October Zoom

Lost? In a situation where natural directional cues are nonexistent? Just whip out your trusty compass and find your way. The function of the compass depends on planet Earth’s magnetic field, which is thought to stem from the convection of liquid iron in the outer core. Despite all the variations across cultures and history, the basic design is the same. Compasses have a magnetic pointer that is attracted to Earth’s north magnetic pole and direction can be extrapolated by how the pointer moves relative to directional markings on the compass itself. Although controversial archaeological evidence points to Mesoamerican Olmecs using compass-like mechanisms around 1400-1000 BC, Chinese inventors are the indisputable fathers of the compass. Literary evidence points to 11th century AD as the time when all the elements came together and the magnetic, direction-finding compass was born. In these early compasses lodestone, a form of the mineral magnetite was used to magnetize the metal pointers. As the compass design spread throughout the world, and into the present day, this magnetizing technique was and is in use. While magnetic compasses are still omnipresent on land and sea, new direction-finding technologies have emerged, such as astrocompasses, which are electronic devices that use the positions of stars to calculate direction. But the big one that has truly been embraced by modern culture is the Global Positioning System or GPS, which utilizes a series of satellites to triangulate one’s position anywhere in the world. But modern directional devices such as GPS has more of what a compass has less of—accuracy. This is because the North Magnetic Pole that compass needles are attracted to is not aligned with the Geographic North Pole. The constantly shifting Magnetic Pole is in the vicinity of Ellesmere Island in the Canadian territory of Nunavut about 500 miles from the Geographic North Pole and is moving northwest at about 26 miles a year. –By Michael Isenbek