Why is the earth round? Why is the earth round?

It's like a snowball, the dust in the universe is like snow, getting bigger and bigger, and the more round it gets.

According to Newton's law of universal gravitation, there is a force acting between any object. When an object is large enough, it has a large enough gravitational force to overcome its own rigidity to form a round shape. Large objects such as the Earth are round for this reason, and some asteroids are not large enough to become irregular.

However, due to the centrifugal force generated by the rotation of the earth, the earth is elongated, so the earth is elliptical.

By the way, since the Earth is a stony planet, it is not very elliptical, and a gas planet like Jupiter is elliptical.

The Earth is a sphere, but due to gravity, it is not a perfect sphere, and the equator bulges outwards to form a "spare tire" structure. In fact, the polar radius of the Earth is kilometers, while the radius of the equator is kilometers.

Why is the Earth round?

There is a long process of understanding the shape of the earth. Ancient Eastern and Western people were limited by the level of productivity and had a relatively narrow field of vision, so they believed that the sky was round and the earth was square, that is, the so-called"The sky is round"

In ancient Greece BC, people have begun to pay attention to many phenomena, such as: the higher you stand, the farther you can see; Ships approaching from afar always see the mast first, then the hull, and so on, and have an intuitive guess about the shape of the earth.

In the century B.C., the ancient Greek philosopher Pythagoras put forward the idea that the earth is spherical, and Aristotle, another ancient Greek philosopher, based on the fact that the shadow of the moon on the moon is a circle during the lunar eclipse, scientifically demonstrated for the first time that the earth is a sphere.

It was only in 1522 that Magellan and his companions completed a circumference around the earth before they established the idea that the earth was a sphere.

The first to calculate the size of the earth should be said to be the Greek geographer Eratosthenes in the 3rd century BC. He succeeded in triangulating the circumference of the Earth at about 250,000 Greek li (39,600 kilometers), which is only 340 kilometers short of its actual length, which was remarkable 2,000 years ago.

At the end of the seventeenth century, Newton studied the effect of regional rotation on the shape of the Earth, and theorized that the Earth was not a very round sphere, but a slightly uplifted spheroid at the equator and slightly flattened at the poles.

In 1672 the Frenchman J. Richie (J. Francisco)

Richex) placed a pendulum clock in Guyana's Cayenne near the equator, which was accurate in Paris, France, but is now 2 minutes and 28 seconds slower every day. Richet, after studying this phenomenon, believes that this indicates that the Earth is raised near the equator. So I came to the conclusion:

The Earth is not a positive sphere, but an ellipsoid of an oak flatten.

After the 50s of this century, the development of science and technology is very rapid, and a variety of ways have been opened up for geodesy, high-precision microwave ranging, laser ranging, especially artificial satellites in the sky, coupled with the use of electronic computers and cooperation between international reputation, so that people can accurately measure the size and shape of the earth. Through actual measurements, we finally got the exact data. Measurements also found that the Arctic region is about a metre higher and the Antarctic region is 24-30 metres lower.

That's why some people say that the earth is like a big pear lying upside down. In fact, the Earth is a triaxial ellipsoid, to be exact.

The Earth is a sphere and nucleus, but due to gravity, it is not a perfect sphere, and the equator is bulging outwards around it, forming a "spare tire" structure. In fact, the radius of the Earth's poles is kilometers, and the radius of the Absolute Shed is kilometers.

Why is the earth in a circular cavity and trembling? Defeated.

Why is the Earth round?

The Earth is a sphere, but due to gravity, it is not a perfect sphere, and the equator bulges outwards to form a "spare tire" structure. In fact, the polar radius of the Earth is kilometers, while the radius of the equator is kilometers.

Due to the rotation of the Earth, the centrifugal force at the equator is much greater than elsewhere on the Earth. At the poles, the centrifugal force becomes zero. Therefore, the matter must be concentrated towards the equator, so that the equator bulges relative to the poles, that is, the radius of the equator is longer than the radius of the poles, forming a nearly circular oblate sphere.

There is no need to elaborate on this knowledge, and everyone understands it, but why is the earth spherical, not square, not triangular, and not strangely shaped? It starts with the causes of the Earth, gravity and rotation.

Whether it is the theory of catastrophic causes or evolutionary causes, in the process of decay and generation of radioactive materials, sooner or later, the earth is still in a state of high-temperature melting from below the mantle, except for the solidification of a thin crust. The Earth's core may be a hot metal solid due to high pressure. Under the action of gravity, the heavy elements sink and the light elements float.

It then expands from the center of the earth in all directions to the surface, presenting a concentric circle-like structure. In other words, at the same distance from the center of the earth, it is essentially made of the same substance. Therefore, their density is roughly the same, and so is the gravity.

This can be called the gravitational self-balancing mechanism. What kind of shape can ensure the balance of gravity in all directions, of course, only spherical shapes.

At the same time, the high-speed rotation of the earth year after year since its formation is also conducive to the uniform distribution of molten materials in the earth's interior.

However, when a celestial body is too small, the gravity is weak, or the inside of the solid has never been melted, or it was originally a large spherical object, and then it was accidentally smashed into a solidified small object, then the gravitational self-balancing mechanism will lose its effect, and such a celestial body will rarely be round, but oddly shaped. This is the case, for example, with the moons of Mars, as well as with many asteroids. This also proves from the opposite side that only objects with sufficient gravity and an interior that were or are in a molten state can be spherical.

