained the movement of heavenly bodies (sun, moon, stars) by the fact that it was their planet that was the center of the Cosmos and the Universe.

In ancient Egypt, the Earth was represented by a disk lying on four elephants. They, in turn, stood on a giant turtle floating in the sea. The one who discovered that the Earth is round has not yet been born, but the theory of the sages of the pharaoh could explain the causes of earthquakes and floods, the rising and setting of the sun.

The Greeks also had their own ideas about the world. The earthly disk in their understanding was covered with celestial spheres, to which stars were tied with invisible threads. They considered the moon and the sun to be gods - Selena and Helios. Nevertheless, in the books of Pannekoek and Dreyer, the works of the ancient Greek sages are collected, which contradicted the then generally accepted views. Eratosthenes and Aristotle were the ones who discovered that the earth is round.

The Arab teachings were also famous for their precise knowledge of astronomy. The tables of the movement of stars they created are so accurate that they even raised doubts about their authenticity. The Arabs, with their observations, pushed society to change their ideas about the structure of the world and the universe.

Evidence for the sphericity of celestial bodies

I wonder what guided the scientists, denying the observations of the people around them? The one who proved that the Earth is round drew attention to the fact that if it were flat, then the luminaries would be visible in the sky at the same time for everyone. But in practice, everyone knew that many of the stars that are visible in the Nile Valley cannot be seen over Athens. The sunny day in the Greek capital is longer than, for example, in Alexandria (this is due to the curvature in the north-south and east-west directions).

The scientist, who proved that the Earth is round, noticed that the object, moving away during movement, leaves only its upper part visible (for example, the masts of the ship are visible on the shore, and not its hull). This is only logical if the planet is spherical and not flat. And Plato also considered the fact that the ball is an ideal shape to be a strong argument in favor of sphericity.

Modern evidence for nodularity

Today we have technical devices that allow us not only to observe celestial bodies, but also to rise into the sky and see our planet from the side. Here is some more evidence that it is not flat. As you know, during the blue planet closes the night luminary itself. And the shadow is round. And also the various masses that make up the Earth tend to go down, giving it a spherical shape.

Science and Church

The Vatican recognized that the Earth is round rather late. When it was impossible to deny the obvious. Early European writers at first dismissed this theory as contradicting Scripture. During the spread of Christianity, not only other religions and pagan cults succumbed to persecution. All scientists who conducted various experiments, made observations, but did not believe in one God, were considered heretics. At that time, manuscripts and entire libraries were destroyed, temples and statues, objects of art were destroyed. The holy fathers believed that people do not need science, only Jesus Christ is the source of the greatest wisdom, and there is enough information in the holy books for life. The geocentric theory of the structure of the world was also considered incorrect and dangerous by the church.

Cosmas Indikopleust described the Earth as a kind of box, at the bottom of which rested a stronghold inhabited by people. The sky served as a "lid", but it was motionless. The moon, stars and sun moved like angels across the sky and hid behind a high mountain. Above this complex structure rested the Kingdom of Heaven.

Some unknown geographer from Ravenna described our planet as a flat object, surrounded by an ocean, an endless desert and mountains, behind which the sun, moon and stars are hiding. Isidore (bishop of Seville) in 600 AD did not exclude the spherical shape of the Earth in his works. Bede the Venerable was based on the work of Pliny, therefore he stated that the Sun is larger than the Earth, that they are spherical, and that the cosmos is not geocentric.

Summing up

So, returning to Columbus, it can be argued that his path was not based solely on intuition. Not wanting to diminish his merits, we can say that the knowledge of his era should have brought him to India. And society no longer rejected the spherical shape of our house.

The first idea about the Earth-sphere was expressed by the Greek philosopher Eratosthenes, who measured the radius of the planet already in the fourth century BC. The error of his calculations was only one percent! Checked his guesses in the sixteenth century, having made his famous Who proved that the Earth is round? Theoretically, this was done by Galileo Galilei, who, by the way, was sure that it was she who revolves around the sun, and not vice versa.

Little whys often ask parents a lot of questions that interest them. And adults themselves will be interested to know, for example, why the earth is round and revolves around the sun. Even Galileo explained why the earth revolves around its axis, as well as around the sun. Learn about it right now!

How the earth, moon and sun rotate

For many years, mankind has been looking for answers to questions - why does the Earth rotate, why does the earth rotate around the sun, how do scientists explain these phenomena? The well-known phrase of Galileo only complicated the task of astronomers who are trying to convey to each of us in simple words the features of the nature of rotation. And children and adults are always curious to know why the moon revolves around the earth, and is it true that our planet has the shape of a ball?

There are many assumptions that want to convey to mankind the essence of the phenomenon of rotation and the fact why the earth is round for children.

