Millions of cosmic particles called muons bombard Earth every day. Heavier atoms in dense elements like plutonium and uranium deflect these particles more than lighter atoms. For researchers at Decision Sciences, this inviolable fact of physics makes finding hidden nuclear material at ports and borders simple: A packing crate with a nuke inside is going to deflect particles. This year, the company rolled out the first commercial nuclear detector that analyzes these deflection patterns. The system can scan a truck in less than a minute, mapping the source of deflected muons as they glance off the cargo. It’s faster and more reliable than x-ray scanners, which often can’t see through steel or lead.