What is the shape of the earth?
1, the shape of the earth: a blue planet similar to a sphere. The shape of the earth has always been one of the important issues discussed and studied by human beings. In ancient times, people generally thought that the earth was flat, but with the development of science and the progress of geography, we gradually realized that the real shape of the earth was similar to a sphere.
2. Sphere theory of the earth: In the 6th century BC, the ancient Greek philosopher Pythagoras put forward the theory that the earth is a sphere, but this view was not widely accepted. Until the 3rd century BC, Eratosthenes, a fisherman from Alexandria, put forward the theory that the earth is a sphere by observing the phenomenon of ships traveling far away, and this theory was gradually accepted at that time.
3. Scientific evidence: Modern science has provided a lot of evidence to support the view that the earth is a sphere: the curvature of the horizon: when an object is farther and farther away from us, its position on the horizon will gradually decline, which is a phenomenon caused by the curvature of the earth's surface. This can be proved by observing the ships at sea gradually disappearing below the horizon.
4. Aerial and space observation: Photographs of the Earth taken from airplanes and spaceships show the spherical shape of the Earth. These photos include photos of famous earth satellites, such as those taken during the Apollo mission to the moon. Earth rotation: the rotation of the earth causes sunrise and sunset. If the earth is flat, then everyone on the earth should see the sunrise or sunset at the same time.
5. Gravitation: Gravitation acts on objects, causing them to fall toward the center of the earth. This phenomenon also supports the view that the earth is a sphere, because only a sphere can attract objects evenly.
6. The earth is slightly flat sphere: Although the earth is described as a sphere, its shape is actually slightly flat, that is, slightly flat between two opposite poles. This shape is called ellipsoid or earth ellipsoid. The rotation of the earth causes this slightly flat shape, which makes the equatorial radius of the earth slightly larger than the polar radius.
7. The view that the shape of the earth is similar to a sphere is supported by a lot of scientific evidence. From ancient philosophers to modern satellites and space probes, the spherical shape of the earth has always been an important topic in scientific research. This discovery not only changed our understanding of the earth, but also had a far-reaching impact on geography, astronomy and navigation technology.