A globe is a spherical model of Earth, of some other celestial body, or of the celestial sphere. Globes serve similar purposes to maps, but unlike maps, do not distort the surface that they portray except to scale it down. A globe of Earth is called a terrestrial globe. A globe of the celestial sphere is called a celestial globe.

A globe shows details of its subject. A terrestrial globe shows land masses and water bodies. It might show nations and prominent cities and the network of latitude and longitude lines. Some have raised relief to show mountains. A celestial globe shows stars, and may also show positions of other prominent astronomical objects. Typically it will also divide the celestial sphere up into constellations.

The word "globe" comes from the Latin word globus, meaning "sphere". Globes have a long history. The first known mention of a globe is from Strabo, describing the Globe of Crates from about 150 BC. The oldest surviving terrestrial globe is the Erdapfel, wrought by Martin Behaim in 1492. The oldest surviving celestial globe sits atop the Farnese Atlas, carved in the 2nd century Roman Empire.

Flat maps are created using a map projection that inevitably introduces an increasing amount of distortion the larger the area that the map shows. A globe is the only representation of the Earth that does not distort either the shape or the size of large features – land masses, bodies of water, etc.

The circumference of the Earth is quite close to 40 million metres.[1][2] Many globes are made with a circumference of one metre, so they are models of the Earth at a scale of 1:40 million. In imperial units, many globes are made with a diameter of one foot, yielding a circumference of 3.14 feet and a scale of 1:41,777,000. Globes are also made in many other sizes.

Sometimes a globe has surface texture showing topography; in these, elevations are exaggerated, otherwise they would be hardly visible. Most modern globes are also imprinted with parallels and meridians, so that one can tell the approximate coordinates of a specific place. Globes may also show the boundaries of countries and their names, a feature that can quickly become out of date, as countries change their names or borders.

Many terrestrial globes have one celestial feature marked on them: a diagram called the analemma, which shows the apparent motion of the Sun in the sky during a year.

Globes generally show north at the top, but many globes allow the axis to be swiveled so that southern portions can be viewed conveniently. This capability also permits exploring the earth from different orientations to help counter the north-up bias caused by conventional map presentation.

This page was last edited on 1 July 2018, at 17:07 (UTC).
Reference: under CC BY-SA license.

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