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Desert Diary
Physics/Going North

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We're all taught that a compass points north. There's only one difficulty with this—it isn't true. At least, not for most places on earth. The difficulty is that the magnetic north pole, the direction in which a compass points, isn't at the geographic north pole. Instead, it's in the Arctic Ocean north of Canada. To be specific, when last checked, in 2001, it was at 81.3° north latitude and 110.8° west longitude and moving approximately northwest at around 25 miles per year.

In El Paso, in 1900, a compass pointed 11.6° east of true north. In 2005, it points 9.48° east of true north, and as the magnetic north pole moves westward, the compass points farther west at a rate of about 0.1° per year. On the other hand, if you are in Boston, Massachusetts, the compass points 15.43° west of true north. No wonder travelers in the past relied mostly on the sun and stars. Otherwise, where you were and where you were going would be a complete mystery!
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Contributor: Arthur H. Harris, Laboratory for Environmental Biology, Centennial Museum, University of Texas at El Paso.

Desert Diary is a joint production of the Centennial Museum and KTEP National Public Radio at the University of Texas at El Paso.

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