A massive change: Nations redefine the kilogram

[mahatmakanejeeves]

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Say Au Revoir To That Hunk Of Metal In France That Has Defined The Kilogram

Sorry, Roland99; I didn't see it.

Dave Weigel Retweeted

Are you ready to be inspired .... by measurement?

Tomorrow, people from around the globe will come together to *agree* on something, even though it is hard, even though it is costly, because it reflects a fundamental fact about the universe

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Don't be alarmed by the scary jargon and casual use of scientific notation -- this is a story for all of humanity. It's a tale about how we built our modern world, and how, by constantly seeking to understand nature, scientists hope to help improve it:

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This is truly one of my favorite stories in science. I'm so glad I got to write about it, and really lucky to have an editor like @laurahelmuth who will champion its importance.

Will I be waking up at 4am to watch the vote live streamed? OF COURSE.

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Where is the link to the live stream?!

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Oh, good point!

It’s here: https://www.bipm.org/en/the-si/

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A massive change: Nations redefine the kilogram

By Sarah Kaplan November 15 at 7:27 PM

Humanity just made a weighty decision. On Friday, representatives of more than 60 nations, gathered in Versailles, France, approved a new definition for the kilogram.

Since the 19th century, scientists have based their definition of the fundamental unit of mass on a physical object — a shining platinum iridium cylinder stored in a locked vault in the bowels of the International Bureau of Weights and Measures (BIPM) in Sevres, France. A kilogram was equal to the heft of this aging hunk of metal, and this cylinder, by definition, weighed exactly a kilogram. If the cylinder changed, even a little bit, then the entire global system of measurement had to change, too.

With Friday’s vote, scientists redefined the kilogram for the 21st century by tying it to a fundamental feature of the universe — a small, strange figure from quantum physics known as Planck’s constant, which describes the smallest possible unit of energy.

Thanks to Albert Einstein’s revelation that energy and mass are related, determining exactly how much energy is in that unit can let scientists define mass in terms of Planck’s constant — a value that should hold up across space and time — rather than relying on an inconstant metal cylinder. (Mass determines something’s weight, and for most purposes mass and weight are interchangeable.) ... The redefinition is the result of a decades-long, worldwide quest to measure Planck’s constant precisely enough that the number would stand up to scientific scrutiny.
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Sarah Kaplan is a science reporter covering news from around the nation and across the universe. She previously worked overnights on The Washington Post's Morning Mix team. Follow https://twitter.com/sarahkaplan48

[defacto7]

1. A new way to combat inflation.

A larger measure for the same price.