Globe, a model of the earth or of the heavens. Globes are a kind of map. Most globes are formed from a series of roughly triangular maps called gores, which are glued on the outside of a sphere.
Globes that represent the earth’s surface are called terrestrial globes. Most of these globes represent the political features or relief (physical) features of the earth by colors printed on a smooth surface. A molded three-dimensional surface is used on some relief globes to represent the surface of the earth with miniature mountains, valleys, and other physical features.
Globes are often made to rotate around a rod that pierces them at the poles. The rod, which serves as the axis of the globe, is attached to a stand. The axis is usually inclined at an angle of about 23.5°, the amount by which the axis of the earth is tilted off the axis of the sun. Some globes are placed in a mounting, or stand, that cradles the globe and allows it to be turned in any direction so that any part of the world can be easily examined.
A celestial globe is one on which the relative positions of the stars are mapped without distortion. It is a model of the heavens as seen from the earth. Each star is plotted on the globe at the point corresponding to the spot on the earth where it appears to be directly overhead. Some celestial globes are large enough for observers to enter, stand in the center, and look out at the heavens as if they were standing at the center of the earth. Some such globes are transparent, and others have the stars displayed on their inner surface. Small celestial globes are viewed from outside, like a terrestrial globe, and display the star map turned inside out.
Unlike flat maps, globes can represent the earth’s curved surface without distortion. Globes are often used to plan long sea and air routes, called great-circle routes, and to determine the routes of satellites. They are also used to trace earthquake shocks and tsunamis (tidal waves). All of these routes are measured better on a globe than on a flat map because they are not straight lines: they follow the earth’s curvature.
Globes have some disadvantages. They are somewhat bulky and cannot be stored easily. In addition, globes would have to be gigantic to show small areas, such as those of a state in the United States, in great detail.
The first globes were built by the ancient Greeks. The earliest known globe was one said to have been constructed by the scholar Crates about 150 bc. An ancient celestial globe that still exists was made about 150 ad as part of a sculpture, called the Farnese Atlas, in the Naples Museum, Naples, Italy. The oldest existing terrestrial globe was made by Martin Behaim in Nürnberg, Germany, in 1492. This globe does not show the Americas. As new lands were discovered in the 16th and 17th centuries, globes became more accurate.
The world’s largest globe is the Unisphere, which was built for the 1964 New York World’s Fair. This stainless steel globe is 37 m (120 ft) across and weighs 408,000 kg (900,000 lb), including its base. The world’s largest revolving globe is the Globe of Peace, in Pesaro, Italy, measuring 10 m (33 ft) across and weighing 33,500 kg (73,900 lb).