Fluctiation experiment in microgravity informing diagnostic methods for industrial and biomedical research

When two miscible liquids are in contact, their molecules move randomly and give rise to a fine mixing that fluctuate constantly. Taken to space, research into equilibrium fluctuations has helped develop diagnostic methods for industrial and biomedical research. In 2007, an unmanned Foton-M3 spacecraft flew around Earth for 12 days with the suitcase-sized Gradflex experiment on board. Gradflex provided the first experimental evidence that diffusion processes are accompanied by giant fluctuations in microgravity. The experiment is a textbook example of fundamental research. The results were consistent with the theoretical predictions. The Gradflex experiment showed that in the absence of gravity fluctuations grow as large as the size of the container with the liquids. Analysis also showed that the amplitude of the fluctuations greatly increased. The results are an important step ahead in our understanding of the natural world –how systems that are not in equilibrium behave, such as mixed fluids.