I'm Emily Conover, physics writer for Science News. Scientists have redefined the kilogram, basing it on fundamental constants of nature. Why? How? What's that mean? AMA!
I’m Emily Conover, a journalist at Science News magazine. I have a PhD in physics from the University of Chicago and have been reporting on scientific research for four years. The mass of a kilogram is determined by a special hunk of metal, kept under lock and key in France. Today, scientists officially agreed to do away with that standard. Instead, beginning on May 20, 2019, a kilogram will be defined by a fundamental constant known as Planck’s constant. Three other units will also change at the same time: the kelvin (the unit of temperature), ampere (unit of electric current), and mole (unit for the amount of substance). I’ve been covering this topic since 2016, when I wrote a feature article on the upcoming change. What does this new system of measurement mean for science and for the way we make measurements? I'll be answering your questions from 11 a.m. Eastern to noon Eastern. AMA!
(For context, here's my 2016 feature: https://www.sciencenews.org/article/units-measure-are-getting-fundamental-upgrade
And here's the news from today https://www.sciencenews.org/article/official-redefining-kilogram-units-measurement)
Edit: Okay I'm signing off now. Thanks for all your questions!