1. According to the first theory, our planet began to rotate at the beginning of its appearance, and by inertia (out of habit) it is still spinning. Because of this, the days become either shorter or longer.
2. Just as it is impossible to connect two magnets with equally charged fields, so our planet, due to the same poles, moves all the time and keeps at some distance from the Sun.
3. According to another version, the Sun heats our home planet so much that it makes it move.

But there is no consensus among scientists why the Earth is spinning today.

Why is our planet round?

Of course, parents themselves try to answer the questions that arise in their rapidly growing children. But sometimes questions on the topic “The Earth is round, why don’t we fall?” capable of confusing any adult. The sun, moon, earth and other satellites are spherical. For those who are wondering why the earth is round, Wikipedia and other sources will always find interesting answers. Since all large satellites have a large mass, their gravitational force wants to give these luminaries the shape of a ball. Of course, our planet is not quite round, it is, as it were, flattened from the poles, in addition, there are depressions and mountains on its surface.

All the curious will be able to learn more about all this and much more by looking at why the earth is round, a video from Youtube below.

And then a lot of things for you and your children will cease to be a mystery. Read My Tips, learn for yourself and share with friends)))

Have you ever wondered why is the earth round? Why is the Earth not flat, as previously thought, or, say, not square...? Why a ball? And finally, what gave our planet a spherical shape?

You need to start with the fact that the ball is not at all a rare form, on the contrary, the ball is almost the most common form of objects in Universe. All stars, planets, planetary satellites, large asteroids are round, or rather spherical. One of the fundamental forces acting in the Universe is to blame for this - gravity.

The force of gravity.

Gravity is a very interesting force. It dominates the macrocosm, controlling the movements of planets, stars and even entire galaxies, but is almost completely absent in the microcosm, and has no effect on micro-objects, such as atoms. This is explained by the fact that the force of attraction (gravity) directly depends on the mass of the object, the greater the mass, the greater the force, and vice versa.

It is thanks to the force of gravity that all large objects in the universe have ball shape, since their attractive force is so great that it sort of pulls in and / or pushes out individual parts of the body until the entire surface is set at the same distance from the center. Moreover, this force is constant and acts throughout the entire existence of the object, in other words, if the Earth, for some incredible reason, acquires any other shape other than a ball, for example, a cube, the gravitational force will eventually again give the Earth a spherical shape.

Why aren't all objects round?

If you carefully read the two previous paragraphs, you should learn that only those objects that have a very large mass and, accordingly, gravitational force, become round (spherical). But there is another nuance here. Astronomers know a large number of huge asteroids and dwarf planets that have sufficient mass, but for some reason have a spherical shape. This can be explained quite simply, unlike stars and planets, asteroids consist entirely of stone and / or metal (stars and planets are almost completely composed of liquid matter: molten metals, gases ..., and only in rare cases the planets are covered with thin solid matter ). For this reason, it is much more difficult for the force of gravity to change the shape of a solid object, but even in this case, gravity will tend to give the body a round shape, only it will take much more time.

The earth is not exactly round.

Well, this is no longer a secret: the Earth is not a perfect ball! The shape of the Earth is more like an ellipse slightly flattened at the poles, in the scientific world this "figure" is called geocide. In addition, individual parts of the Earth's surface rise or are depressed against the background of the general level. The reason for this is also gravity, but not the Earth, but its nearest neighbor - Moon. The moon constantly revolves around our planet and also constantly attracts the earth's surface to itself, causing ebbs and flows on the sea, and uneven terrain on land.

OBJECTS FALL STRAIGHT DOWN WITHOUT OFFSET

If the earth below us really rotated in an easterly direction, as the heliocentric model suggests, then vertically fired cannon balls should fall noticeably to the west. In fact, whenever this experiment was carried out, cannonballs fired perfectly vertically from a plumb line, illuminated by a fuse, reached the top in an average of 14 seconds and fell back within 14 seconds by no more than 2 feet (0.6 m) from the cannon, or sometimes straight back into the muzzle! If the Earth actually rotated at 600-700 miles per hour (965-1120 km/h) in the mid-latitudes of England and America, where the experiments were carried out, cannonballs should fall as much as 8400 feet (2.6 km) or so. miles and a half behind the cannon!

AIRCRAFT FLY EQUALLY IN ALL DIRECTIONS AND WITHOUT CORRECTION FOR THE CURVATURE AND ROTATION OF THE EARTH

If the Earth beneath our feet were spinning at several hundred miles per hour, then helicopter and hot air balloon pilots would simply have to fly straight up, hover, and wait for their destination to reach them! This has never happened in the history of aeronautics.

For example, if the Earth and its lower atmosphere were to rotate together in an eastward direction at 1,038 miles per hour (1,670 km/h) at the equator, then airplane pilots would have to accelerate an additional 1,038 miles per hour when flying west! And pilots heading north and south need to set diagonal courses to compensate! But since no compensation is required, except for the fantasies of astronomers, it follows that the Earth is motionless.

