Snowballs to soot: The clumping density of many things seems to be a standard

Particles of soot floating through the air and comets hurtling through space have at least one thing in common: 0.36. That, reports a research group, is the measure of how dense they will get under normal conditions, and it's a value that seems to be constant for similar aggregates across an impressively wide size range from nanometers to tens of meters.

Fuente : http://feeds.sciencedaily.com/~r/sciencedaily/~3/o...