Magnetic Variation (MagVar), also known as magnetic declination, is the angle on the horizontal plane between True North (the geographic North Pole) and Magnetic North (the direction a compass needle points).
Because the Earth’s magnetic field is fluid, constantly shifting, and misaligned with the planet’s rotational axis, this angle changes depending on both a traveler’s specific geographic location and the current year. Tracking this dynamic shift is a fundamental science that directly impacts global navigation, military operations, aviation, and consumer technology. The Core Science Behind MagVar
The earth’s magnetic field acts like a chaotic, living shield. It is driven by massive subterranean forces that prevent MagVar from ever staying static.
The Geodynamo: Earth’s magnetic field is generated deep within the planet by the outer core, a 2,200-kilometer-thick layer of liquid iron and nickel. As the Earth rotates, convection currents driven by heat escaping the inner core move this molten metal, generating massive electrical currents that produce the global magnetic field.
Secular Variation: Because the liquid metal in the core sloshes, churns, and changes speed, the magnetic field it creates is highly unstable. This slow, continuous change in the field’s strength and direction over time is known as secular variation, which causes MagVar lines to warp and move continuously across the globe.
The Shifting Pole: Magnetic North is not a fixed spot. It has a long history of drifting away from northern Canada toward Siberia. In the 1990s, it accelerated to an unprecedented speed of 55 kilometers per year before slowing down to roughly 35 kilometers per year, completely shifting MagVar baselines worldwide. Tracking and Modeling MagVar
Because you cannot visually look at the sky to find Magnetic North, scientists must map it using a dense network of high-tech instruments. World Magnetic Model 2025 Released | News
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