[time-nuts] SI Unit Problems

Mike S mikes at flatsurface.com
Wed Apr 6 02:14:03 UTC 2011


At 09:01 PM 4/5/2011, ehydra wrote...
>the k is low but should be K to be consistent (M, G, etc).

That's historical. All of the original prefixes (from 1795) were lower 
case. When new ones extended the magnitudes (in 1960), capitalization 
was necessary to distinguish M(ega) from m(icro). They also chose to 
capitalize all higher order prefixes. Prefixes da, h, and k weren't 
capitalized to maintain backward consistency.

I suppose they could have used "me" or "ma" as the prefix for mega, 
just as d(ek)a was originally used to distinguish it from d(eci), but 
then two character prefixes (or alternate, non-conflicting ones) would 
also be needed for P(eta)/p(ico), Z(etta)/z(epto), and Y(otta)/y(octo) 
when things were extended even further.

   




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