In article <520da6d1$0$30000$c3e8da3$54964...@news.astraweb.com>, Steven D'Aprano <steve+comp.lang.pyt...@pearwood.info> wrote:
> On Thu, 15 Aug 2013 16:43:41 +0100, Chris Angelico wrote: > > > A mole is as much a number (6e23) as the light year is a number > > (9.5e15). > > Not quite. A mole (abbreviation: mol) is a name for a specific number, > like couple (2) or dozen (12) or gross (144), only much bigger: 6.02e23. > And I can't believe I still remember that value :-) I remember it as 6.022e23 :-) In my high school chemistry class, there was a wooden cube, about 1/2 meter on a side, sitting on the lecture desk in the front of the room. The only writing on it was "6.022 x 10^23". It sat there all year. The volume of the cube was that of 1 mole of an ideal gas at STP. > A light-year, on the other hand, is a dimensional quantity. Whereas mole > is dimensionless, light-year has dimensions of Length, and therefore the > value depends on the units you measure in: > > 1 light-year: > > = 3.724697e+17 inches > = 0.30660139 parsec > = 9.4607305e+12 kilometres Hold your hands out in front of you, palms facing towards each other, one shoulder-width apart. That distance is about one light-nanosecond. -- http://mail.python.org/mailman/listinfo/python-list
