The discussion centers around the speed of surface waves in different liquids, specifically comparing water, liquid mercury, and liquid mercury on the moon. Participants explore the relationship between liquid density, gravity, and wave speed, referencing the formula v~sqrt(g*h) where g is gravity and h is liquid depth. There is a debate on whether denser liquids lead to faster wave speeds, with some arguing that less dense liquids, like water, would allow waves to travel faster due to lower inertia. The intuitive approach suggests that while denser liquids might store more energy, they could also move more slowly due to increased inertia. Ultimately, the conversation reflects uncertainty about the effects of density and gravity on wave speed, leaving open the possibility that all scenarios could yield similar results.