earth’s magnetic field

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MagQuest: Measuring Earth’s Magnetic Field With Space-Based Quantum Sensors

December 9, 2025 by 8 Comments

Recently the MagQuest competition on improving the measuring of the Earth’s magnetic field announced that the contestants in the final phase have now moved on to launching their satellites within the near future. The goal here is to create a much improved World Magnetic Model (WMM), which is used by the World Geodetic System (WGS). The WGS is an integral part of cartography, geodesy and satellite-based navigation, which includes every sat nav, smartphone and similar with built-in GNSS capabilities.

Although in this age of sat navs and similar it can seem quaint to see anyone bother with using the Earth’s magnetic field with a compass, there is a very good reason why e.g. your Android smartphone has an API for estimating the Earth’s magnetic field at the current location. After your sat nav or smartphone uses its magnetometer, the measurements are then corrected so that ‘north’ really is ‘north’. Since this uses the WMM, it’s pertinent that this model is kept as up to date as possible, with serious shifts in 2019 necessitating an early update outside of the usual five-year cycle.

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Ask Hackaday: Earth’s Magnetic Field Shifting Rapidly, But Who Will Notice?

March 6, 2019 by 92 Comments

Just when you though it was safe to venture out, the National Oceanic and Atmospheric Administration released an unexpected update. Magnetic North is on the move — faster than expected. That’s right, we know magnetic north moves around, but now it’s happened at a surprising rate. Instead of waiting for the normal five year interval before an update on its position, NOAA have given us a fresh one a bit earlier.

There are some things that we can safely consider immutable, reliable, they’ll always be the same. You might think that direction would be one of them. North, south, east, and west, the points of the compass. But while the True North of the Earth’s rotation has remained unchanged, the same can not be said of our customary method of measuring direction.

Earth’s magnetic field is generated by a 2,000 km thick outer core of liquid iron and nickel that surrounds the planet’s solid inner core. The axis of the earth’s internal magnet shifts around the rotational axis at the whim of the currents within that liquid interior, and with it changes the readings returned by magnetic compasses worldwide.

The question that emerged at Hackaday as we digested news of the early update was this: as navigation moves inexorably towards the use of GPS and other systems that do not depend upon the Earth’s magnetic field, where is this still relevant beyond the realm of science?

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