CLOUDS AND WIND MOVING WHEN THE EARTH ROTATES HIGHLY

If the Earth and atmosphere are constantly spinning eastward at 1,000 miles per hour, how can clouds, wind, and weather randomly and unpredictably go in different directions, often heading in opposite directions at the same time? Why can we feel a slight westerly breeze, but not the incredible supposed eastward spin of the Earth at 1,000 miles per hour!? And how is this magic Velcro-gravity strong enough to pull alone miles of the earth's atmosphere, yet so weak that it allows little bugs, birds, clouds, and planes to move freely at the same pace in any direction?

THE WATER IS EVERYWHERE, DESPITE THE CURVATURE OF THE EARTH

If we lived on a rotating spherical Earth, then every pond, lake, swamp, canal and other places with stagnant water would have a small arc or semicircle, expanding from the center downwards.

In Cambridge, England, there is a 20 mile canal called "Old Bedford" running in a straight line through the Fenlands, known as Bedford Plain. Water is not interrupted by gates and sluices and remains stationary, which makes it ideal for determining the reality of the existence of curvature. In the second half of the 19th century, Dr. Samuel Rowbotham, the famous "flat earther" and author of the wonderful book "The Earth is not a ball! Experimental study of the true shape of the Earth: proof that it is a plane, without axial or orbital motion; and only the material world in the universe!” went to Bedford Plain and conducted a series of experiments to determine whether the surface of standing water was flat or convex.
On the 6 mile (9.6 km) surface, no descent or downward bend was seen from line of sight. But if the earth is a sphere, then the surface of the water, 6 miles long, must be 6 feet higher at the center than at its ends. From this experiment it follows that the surface of still water is not convex and therefore the Earth is not a sphere!

WATER DOES NOT SPOUT DUE TO THE GREAT ROTATION OF THE EARTH AND CENTRIFUGAL FORCE
“If the Earth were a ball, rotating and dashingly flying in “space” at a speed of “one hundred miles in 5 seconds”, then the waters of the seas and oceans could not, by any laws, stay on the surface. To claim that they could be held under these circumstances is an outrage to human understanding and trust! But if the Earth - which is a habitable landmass - were to be recognized as "protruding from the water and standing in the water" from the "great depth" that is surrounded by a boundary of ice, we can throw that claim back into the teeth of those who made it and wave before them is the flag of reason and common sense, with the proof signed on it that the earth is not a sphere." - William Carpenter

THE LONGEST RIVERS IN THE WORLD DON'T HAVE WATER LEVEL VARIATIONS DUE TO THE EARTH'S CURVATURE

In one part of its long course, the great river Nile flows for a thousand miles at a fall of only 1 foot (30 cm). This feat would be completely impossible if the Earth had a spherical curve. Many other rivers, including the Congo in West Africa, the Amazon in South America, and the Mississippi in North America, all travel thousands of miles in directions totally inconsistent with the supposed sphericity of the Earth.

RIVERS FLOW IN ALL DIRECTIONS, NOT BOTTOM UP

“There are rivers that flow east, west, north and south, that is, rivers flow in all directions on the surface of the Earth at the same time. If the Earth were a ball, then some would flow uphill and others down, referring to what "up" and "down" really means in nature, no matter what form they take. But since rivers do not flow uphill, and the theory of the sphericity of the earth requires it, this proves that the Earth is not a ball.

ALWAYS EQUAL HORIZON

Whether it's sea level, the summit of Mount Everest, or flying hundreds of thousands of feet in the air, always the horizontal line of the horizon rises to the level of the observer's eyes and remains perfectly straight. You can test yourself on the beach or hilltop, in a large field or desert, aboard a hot air balloon or helicopter; you will see the panoramic horizon rise with you and remain absolutely horizontal everywhere. If the Earth were really a big ball, the horizon would have to drop as you ascend, not rise to the level of your eyes, but move away from each end of the periphery of your vision, not remain flat along its entire length.

If the Earth were really a large ball 25,000 miles (40,233 km) in circumference, then the horizon would be noticeably curved even at sea level, and anything on or approaching the horizon would appear slightly tilted from our perspective. Distant buildings along the skyline would look like the Leaning Tower of Pisa falling away from the observer. A balloon, rising and then gradually receding from you, on a spherical earth would seem to slowly and steadily lean back more and more along with its receding; the bottom of the basket gradually comes into view, while the top of the balloon disappears from view. In reality, however, buildings, balloons, trees, people, anything and everything remains at the same angle relative to the surface or horizon, no matter how far away the observer is.

