A globe is a sphere or ball that bears a map of the Earth on its surface and is mounted on an axle that permits rotation.
Globes fall into two broad categories: terrestrial and celestial. Terrestrial globes are spherical maps of the world, and celestial globes use the earth as an imaginary center of the universe to map the stars in spherical form.
Globes are made in two standard sizes. The 12 in (30.5 cm) diameter globe (roughly the size of a basketball) is the most popular globe sold to schools and retailers, and the second most popular size is 16 in (40.6 cm) in diameter. Of all the globes sold, 80% of them are 12 in globes.
Globes are made in a variety of color schemes because they are made as ornamental as well as informative objects to decorate homes and offices. Interestingly, children prefer globes with blue oceans, while adults like non-blue globes, of which the antique or off-white color is favored.
Globes are among the most ancient scientific instruments known.
The ancient Greeks, who knew the Earth to be a sphere, were the first to use globes to represent the surface of the Earth. The first known globe, a revolving sphere, was made by Crates of Mallus c. 2nd Century BC.
A highly important contribution to the development of the globe was made in the second century AD by the Alexandrian astronomer and geographer Claudius Ptolemaeus (or Ptolemy). He described a precise scientific method of fixing the position of a place on a globe by using so-called spherical coordinates. Such coordinate systems are the foundation on which all later scientific globes rest. Because of his findings and descriptions, Ptolemy is considered the father of geography.
The knowledge of the round world was taught until the fall of the Greek and Roman Empires c. 4th Century AD and then lost as society slipped into the dark ages.
Early terrestrial globes depicting the entirety of the Old World were constructed in the Islamic world.
During the Middle Ages in Christian Europe, while there are writings alluding to the idea that the earth was spherical, no known attempts at making a globe took place before the fifteenth century.
China made many mapping advancements such as sophisticated land surveys and the invention of the magnetic compass. However, no record of terrestrial globes in China exists until a globe was introduced by the Persian astronomer, Jamal ad-Din, in 1276.
The Erdapfel – German for ‘earth apple’ – is a terrestrial globe produced by Martin Behaim from 1490–1492. The Erdapfel is the oldest surviving terrestrial globe. It is constructed of a laminated linen ball in two halves, reinforced with wood and overlaid with a map painted on gores by Georg Glockendon. The map was drawn on paper, which was pasted on a layer of parchment around the globe.
Another early globe, the Hunt–Lenox Globe, ca. 1510, is thought to be the source of the phrase Hic Sunt Dracones, or “Here be dragons”. A similar grapefruit-sized globe made from two halves of an ostrich egg was found in 2012 and is believed to date from 1504. It may be the oldest globe to show the New World. Stefaan Missine, who analyzed the globe for the Washington Map Society journal Portolan, said it was “part of an important European collection for decades.” After a year of research in which he consulted many experts, Missine concluded the Hunt–Lenox Globe was a copper cast of the egg globe.
The Unisphere in Flushing Meadows, New York, at the Billie Jean King USTA Tennis Center, at 37 m (120 ft) in diameter, is the world’s largest geographical globe. This corresponds to a scale of about 1:350 000. (There are larger spherical structures, such as the Cinesphere in Toronto, Ontario, Canada, but this does not have geographical or astronomical markings.)
The largest revolving globe – a sphere 12.52 m 41 ft 18 in in diameter, weighing 2,540 kg 5600 lb called Eartha was designed and built by Delorme in Yarmouth, Maine, USA in 1998 The globe which took two years to build, rotates and revolves on a specially specially designed cantilever arm and rotates on an axis. It is powered by two electric-powered motors, which are commanded by a computer. It represents the earth as it is seen from space and is housed in a three storey glass atrium.
The Mapparium, three-story, stained glass globe at the Mary Baker Eddy Library in Boston, which visitors walk through its diameter via a 9.1 m (30 ft) glass bridge. This corresponds to a scale of about 1:1.4 million.
The Babson globe in Wellesley, Massachusetts, a 7.9 m (26 ft) diameter globe which originally rotated on its axis and on its base to simulate day and night and the seasons. This corresponds to a scale of about 1:1.6 illion.