Why does the planet act like a giant magnet?
One scientist is building his own Earth to find out
Dan Lathrop needs a bigger Earth. His old one is two feet across and 500 pounds, about 20 millionths the size of the real thing. And after four years of tests, it failed to generate a magnetic field similar to the real Earth’s, which shields us from the sun’s radiation and guides some navigation systems by pointing compasses north.