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>The mass of the international prototype of the kilogram m(K) is equal to 1 kg within a relative standard uncertainty equal to that of the recommended value of h at the time this Resolution was adopted, namely 1.0 × 10-8 and that in the future its value will be determined experimentally,
Is the Planck simply the most standard deviation the kilogram can stray from now?
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I wonder how much the cylinder will auction for.
I have already sent an email to the Norwegian bureau of standards to inquire about buying one of their secondary kilogram standards - presumably they'll want a couple for displays and museums, but it would make for a great letter weight. (Just hoping the secondary ones are NOT also made from platinum. That is a tad too extravagant, even for a measurement nut.) I do happen to have the previous generation time standard…
They are. They are made identically to the primary.
Has a "metric" version of time ever been proposed? Seems odd to me that we're "ok" with divisions of 12 for time but not length. I guess for science seconds are basically the only measure of time that usually matters?
24 and 60 do make sense because they are highly composite numbers: https://en.wikipedia.org/wiki/Highly_composite_number
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The real question is how many boxes will the fulfilment center place the kg in. If Amazon is anything to go by my money is on 3
OT, but this ! I recently ordered a picture frame from Amazon. It came in its packaging box, which was placed in a box by the manufacturer. That box was put in another box by Amazon and shrink wrapped to a large piece of cardboard, which was then put inside yet another box. On the surface, it seems crazy, but Amazon did manage to get it to me undamaged.
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Heinlein's "Starship Troopers" has the space marines using "kiloseconds" and "megaseconds" conversationally, and it was always tricky for me to convert those to hours and minutes in my head accurately.
Odd choices... since 1000 seconds is ~17 minutes and 1M seconds is 4.6 hours.
Really? :)
I guess the next redefinition will happen if and when there's detectable drift in "fundamental" constants?
I guess the next redefinition will happen if and when there's detectable drift in "fundamental" constants? And until then, all the metric fanbois will constantly tell you that metric is superior to imperial because its measurements are immutable. Until suddenly they are.
This is probably the dumbest thing I'll type on HN. In university I just gave up trying to understand why we even needed the Avogadro constant / mole as a fundamental constant. It still confuses me. Why have a difference between molar mass and mass? Why couldn't it just be "1" and everything else change around it?
This is massive news.
Has a "metric" version of time ever been proposed? Seems odd to me that we're "ok" with divisions of 12 for time but not length. I guess for science seconds are basically the only measure of time that usually matters?
There has been a proposal during the French Revolution with 10 hours a day, 100 minutes an hour and 100 seconds a minute. But it has only been in use for a few years beginning in 1792: https://en.wikipedia.org/wiki/Decimal_time
Our biggest revolution yet: extending the length of the day by 16%!