“Wide areas show an absolutely flat surface, from the Carpathians to the Urals at a distance of 1500 (2414 km) miles there is only a slight rise. South of the Baltic, the country is so flat that the prevailing northerly wind will drive water from the Szczecin Bay into the mouth of the Odra, and reverse the river for 30 or 40 miles (48-64 km). The plains of Venezuela and New Granada in South America, located on the left side of the Orinoco River, are called Llanos or flat fields. Often, at a distance of 270 square miles (700 sq. km), the surface does not change a single foot. The Amazon only descends 12 feet (3.5m) in the last 700 miles (1126km) of its course; La Plata descends only one thirty-third of an inch per mile (0.08 cm / 1.6 km) ”, - Rev. T. Milner, "Atlas of Physical Geography"

The lighthouse in Port Nicholson, New Zealand, is 420 feet (128m) above sea level and is visible 35 miles (56km), but that means it must be 220 feet (67m) below the horizon. The Jogero Lighthouse in Norway is 154 feet (47m) above sea level and is visible at a distance of 28 statute miles (46km), which means it must be 230 feet below the horizon. The lighthouse at Madras, on the Esplanade, is 132 feet (40m) high and is visible from 28 miles (46km) when it should be 250 feet (76m) below line of sight. The 207-foot (63m) Cordonin lighthouse on the west coast of 47 France is visible from 31 miles (50km), which should be 280 feet (85m) below line of sight. The lighthouse at Cape Bonavista, Newfoundland is 150 feet (46m) above sea level and is visible from 35 miles (56km) when it should be 491 feet (150m) below the horizon. The height of the lighthouse - the spire of the church of St. Botolph in Boston is 290 feet (88m), it is visible from a distance of more than 40 miles (64km), when it should be hidden as much as 800 feet (244m) below the horizon!

CANALS, RAILWAYS ARE DESIGNED WITHOUT CONSIDERATION OF THE CURVATURE OF THE EARTH

Surveyors, engineers, and architects never take into account the supposed curvature of the Earth in their designs, which is further evidence that the world is a plane, not a planet. Canals and railroads, for example, are always laid horizontally, often hundreds of miles, without regard for any curvature.
Engineer W. Winkler in his "Review of the Earth" of October 1893 wrote about the alleged curvature of the Earth: "As an engineer with 52 years of experience, I saw that this absurd assumption is used only in school textbooks. Not a single engineer even thinks of taking into attention to this kind of thing. I have designed many miles of railroads and even more canals, and it never even occurred to me to allow for curvature of the surface, much less take it into account. Accounting for curvature means - 8 inches on the first mile of the canal, then an increase in accordance with the figure square of the distance in miles, so a small shipping channel, say 30 miles long, would have, by the above rule, a curvature offset of 600 feet (183m) Think about it, and please trust that the engineers not so stupid. Nothing like that counts. We don't think about taking into account a curvature of 600 feet for a railroad or canal line 30 miles (965 km) long, more than we spend our time trying to embrace the immensity."

AIRCRAFT FLY ONLY AT EQUAL HEIGHTS, WITHOUT CORRECTION FOR THE CURVATURE OF THE EARTH

If the Earth were a sphere, then airplane pilots would have to constantly adjust their altitude so as not to fly straight into "outer space!" If the Earth were really a sphere 25,000 miles (40,233 km) in a circle with an inclination of 8 inches per mile squared, then a pilot wishing to maintain the same altitude at a typical speed of 500 miles per hour (804 km / h) would have to constantly dive nose down and descend at 2777 feet (846m) every minute! Otherwise, if not corrected, the pilot will be 166,666 feet (51km) higher than expected in an hour! An aircraft flying at a typical altitude of 35,000 feet (10 km), desiring to maintain this altitude at the upper edge of the so-called "troposphere", would be more than 200,000 feet (61 km) 57 in the "mesosphere" in one hour, and the farther it goes fly, the greater the trajectory will be. I have spoken to several pilots and no compensation is being made for the supposed curvature of the earth. When pilots reach the required altitude, their artificial horizon indicator remains level, as does the heading; no required 2777 feet per minute (846 km/min) of tilt is ever taken into account.

ANTARCTIS AND ARTICA DIFFERENT IN CLIMATE

If the Earth were really a ball, then the polar regions of the Arctic and Antarctic at the corresponding latitudes north and south of the equator would have similar conditions and features: similar temperatures, seasonal changes, daylight hours, flora and fauna. In fact, comparable latitudes north and south of the equator in the Arctic and Antarctic regions are very different in many ways. "If the earth is a sphere, according to popular opinion, then the same amount of heat and cold, summer and winter, should be present at the corresponding latitudes north and south of the equator. The number of plants and animals would be the same, and the general conditions would be the same. Everything is as on the contrary, which refutes the assumption of sphericity.The large contrasts between regions in the same latitudes north and south of the equator are a strong argument against the accepted doctrine of the sphericity of the Earth