Content-Type: text/plain; charset=ISO-8859-1 -------- In message <50fef6db.4020...@xtra.co.nz>, Bruce Griffiths writes:
>But can the number and type of atoms in such a standard be counted? >Otherwise its not a primary standard. Yes. If you arrange them into a perfect sphere, you can measure the crystal-grid spacing very precisely with x-rays, and the diameter even more precisely with lasers. Interestingly, this experiment may also become the first time we ever needed to know PI better than 355/113 outside abstract mathematics. My friends in metrology all bet on the watt-balance supplying the new mass definition, rather than the quartz-ball, simply because they are so much easier to construct. The isotope-separation is really a killer. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
