Physicists find missing link between glass formation and crystallization

Glasses are neither fluids nor crystals. They are amorphous solids and one of the big puzzles in condensed matter physics. For decades, the question of how glass forms has been a matter of controversy. Is it because some regions freeze their thermal motion? Or is it because there are particles or clusters which do not fit to form a crystal? At least for the model system of hard spheres, researchers have now taken a major leap in reconciling these two opposing views. Using a clever combination of