Just over 40 years ago, what began as a routine safety test at the Chernobyl nuclear power plant (or Chornobyl in Ukrainian) in Soviet Ukraine spiraled into one of the most recognizable disasters of the 20th century. The reactor exploded and burned, spewing chunks of nuclear debris into the sky. Among that toxic litter were countless tiny “hot particles,” fragments of nuclear fuel smaller than the width of a human hair (somewhere between 8 and 50 micrometers across). Those particles are called hot because they’re highly radioactive, and still are four decades later. Today, scientists entering the areas of the Chernobyl Exclusion Zone where the hot particles are located are required to wear a full protective suit. But after decades of study, scientists still know surprisingly little about what their particles are made of at the molecular level. A team of researchers from Germany recently set out to change that by analyzing six particles collected from two sites in the Exclusion Zone using synchrotron X-ray diffraction. Surprisingly, they discovered the particles remained far more chemically stable …