by Joan Marie Galat
The oldest known map was written on a Babylonian clay tablet in about 2300 BC. People have appreciated how knowledge can be conveyed through maps for a very long time! Early diagrams on paper were drawn by hand but before mass production was possible, most people needed other methods to find their way around. Verbal directions, landmarks, and an understanding of landscape were vital. Knowledgeable desert travellers used, and still use, the shape of sand dunes to determine direction based on predominant wind patterns.
For centuries, explorers and other travellers have depended on the Sun, Moon, and stars to gather navigation information. While it has become the norm in North America and many other parts of the world to use global positioning system (GPS) technology, satellite images, and other technologies to find directions, it’s still useful to know one of the basics—how to find the North Star.
Named Polaris, the North Star is part of the Little Dipper, also called Ursa Minor. Although it’s an important star, it’s not the biggest or brightest star in our night sky. If you could visit the North Pole, lay on your back, and look straight up, Polaris would be the star you see nearly directly overhead.
Try to find Polaris on a dark, clear night. Begin by giving your eyes 30—45 minutes to adjust to the dark. Face north and make two fists, tucking your thumbs to one side instead of overtop your index fingers. To find the North Star, stretch your arm straight out in front of you and place one fist atop the other. Now repeat this maneuver, going hand-over-hand the same number of degrees as your latitude. You can find your latitude, on a globe or map of Earth.
Suppose you live 60 degrees North of the equator. You would go fist-over-fist six times, then follow the path your arm makes into the sky and search that area for the North Star—on the tip of the Little Dipper’s handle. Once you learn the Little Dipper’s location in the night sky, it’s easy to spot and simple to use to determine each of the compass points.Orion is also an easy constellation to use find direction. The three bright stars that form Orion’s belt rise near due east and set near due west.
In the 1700s, people often became lost at sea because they did not know how to determine their longitude, which cannot be determined using the stars. The Discovery of Longitude, 2013 winner of the R. Ross Annett Award for Children’s Literature, is a historical picture book which explains how a carpenter, John Harrison, devoted his life to solving the problem of finding directions east and west at sea.
Despite his dedication and hard work, it took the King of England to make sure he got the recognition he deserved. Thanks to Harrison’s work, everyone on Earth recognizes the same time zones and navigation is much easier than it was when maps were made on clay tablets!
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