The magnetic north pole is currently hovering over the North Sea and moving toward Siberia. This means two Florida airports are renumbering their runways.
Odd as this connection may appear on the surface, the adjustments under way at Tampa International Airport and beginning next week at Peter O'Knight Airport are the result of a natural, ongoing process.
Earth's magnets
The Earth has an iron core, and movement within its outer part is likely responsible for sustaining a magnetic field, which constitutes much of what we measure at the Earth's surface. As a result, the Earth resembles something of a giant magnet with two poles: magnetic north and magnetic south. However, its field is not perfectly symmetrical and has undulations that are always moving around, according to Jeffrey Love, a research scientist with the U.S. Geological Survey's Geomagnetism Program.
The magnetic poles don't line up with the geographic ones, and the difference between them is an angle called declination. As if this wasn't enough of a nuisance for navigators, the Earth's magnetic field drifts, causing the angle of declination to change over time.
In fact, it drifts about one-fifth of a degree a year at lower latitudes, such as Florida. "So that means if you wait five years, the compass will be off by one degree," Love said.
Saturday, January 8, 2011
Earth's Magnetic Field Shifts, Forcing Airport Runway Change
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