Have you ever wondered how naval crews determine their location while out at sea? These days, most sailors use a Global Positioning System—commonly known as “GPS”—to navigate ships. GPS uses a series of satellites orbiting the earth to send a unique signal to a GPS device sitting on or near the earth’s surface. To calculate the location, a GPS device must be able to read the signal from at least four satellites. However, a variety of sources, including other radio emissions or changes in weather up in space, can interfere with a GPS signal. So what happens if the GPS device aboard a ship cannot detect a signal? All is not lost. Long before the invention of GPS, naval crews utilized angular measurements between celestial bodies (such as the sun, moon, a star, or a planet) and the visible horizon in order to the find their way. This process, known as celestial navigation or astronavigation, provides a reliable way to know a boat’s location. Celestial navigation is an intuitive form of navigation that comes naturally to all living things. If you can locate a fixed, known reference point, you are on your way to finding your location. Fortunately, the captain and crew of their Disney Wonder cruise knew exactly where they were at all times, so the STEAM Team was able to experience whales, ride in a sea plane over endangered glaciers, pan for gold, and fish for a salmon dinner. Keep an eye out for Cassie and Jesse as they learn more about Science, Technology, Engineering, Art and Math in the next episode of the STEAM Team. For more information on celestial navigation, check out these articles on PopSci.com:
Dung Beetles Navigate By The StarsA Mariner’s Tool Could Help Astronauts Navigate Alien Worlds
