NIST Backs Proposal for a Revamped System of Measurement Units

NIST ^ | 10/26/2010 | NIST

[Logophile]

From the linked article:

It was only about fifty years later, and twenty years after Rømer’s death, that the British astronomer James Bradley’s measurements could definitively prove that the speed of light was indeed finite; it was 1727.

The speed of light was 1727?

[kosciusko51]

That was some bad writing. However, given the proper scale for distance and time, 1727 would be the correct answer! (On a complete side note, the speed of light is 173.1 Astronomical Units/day, which is ~1/10th of 1727. Perhaps they were only off by a decimal point).

[Hootowl99]

Good point!

My again fearless and hopefully better stated opinion is that NIST would have a working master standard calibrated to say the Planck's Constant you exampled then a working (secondary) standard would be created from this master. A master standard is too precious (costs a lot!) to be handled or otherwise used to any large degree.< And, I completely confess that I forgot what the blazes unit J-s is!P> I recently bought a set of four standards for a spectrophotometer for $134 that have a NIST traceable calibration certificate that lists an absolute value for each tube plus the variability of the lot that they were prepared from. By the example above, I think these are likely a tertiary level standard. Per the manufacturer's procedures in using the standards, if the instrument reading is the calibration value plus or minus the lot variability then the spectrophotometer is functioning to manufacturer's specifications. Otherwise, maintenance service is needed for the spectrophotometer

[castlebrew]

What??!! there's 7 constants?

I thought there were only these:

1. Death

2. Taxes

3. Politicians are crooked