I was fascinated by the idea of jet packs when I was a kid. They were sci-fi magic, and the idea that you could strap into an oversized backpack wrapped in tinfoil and fly around was very enticing.

An illustration of a person in a lab coat looking at a picket fence. The field is various elements, metals specifically. Credit: Chris Gash On a summer day about 20 years ago, Paul Chirik returned to ...