Jan V. Sengers
Institute for Physical Science and Technology, University of Maryland, College Park, MD 20742
Thermal fluctuations in fluids on earth and in space
During the past few decades it has been discovered that thermally induced nonequilibrium fluctuations in fluids become macroscopically large, even when the system is far away from any hydrodynamic instability. Theoretical and experimental evidence for this phenomenon will be presented. However, these fluctuations cannot grow indefinitely since they become suppressed by gravity. To examine the effect of gravity I shall also discuss some recent experiments performed in space under the auspices of the European Space Agency. These experiments have confirmed that thermally induced nonequilibrium fluctuations in fluids in space are several orders of magnitude larger than those observed on earth.