Earth's Shape: Spherical Proof

Evidence of Earth's Spherical Shape

• The sighting of a ship approaching the shore, where the mast is visible first, then the deck, and finally the entire ship, proves the Earth's surface is curved.
• The Earth's appearance from space, with its blue color and 70% water coverage, also supports its spherical shape.
• The Bedford Level Experiment demonstrates the Earth's curvature, where poles of the same height were found to be 5m higher at one end of the canal compared to the other.

The Shape of the Earth

• The Earth is not a perfect sphere, but rather an oblate spheroid, bulging at the equator and flattened at the poles.
• Ancient astronomers, such as Anubharta and Pythagoras, believed in the Earth's round shape.
• The Earth's shape is described as a geoid.

The Earth's Structure

• The Earth is composed of three main layers: the crust, mantle, and core.
• The crust is the thin, rocky outer layer, with varying thickness under the oceans and continents.
• The mantle is the thickest layer, made up of hot, dense, and mostly solid rock.
• The core is the innermost layer, consisting of a very hot, dense, and mostly liquid iron and nickel.

Plate Tectonics

• The Earth's crust is divided into large plates that move and interact with each other.
• The process of plate tectonics causes mountains, volcanoes, and earthquakes.
• The Earth's surface is constantly changing due to plate tectonics.

The Earth as a Planet

• The Earth is part of the solar system, and all planets are spherical in shape.
• The Earth's rotation causes it to bulge at the equator, making it an oblate spheroid.
• The Earth's shape and rotation are supported by evidence from circumnavigation, sunrise and sunset, and the effects of sunlight on its surface.