The Earth is one such celestial body.

The movement of objects in the universe is always affected by various gravitational forces, so they both revolve and rotate, and the centrifugal force of rotation shapes them into a spherical shape.

It seems to have something to do with the tension of the object, just like a drop ......of water in a vacuum that takes on a spherical shape

The Earth was created long ago when rocks in the solar system collided with each other to form planets. From the beginning of its formation until the present, the earth has been mainly composed of liquid rocks. In space, where gravity is minimal, liquid matter will automatically form a spherical shape.

This has been demonstrated by experiments conducted by astronauts in the space environment with substances such as water, fruit juice and liquid metal. The Earth is a huge liquid sphere at a considerable distance from the Sun, which gradually forms a circle as it moves through space. Asteroids and small stars such as the moons of Mars are so weak in their gravitational pull that they cannot form a circle once they form a solid star.

Due to the large size of the Earth, its gravitational pull is strong enough to make itself circular. If there is no tectonic plate movement that makes the peaks taller, gravity will make the Earth become more and more round.

When the universe was formed. Many heavy metals are concentrated. And the core of the earth was formed. In turn, it attracts non-heavy metal substances such as dust.

But what is an elliptical shape in the earth is related to the characteristics of the circle and its rotation.

When the core of the earth reaches a certain weight. The gravitational pull will cause the external force to carve. Because of the depression. Approaching the center of a metal with a heavier mass.

And the gravitational pull at the bulge. Because there is the thickness of the earth's crust. Whereas, the gravitational pull is weaker. (Lower depressions under gravity.) Can't attract magma).

And because the metal materials in the center of the earth almost always emit nuclear energy in the early stage. The enormous heat turns the earth into a liquid state. This force is even stronger.

This causes the magma to fill in from the bulge to the recess. It also makes the crust at about the same distance from the center of the earth everywhere. (The distance from any point on the surface of the circle to the center of the circle.)

same) and when the Earth has a centroid. It already rotates. The centrifugal force causes the Earth's equator to be slightly thicker than the meridian circle. That is, to make the earth incomplete and circular. Rather, it is an ellipse.

Who told you that the earth is round?

To be precise, the earth is a polar part.

1. Surface tension.

A drop of liquid suspended in space is spherical! This is due to the action of surface tension.

The Earth is almost liquid except for the solid surface of the Earth, which is a solid surface, and the Sun is even more fluid. Due to the same principle, it is spherical.

Interpretation. 2. Gravitational force. If not affected by external forces, all objects have a tendency to concentrate towards the center under the action of gravitational force. The most concentrated knots.

It's spherical! Although the surface of the earth is solid, it is also deformable because the solid particles are also mobile, which makes it possible to transform it into a spherical shape.

The activity of energy in the Earth's interior makes the Earth irregularly shaped. However, the stones of the mountains are rolled down from a high place by the gravitational pull of the earth (gravitational pull), and the rivers carry the sediment from the high to the low-lying oceans (the rivers also flow by the gravitational pull of the earth)...These are all examples of concentration towards the center, and they all turn the earth from irregular to spherical.

If the Earth's interior ceases to move, it is possible that in many billions of years the Earth will become a very standard spherical shape (with the exception of centrifugal force and the gravitational pull of other celestial bodies).

Many asteroids, due to their own small mass, resulting in their own gravitational force is relatively small, and the star is generally composed of relatively hard solid rock, it is difficult to complete the process of moving to the center under the action of its own gravity, so their shape is strange, oval, rod-shaped.

Not just the Earth, as long as there is enough mass, the planets in the universe are spherical (not round, but spherical).

There are two reasons for this.

One is that all planets are formed by the gravitational condensation of solid particles, dust, and gaseous matter in the universe. During or just after the formation of the planet, the solid matter has not yet become a monolithic stony solid, at least the surface is still free to move, and this free-flowing substance is called a "fluid". All fluid matter (flowable solids and liquids, gases, etc.) have an inherent property of being as close to the center of gravity as possible, and if it can be closer to the center of gravity (i.e., the center of the planet), the matter that is farther away will spontaneously move towards the center of gravity, that is, "downward".

Until all matter is equidistant from the center of gravity (i.e., the center of the sphere). At this time, the object must be spherical. So,The spherical state is also called the "hydrostatic equilibrium state."

The second is that of all geometries, the sphere is the geometry with the smallest surface area under the same volume. Whereas, fluids, when clumped together, have the ability to maintain their minimum surface area. So whenever possible, the planet will remain spherical.

In fact, this is the same principle as the formation of water droplets on lotus leaves. It's just that water droplets rely on the surface tension of water when they are formed, while planets rely on gravity.

The Earth is a sphere, but due to gravity, it is not a perfect sphere, and the equator bulges outwards to form a "spare tire" structure. In fact, the polar radius of the Earth is kilometers, while the radius of the equator is kilometers.

The Earth is not round, but the poles are slightly flattened and the equator is slightly bulging.

The long-term rotation shapes and pushes the circle.

Because all planets don't have squares.