What is the earth, what is the earth?

Earth is one of the eight planets in the solar system, and is the third planet in descending order from closest to farthest from the sun. It has a natural satellite --- the Moon, which form a celestial system --- the Earth-Moon system.

The Earth rotates from west to east while revolving around the Sun. The combination of the Earth's rotation and its orbital motion produces the alternation of day and night and the changing seasons on Earth. The speed at which the Earth rotates is uneven.

The inertial centrifugal force generated by the rotation of the earth causes the spherical earth to gradually expand from the poles to the equator, becoming the current slightly flattened spheroid, with a polar radius about 21 kilometers shorter than the equatorial radius.

Rotation and revolution.

In 1543, Copernicus first put forward the concept of the earth's rotation and revolution in its book "On the Motion of the Heavenly Bodies". Since then, numerous observations and experiments have proved that the Earth rotates from west to east while revolving around the Sun. In 1851, the French physicist Foucault successfully conducted a famous experiment (Foucault's pendulum test) in Paris to prove the rotation of the Earth.

The Earth's rotation period is about 23:56:4 seconds mean solar time, and the Earth's orbit is elliptical. The semi-major diameter of the orbit is 149597870 km, the eccentricity of the orbit is one sidereal year, the average speed of the orbit is kilometers per second, and the angle between the ecliptic and the equator (yellow-econus angle) is 23°27. The combination of the Earth's rotation and its orbital motion gives rise to the Earth's day-night cycle, the change of seasons, and the distinction of the five zones (tropical, north-south temperate, and north-south cold zones).

The speed of the Earth's rotation is uneven, with long-term, seasonal, and irregular variations. At the same time, due to the gravitational effects of the sun, moon and planets, as well as the various effects of the atmosphere, oceans and internal materials of the earth, the direction of the earth's axis of rotation in space and the earth's body will change, that is, precession and nutation, pole shift and yellow-red angle changes.

Earth is the third planet in the solar system from the inside to the outside, and it is also the terrestrial planet with the highest diameter, mass, and density in the solar system. It is also often referred to as the world. The English word earth comes from Old English and Germanic languages.

The Earth is 4,446 billion years old, and a natural satellite, the Moon, orbits the Earth in a 30-day cycle, while the Earth rotates in a cycle of nearly 24 hours and orbits the Sun in a one-year cycle. Disney has a documentary of the same name.

The name "earth" comes from the Old English word "eorthe". When people don't know that the earth is a planet, the word "earth" simply denotes the earth on which people walk. Later the word denoted not only the earth under our feet, but gradually the whole world itself.

As for when the word appeared, there is no way to verify. Earth is one of the eight planets in the solar system, the international name is "Gaia", and it is the third planet in order of being from the sun. It has a natural moon--- the Moon, which form a celestial system --- the Earth-Moon system.

Map of the Earth's location.

1. The planet inhabited by human beings, one of the eight planets in the solar system, has an average distance of 149.6 million kilometers from the sun, ranking third among the planets, and its equatorial radius is kilometers, ranking fifth among the planets in terms of size.

2. Refers to the whole world: if the youth is strong on the earth, the country is strong on the earth.

Qing Liang Qichao's "Ice Room Collection: Anthology".

3. The earth is an irregular spheroid with slightly flattened poles.

The Earth rotates from west to east while revolving around the Sun. The combination of the Earth's rotation and its orbital motion gives it the day-night alternation and the seasons on Earth (the speed of the Earth's rotation and revolution is uneven). At the same time, due to the gravitational influence of the sun, the moon, and nearby planets, as well as the earth's atmosphere, oceans, and internal materials, the direction of the earth's axis of rotation in space and the earth's body changes.

The inertial centrifugal force generated by the rotation of the Earth causes the spherical Earth to gradually expand from the poles to the equator, becoming the current slightly flattened spheroid, with a polar radius about 21 kilometers shorter than the equatorial radius.

The time when the Earth accumulated from the primordial solar nebula to form a planet to the present. The current best estimate of the Earth's age is 100 million years, and what is commonly referred to as the Earth's age is its astronomical age. The astronomical age of the Earth refers to the time when the Earth began to form to the present, which is closely related to the hypothesis of the origin of the Earth.

The meaning of the word is also "earth". The third planet in the solar system close to the sun, with slightly flattened poles and a slightly bulging equator, is surrounded by an atmosphere, and its surface is land and sea, where humans, animals and plants live.

That's a really advanced question

The earth is round, and there is life in it

Including you, are you also a life on earth?

If the earth is **, then we are all finished

Earth is one of the eight planets in the solar system, the third planet in order from near to far, and it is also the terrestrial planet with the largest diameter, mass and density in the solar system, 100 million kilometers away from the sun. The Earth rotates from west to east while revolving around the Sun. It is 4,04.6 billion years old, and it has a natural satellite, the Moon, which forms a celestial system, the Earth-Moon System.

It originated from the primordial solar nebula 4.6 billion years ago.

The radius of the Earth's equator is kilometers, the polar radius is kilometers, the average radius is about 6,371 kilometers, and the circumference of the equator is about 40,076 kilometers. The surface area of the earth is 100 million square kilometers, of which 71% is oceans and 29% is land.

The interior of the earth has a core, mantle, and crust structure, and the outside of the earth has a hydrosphere, atmosphere, and magnetic field. The Earth is the only celestial body in the universe where life is known to exist, and it is home to millions of living beings, including humans.

The English earth has several meanings such as "earth, earth, land, beast's den" and so on.