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Scientists to Reboot the Kilogram


This is a copy of the lump of metal which since 1879 has been single-handedly responsible for telling the world exactly how much a kilogram weighs.


But many of the world's scientists worry that this metal cylinder currently stored in a French lab carries too much weight unintended.When you just get it out of the vault, it's slightly dirty.But the whole process of cleaning or handling or using the mass can change its mass.So it's not the most, not the best way perhaps of defining mass.It's been very good for the last 130 years, but it's also a single point of failure in our entire mass system.


In a vote this Friday, scientists from the General Conference on Weights and Measures are expected to vote unanimously to say goodbye to that kilogram weight.They will adopt a new measuring system based on universal constants,the scientific term for things that never change, like gravity or the speed of light. A kilogram will still be a kilogram, but like the speed of light, it can't ever change.There will be absolutely no change whatsoever, and it's taken an enormous amount of effort and agreement to get to that point.


So why do it? Because no matter how precise the measurements of that lump of metal in France,its weight has changed ever so slightly over time.It's never perfect.And when engineers deal with weight on a smaller and smaller scale,that little imperfection becomes a huge imperfection called an uncertainty in scientific terms.And big uncertainties can make things like the tiny microchip in your new phone less precise and less efficient.We need to be met...to be able to measure at different scales because the uncertainties built up very, very quickly.The new system means no more uncertainty.And scientists say that will help clear the way for new more advanced technology in the future.


Kevin Enix VOA News

美国之音记者Kevin Enix报道。

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