Welcome to You Ask Andy

Brian Hallman, age 11, of Lowell, Mass., for his question:

WHO MADE THE FIRST GLOBE OF THE EARTH?

A globe is a map that has been pasted or printed on a hollow sphere. A globe of the earth is called a terrestrial globe and the first one was made in 1492 in Nuremberg, Germany, by a map maker named Martin Behaim.

Most terrestrial globes consist of a series of triangular or tapering strips of paper called gores, which have been pasted onto a sphere. A world map is printed on the gores.

Globes have many uses. They are used widely in the study of geography and can be found in many classrooms and libraries. They are also useful in planning sea and air routes and in establishing radio communications.

Only a globe can give a correct picture of the earth as a whole. Because the surface of a globe is rounded like the earth's surface, a globe represents all parts of the earth's surface true to scale. Distances, areas and directions can be observed without the distortion caused by projections used for flat maps.

The proportions and positions of land features and oceans in relation to each other are seen on a globe exactly as they are on earth. The shortest distance between two points on the earth or a globe is called a great circle. Navigators make use of the great circle route in planning ship and air lanes. A great circle can be measured directly on a globe.

Globes may be mounted on a center axis to show how the earth rotates, or they may be placed in a cradle without attachment.

With special accessories, many different relationships between the earth and the sun can be demonstrated on a globe. Such relationships include the length of daylight, time differences and satellite paths.

Few globes are more than 18 inches in diameter. However, the Langlois Globe, produced in France in 1824, measures 128 feet in diameter and is probably the largest globe in the world.

A globe which is a map of the heavens is called a celestial globe.

The earth itself is a great sphere and is often referred to as "the globe."

Great circle routes are the shortest, most direct routes between any two points on the earth's surface. Airplane navigators have special maps for great circle routes that show distances the same way as a¬globe would show them. Great circle maps give a truer picture of the earth's surface than most flat maps.

Great circle routes can be drawn on aviation maps with straight lines. any of these lines is the edge of a great circle as seen from above a sphere.

Ship navigators can also use these maps to plot their rhumb lines. Rhumb lines are a series of connected straight lines that closely follow a great circle route.

Airplanes use radio instruments for navigating. Radio beacons follow great circle paths. So an airplane homing on a radio signal will follow a great circle route.

 

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