Noclevername,

One can measure the density of air without having the slightest idea of the
atmosphere's size.

I can determine whether the density of an object is greater or less than
the density of water just by tossing it into some water and seeing whether
it sinks or floats. This isn't an option with the Universe, of course...

-- Jeff, in Minneapolis

__________________
http://www.FreeMars.org/jeff/

"The other planets?
Well, they just happen to be there, but the point of rockets is to explore them!"
-- Kai Yeves