World Globes
World globes are near-universal teaching aids that you can find on any student's table or in any geography class. A sphere that represents our world seems to be a very normal and commonplace idea in the present day. Strange as it may seem, this wasn't always so. Mankind's idea about the shape of the world they live in had to undergo a certain radical change before it was possible to construct the first world globe.
Civilized human beings have lived on earth for many thousands of years. Yet the first world globe wasn't ready until the year 1492, a mere five hundred years ago. What was behind this extraordinary delay? What held back the inception of this intuitive model of the world which seems so natural to us today?
The problem was that we didn't know for sure that the earth was round. Yes, astounding as that may seem today, this is absolutely true. Since ancient times, astronomical observations and indirect indications have prompted many philosophers to speculate that we live on a spherical surface. Among them were such illustrious names as Ptolemy and Aristotle. But there was no conclusive evidence to establish this model, and neither was the true size of the planet known. In fact, many people believed that the earth was flat, and you might fall off one of its edges if you traveled too far in any one direction! Some continue to believe this even today; for example, there is this community called the Flat Earth Society, based in England and with over three thousand members! Here's a link to their website, if you're interested.
It took the gradual improvement in navigational technology to reach a certain level before it was possible for people to undertake he task of sailing around the world, with a realistic hope of success. However, even in the time of Christopher Columbus, the exact size of the earth's sphere was not known. He was actually looking for a sea route to India, and upon reaching the shores of a new continent, thought that he had achieved his target. Which is why native Americans were called 'Indians' in the first place, but that's another story.
Since Martin Berhaim's initial effort of 1492, world globes have evolved greatly. Modern world globes are made using specially printed high-definition computerized maps which take into account the distortion that must occur when converting a flat surface into a bent one. Then this is superimposed on the sphere of the globe.
Modern globe printing technology tries to preserve accuracy based on two mutually exclusive principles. First, there is the doctrine of angle preservation, in which the calculations are made so that the angle of each curve is preserved, and the direction and shape of each land mass or water body is exactly reproduced. However, under this doctrine the size of each geographically significant entity on the globe may not be accurate.
And then again there is the doctrine of area preservation, which endeavors to exactly replicate the area of each geographical entity, but in the process must give up some accuracy regarding angle, position and shape.
Since globes are not used as principal resources in mission-critical situations, these slight degrees of deviation are not significant. However, reputable manufacturers often provide information regarding which principle was used in the construction of a particular globe, and the customer may choose the one that suits him best.
The world's largest globe can be found in the town of Yarmouth, Maine, and it is 41 feet in diameter. Another large world globes can be seen in the Christian Science Complex in Boston. This one is 30 feet in diameter and you can walk right into it and view it from within. They have named it Mapparium.
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