Join us for an NASC Colloquium on "Reversals of the Large-Scale Circulation in Thermal Convection" presented by Nick Moore, assistant professor of mathematics.Thermal convection, or the tendency of heat to rise and cool material to descend, often gives rise to a large-scale circulatory flow structure. It is known that the large-scale circulation (LSC) can undergo spontaneous reversals. In the atmosphere, reversals can result in a sudden change in wind direction, while in Earth’s liquid core, reversals may play a role in magnetic dipole shifts. Moore will discuss LSC reversals in the context of 2D annular thermal convection. A newly constructed model describes a range of LSC behaviors that have been observed in laboratory experiments and numerical simulations, including a state of consistent, uninterrupted circulation, a state of chaotic LSC reversals, and a paradoxical state of turbulent flow yet regular LSC reversals. Unlike heuristic models, the new model is firmly linked to first principles, and it offers new predictions for the timing of LSC reversals that are shown to agree closely with direct numerical simulations. I will briefly discuss extensions of the model, including one that accurately recovers the gross heat transport.Reception to follow in the Ho Science lower atrium.