A common way to compute density is, of course, to take the ratio of an object's mass to its volume. But other types of densities exist, such as the resistance of somebody's brain to the imparting of common sense.
Neil deGrasse TysonThat's the point, to get the people who wouldn't otherwise think to eavesdrop on a conversation that involves science.
Neil deGrasse TysonOn Venus you could cook a 16-inch pepperoni pizza in seven seconds, just by holding it out to the air. (Yes, I did the math.)
Neil deGrasse Tyson