These are tiny solidified hydrogen particles used to make the flow of superfluid helium visible. When liquid helium is cooled below a critical temperature of around -450.20° Fahrenheit (2.17 Kelvin), it becomes a superfluid with zero viscosity. In regular fluids, tracer particles are carried along by viscous forces to visualize flows, but this method does not work in superfluid helium due to zero viscosity. Instead, the particles become trapped by vortices (i.e., tiny whirlpools), allowing researchers to observe the "invisible" flow. The original video was created September 2022. This picture was clipped March 2023.