Scientists Killed the Kilogram in 2018, Long Live the Kilogram

It's been reborn as something much better: the kilogram.

A kilogram is a kilogram, right? … right? Well, yes and no. For over a century, the kilogram has been defined by a cylinder of platinum and iridium housed in a super secure vault in Paris. Copies of it, dispersed throughout the world, have been periodically measured against this cylinder — called the International Prototype Kilogram — to make sure that international trade, science, and technology communities are all on the same page regarding this basic unit of measurement. If this sounds outdated, don’t worry: That old system is dead. In the fall of 2018, the international scientific community voted to brush the IPK aside in favor of a standard mass measurement that’s more universal. Now, thanks to the hard work of physicists, the kilogram has a new standard, one that can’t be stolen, broken, or dropped.

As Inverse reported in November, the National Institute of Standards and Technology in the US and the National Physical Laboratory in England have been hard at work on a device called the Kibble balance, which will render the IPK obsolete. And on November 16, at the General Conference on Weights and Measures in Versailles, France, representatives from 58 member countries voted unanimously to set a new standard for the kilogram. Henceforth, the kilogram will be defined in terms of the amount of electromagnetic force in an object, as measured by the Kibble Balance, which is described in the video above.

This is #12 on Inverse’s list of the 25 Most WTF stories of 2018.

A replica of the IPK, which is no longer the standard for the kilogram.


This change in how the kilogram is defined is part of a broader effort in the scientific world to make units of measurement more universal. That is, rather than being defined by some object like the IPK, they should be defined by a constant that is the same anywhere in the universe. For instance, the meter used to be defined by a platinum bar with two marks in it, an object much like the IPK. But in 1983, that bar signifying an official meter was retired in favor of a new measurement: the distance a light beam travels in 1/299,792,458 seconds. This might sound unnecessarily complicated, but thanks to this change, a meter is a meter no matter where you are, no matter whether you have a measuring tape. By transitioning from artifacts to universal constants, scientists get further from the possibility for error.

And that’s a really good thing when it comes to the IPK, because over the years, it has slowly been losing mass. That’s bad news for such a scientifically crucial artifact, so the death of the kilogram couldn’t have come at a better time.

Long live the new kilogram.

As 2018 draws to a close, Inverse is counting down the 25 stories that made us go WTF. Some are gross, some are amazing, and some are just, well, WTF. In our ranking from least to most WTF, this has been #12. Read the original article here.

Watch the full 25 WTF countdown in the video below.

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