Globe

From Encyclopedia Jr, free information reference for Kids

This article is on a planet-representation device. For others, see globe (disambiguation).

World Globe, centered over Indonesia and the Indian Ocean

A globe with Slovakian place labels. Centred over the Indian Ocean.

Landforms of Southeast Asia, from the relief globe at the Field Museum of Natural History, Chicago

Half of a globe

A globe is a three-dimensional scale model of a spheroid celestial body such as a planet, star or moon, in particular Earth, or, alternatively, a spherical representation of the sky with the stars (but without the Sun, Moon, or planets, because their positions vary relative to those of the stars; however, the ecliptic, along which the Sun moves, is indicated).

[edit] Terrestrial globe

Terrestrial globes are the only geographical representation of Earth that have negligible distortion. Spheres such as the Earth are mapped onto a flat surface using a map projection with an inherent degree of distortion. These projections can either enforce angle preservation or area preservation. A typical scale for a globe is roughly 1:40 million.

The Earth is the most popular planet represented, but globes of the Sun, the Moon and other celestial objects have been made, including fictional ones.

The earliest globe, called the "Nürnberg Terrestrial Globe", was made during the years 1490-1492 by German mapmaker Martin Behaim.

A globe is usually mounted at an angle on bearings. In addition to making it easy to use this mounting also represents the angle of the planet in relation to its sun and the spin of the planet. This makes it easy to visualize how days and seasons change.

Sometimes a globe has relief, showing topography; in the case of a globe of the Earth the elevations are exaggerated, otherwise they would be hardly visible. Most modern globes are also imprinted with parallels and meridians so that one could (if only approximately due to scale) tell where a specific point on the surface of the planet is located.

Mass-produced globes are typically covered by a printed paper map. The most common type has long, thin strips of paper that touch at the equator, and narrow to a point at the north pole and the south pole. [1] Then a small disk is used to paper over the inevitable irregularities at the poles. The more strips there are, the less stretching and crumpling is required to make the paper map fit the sphere. From a geometric point of view, all points on a sphere are equivalent -- one could select any arbitrary point on the Earth, and create a paper map that covers the Earth with strips that come together at that point and the antipodal point. However, as the Earth is an oblate spheroid and not a perfect sphere, bulging slightly at the equator, to correctly represent the true shape of the Earth using such paper strips is more difficult.

[edit] Notable large globes

• Eartha, currently the world's largest rotating globe (41 feet in diameter), at the Delorme headquarters in Yarmouth, Maine
• The Mapparium, 30 foot walk-in globe at the Christian Science complex in Boston, intended to be viewed from within.
• The Babson globe in Wellesley, Massachusetts, a 26-foot diameter globe which originally rotated on its axis and on its base to simulate day and night and the seasons
• The giant globe in the lobby of The News Building in New York City.

[edit] See also

• Dymaxion map
• Celestial globe
• Johannes Schöner globe
• Armillary sphere
• Google Earth
• Virtual globe
• NASA World Wind

[edit] External links

• Replogle Globes -- the world's largest globe maker
• ppmglobe - generate strips to glue onto a sphere
• 3D VRML globe
• 3D Java Globe with coastlines, parallels, meridians, etc.
• Photo of a pocket terrestrial and celestial globe from the Beyer chronometrie clock and watch museum
• World globe facts