wrote:
> isn't kilometer a bit, well, easy? Upping the stakes a bit, you could ask
> the question:
>
> "What is blue?"
There's a definition of that you could use involving the effect of the
reflect or emitted or transmitted light upon a human eye, *on average*
(over the entire human race) causing more than a certain amount of
stimulation to the blue receptor compared to the other receptors...
Which could be approximated in terms of stating that at least a certain
percentage of the radiant energy within the visible spectrum is within
the "blue" bit of it.
> So, a kilometer could be 1000 arbitrarily defined units.
Or indeed just one arbitrarily defined unit ;-)
>
> Roger.
>
ABS
