What exactly is the shape of the earth and what is the shape of the earth

The Earth is an elliptical sphere with slightly bulging equators and slightly flattened poles

Earth is one of the nine 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.

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 itself must change. 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.

An ellipsoid close to a sphere. Therefore, we often say that gravitation is not equal to gravity, on the one hand, because the earth is not a sphere, and on the other hand, the gravity we are subjected to is the net force of gravity and friction.

An ellipsoid close to a sphere. It's not round.

A pear-shaped shape that resembles a sphere. The North Pole part is a little narrower, and the South Pole part is a little wider.

It is a slightly flattened sphere at the north and south poles.

It is a sphere that is wide in the east-west direction.

The shape of the Earth: an irregular sphere with slightly flattened poles and slightly bulging at the equator.

The shape of the Earth is roughly ellipsoidal. The effect of the Earth's rotation causes a slight flattening along the Earth's axis running through the poles and a slight uplift near the equator. From the Earth's core, the Earth's equatorial radius is 43 kilometers (27 miles) higher than its polar radius.

Thus, the farthest point on the Earth's surface from the Earth's center of mass is not Mount Everest, the highest elevation, but the summit of Mount Chimborazo in Ecuador, located on the equator.

The Earth's reference spheroid has an average diameter of about 12,742 kilometers (7,918 miles), which is about equal to (40,000 kilometers) This integer is not a coincidence, but because the unit of length in the meter was originally defined as one-ten-millionth of the distance between the equator and the North Pole on the meridian passing through Paris, France.

The value of gravitational acceleration ga at a certain sea level at the equator, the value of gravitational acceleration at a certain sea level at the North Pole g, the universal standard value of gravitational acceleration g, and the Earth's rotation period is 23 hours, 56 minutes and 4 seconds (sidereal days), that is, t.

Description of the shape of the earth:

The Earth deviates slightly from the ideal spheroid due to local terrain fluctuations, but on a planetary scale, these fluctuations are small compared to the Earth's radius, and the maximum deviation is only due to the Mariana Trench, which is located at 10,911 meters (35,797 feet) below sea level, and Mount Everest, which is 8,844 meters (29,016 feet) above sea level.

If you shrink the globe to the size of a billiard ball, places like large mountains and trenches on Earth will feel like tiny imperfections, while most of the rest of the planet, including the Great Plains and Abyssal Plains of North America, will feel smoother. The total area of the earth is about 100 million square kilometers, of which about 100 million square kilometers) is land, and the rest of the 100 million square kilometers) is water.

The land mass is mainly in the northern hemisphere, with five continents: Eurasia, Africa, the Americas, Australia and Antarctica, as well as many islands. Oak Wheel Hunger.

The ocean includes the Pacific, Atlantic, Indian, Arctic and Southern oceans and their affiliated seas. The coastline is 10,000 kilometers long. The lowest point on land:

Dead Sea (-418 m), lowest point in the world: Mariana Trench (-11,034 m), highest point in the world: Mount Everest (m).

The Earth is an irregular elliptical sphere with slightly flattened poles and a slightly bulging equator. The inertial centrifugal force generated by the rotation of the earth causes the earth to gradually expand from the equator to the poles, becoming the shape of the current slightly flattened spheroid.

The semi-major axis of this spheroid, i.e., the radius of the Earth's equator, is kilometers, and the semi-minor axis, i.e., the radius of the poles of the Earth, is kilometers, and the flattening rate is about 1 298.

Related information: Mankind has been exploring for a long time, and Magellan was the first to achieve a circumnavigation around the world, confirming that the earth is a sphere. With the development of human science and technology and the application of modern detection technology, people finally discovered that the earth is an irregular sphere with slightly flattened poles and slightly bulging equators.

Well-developed scientific means have opened up a variety of avenues for earth surveying. Through measurements and analysis, people finally got the exact data: the average equatorial radius of the earth is kilometers, and the polar radius is kilometers.

The measurements also found that the Arctic region was about a metre higher and the Antarctic region was 24.30 metres lower. The shape of the earth, it seems, is like a pear: its equatorial part bulges, which is its "pear body"; The North Pole is a bit pointed, like a "pear"; The South Pole is a bit concave and resembles a "pear navel", which is why the Earth is called the "Pear-shaped Earth".

To be precise, the Earth is a triaxial ellipsoid.