"Franz Heymann" wrote in message ...
"Rick Sobie" wrote in message
news:md8Eb.745272$9l5.166726@pd7tw2no...

[snip]

Would it not be better then, to choose a unit of length,
which is in accordane with some fundamental measurement,
that is unchanging and more accurate?

Say the radius of the Hydrogen Atom at a certain temperature
- in its rest state for instance.

The Hydrogen atom does not have a sharply defined radius.
And even if it did, how would you propose to make use of it?

[snip]

Franz
[EL]
Most probably he would end up with a table of conversion from
Hatometers to meters.

Just saying the "diameter" of the hydrogen atom implies a spherical
shape, which is not so in any static reality but a dynamic one
perhaps. The variance of such would cause agony.
I prefer a standard measure of the most invariant material length wise
when temperature, pressure, humidity and gravitational field vary and
to take it as a "long form" such that atomic vibrations become
completely insignificant. Thus, rather than finding the shortest
length to take as a reference, I would prefer the shank which is about
180 cm long to be a standard measure and extract all other units
accordingly.

But they are all arbitrations so replacing one by another makes no big
difference really.

EL