If the Earth were flat, ships would simply sail away until they disappeared from view, without any part of them sinking below the horizon. The fact that ships disappear over the horizon is therefore strong evidence that the Earth is round.
Here is a more detailed explanation of the phenomenon:
* The Earth's radius is approximately 6,378 kilometers (3,963 miles). This means that the Earth's surface curves away from the center of the planet by about 8 meters (26 feet) per kilometer (0.6 miles).
* As a ship sails away from the shore, its hull gradually sinks below the horizon because the Earth's curvature causes the water to curve away from the ship. The sails remain visible for a longer period because they are higher up and therefore less affected by the curvature of the Earth.
* The distance at which a ship disappears over the horizon depends on the height of the ship's sails. The higher the sails, the further the ship will be visible before it disappears over the horizon.
* The phenomenon of ships disappearing over the horizon is not unique to Earth. It occurs on any spherical object, such as a planet or a moon.
The appearance of ships disappearing over the horizon is just one of many proofs that the Earth is round. Other proofs include:
* The Earth's shadow on the Moon during a lunar eclipse is always round.
* The stars that are visible from the Northern Hemisphere are different from the stars that are visible from the Southern Hemisphere.
* The Earth's gravity pulls objects towards its center, which is why objects fall down.
Taken together, these proofs provide overwhelming evidence that the Earth is round.
