"Pick up your cell phone and look at it.
That rectangular marvel of modern technology contains thousands of lines of code. Among them is the World Magnetic Model (WMM) - a program that helps your phone navigate. And it's in a bit of trouble.
Researchers have announced that the WMM needs an emergency update because Earth's magnetic field is changing."
Savvy backcountry hikers have long known that compass needles don't really point north.
The magnetic north pole is displaced hundreds of miles from the true north pole and, to make matters worse, it wanders unpredictably from year to year.
To find true north in the continental USA, you have to correct compass directions by as much as 20 degrees using a special 'declination table.' The World Magnetic Model is a computer program that makes this correction for you.
It improves the navigation of devices ranging from nuclear submarines to common smartphones.