In August of1905, a strange ship set sail from San Francisco Bay. The wooden brig, called Galilee— also the name of the sea where Jesus, riding in a boat himself, as soon as apparently relieved a storm– had been retrofitted for a brand-new task: The Carnegie Organization‘s Department of Terrestrial Magnetism wanted to cruise it around the Pacific Ocean, to determine and map the planet’s electromagnetic field. That field matters, in part, for navigation. To navigate utilizing a compass, you need to understand how away magnetic north is from the fixed north on your map. And for that, you need a quite precise idea of how this field drapes throughout the planet.
To that end, workers eliminated all the magnetic parts they might from Galilee, swapping, for instance, the steel rigging out for hemp rope, and building a brand-new spot high above the ship’s iron bolts, where the scientific devices would feel their results less acutely. Galilee swashbuckled through the seawater up until 1908, but its science was constantly stormy: The material changes were never ever quite good enough.
” There was excessive metal in the boat,” says Mike Paniccia of the National Geospatial-Intelligence Agency. That agency, the NGA, is today in charge of distributing exactly the sort of magnetic-field information the Galilee sought. And it’s presently running a contest called MagQuest, whose last phase started on March 18, to find cool, unique methods to collect that information. The competitors reaches out to universities, laboratories, and personal companies, asking for their most innovative brand-new ways to map magnetism.
Back in the early 20 th century, the “innovative brand-new way” was just to construct a better mousetrap ship. Soon, the Carnegie Organization constructed its own vessel from the waterline up– appropriately named the Carnegie It had nearly no magnetic meddling. Its metal was limited mostly to copper and bronze, which do not react to the twists and turns of magnetism. The Carnegie cruised, sucking up data all the while, for 20 years. (Then it exploded during a refueling session– RIP).
You may wonder why, after making 20 years’ worth of magnet maps, people need more of them. It turns out that you can’t just one-and-done map Earth’s magnetic field, since it’s moving all the time. One must redraw and redraw and redraw.
That continuous upgrading was smoother cruising when airplanes might catch magnetic-field information. Today, the job mostly falls (up) to satellites, whose readings feed into the World Magnetic Model, which the NGA releases every 5 years or so (often sooner if the field is changing a lot). It becomes part of a bigger program called the World Geodetic System 1984, which also has designs for gravity and geographical coordinates. Its objective, as Paniccia puts it, is “defining th
