World Magnetic Model Being Updated a Year Early

The World Magnetic Model—the standard model of the Earth’s magnetic field and a crucial part of modern navigation systems—was last updated in 2015. That update was supposed to last until 2020, but problems with the model started within a year of the last update. As Nature reports, a geomagnetic pulse under South America in 2016 made the magnetic field “lurch”:

By early 2018, the World Magnetic Model was in trouble. Researchers from NOAA and the British Geological Survey in Edinburgh had been doing their annual check of how well the model was capturing all the variations in Earth’s magnetic field. They realized that it was so inaccurate that it was about to exceed the acceptable limit for navigational errors.

As a result, the WMM is being updated a year early—this month, in fact, though the U.S. government shutdown is pushing back the release of the updated model.

Birds Discover Longitude

Eurasian reed warblers don’t need no stinkin’ marine chronometers. A new study suggests that the migratory birds make use of magnetic declination to determine longitude, “at least under some circumstances under clear skies. Experienced migrants tested during autumn migration in Rybachy, Russia, were exposed to an 8.5° change in declination while all other cues remained unchanged. This corresponds to a virtual magnetic displacement to Scotland if and only if magnetic declination is a part of their map. The adult migrants responded by changing their heading by 151° from WSW to ESE, consistent with compensation for the virtual magnetic displacement.”

Not, it would seem, accurate enough for the species to earn a chunk of the Longitude Prize, and it’s not like John Harrison should have been messing about with birds instead of clocks, but interesting all the same. [GeoLounge]