Le Grand K (2018) | Hacker News Reader

Le Grand K (2018)

atlasobscura.com

23 pointsgeox12 comments

This is how objective fact is made objective: comparison. When I say 'The Eiffel Tower in in Paris, France', this is an undeniable and objective fact. You can't refute it, unless you compare it to another statement: 'The Eiffel Tower is in Berlin, Germany'. It could be. The tower was probably deconstructed and shipped in parts and re-assembled there. The only way to ascertain this counter fact is to go there and prove it, comparing your facts against each other.

> ”Rather than rely on a platinum cylinder in a bell jar in Paris, eggheads in the world of measurements decided to anchor the future kilogram to Planck’s constant. This is a fixed quantity tied in with E=MC2 and quantum theory, specifying the amount of energy carried by a single particle of light, or photon. And that’s just the most extremely simplified version.”

Can someone provide a not-so-simplified version that is still understandable by a layman of the current definition of a kilogram?

Another comment mentioned it but the instrument used has a decently detailed Wikipedia page:

https://en.wikipedia.org/wiki/Kibble_balance

The name and appearance might make you think it's some sort of flux capacitor for dogs but that is apparently not its (primary) purpose.

That's some deeply unfulfilled nominative determinism potential.

edit: unless kibble is cognate to quibble, and precision metrology is the ultimate form of quibbling?

Looks like the etymology of 'kibble' is unknown, much like the etymology of 'dog' so the whole thing is definitely suspicious.

https://www.etymonline.com/search?q=kibble

This is THE explanation.

It's long, but it's AMAZING!

https://www.youtube.com/watch?v=KBZD3tFny_E

I think that was a premature decision we'll eventually have to reverse. Just as fixing the speed of light, things might not be as constant as current theory states it is.

What would you do instead? The silicon sphere idea? It's not like hauling around physical kilograms is going to be any better.

Veritasium (Derick, who I've met personally) does a fantastic job on these fundamental science subjects. Le Grande K was the definition of the kilogram. Derick explains the question at hand, how Plancks constant is now used.

Derick's quality is supreme & he is always very careful and confident about claims.

https://www.youtube.com/watch?v=Oo0jm1PPRuo

Replicated by Adam Savage (from "Mythbusters" and overall maker genius) here: [1]. Haven't had time to see it yet, it's fairly new (posted 12 days ago).

[1]: https://www.youtube.com/watch?v=TW1NuVmCCaw

I know the kibble balance is objectively superior but I was really rooting for the Avogadro project.

I heard the explanation that one was from physics and one was from chemistry.

And they were both important to get the error bars low enough so they could move over with confidence.

See https://youtu.be/KBZD3tFny_E?si=VyqjpainWVgbY_NF

Reply on news.ycombinator.com