SoylentNews is people
SoylentNews
Fundamental constants are physical quantities that are universal in nature.
...
According to a recent evaluation and update of the values of the fundamental constants by researchers at the National Institute of Standards and Technology (NIST), the uncertainties in measurements of the constants have now been reduced to such exceedingly low levels that all of the SI units can now be linked to them.
...
The latest update of the values of the fundamental constants was authored by NIST's Peter Mohr, David Newell and Barry Taylor, who lead the international Task Group on Fundamental Constants of the Committee on Data for Science and Technology (CODATA). This task group updates the values every four years. The new quantities represent the latest comprehensive adjustment of values of the constants. In the summer of 2017, the task group will perform a special update to produce the final values for four fundamental constants to be adopted in the fall of 2018 by an international body known as the General Conference on Weights and Measures (Conférence Générale des Poids et Mesures, or CGPM).
...
Examples of fundamental constants range from the magnitude of the elementary charge of a single electron or proton to the extraordinary number of particles in one mole of a substance, described by the Avogadro constant. Another example is the Planck constant, a quantity at the heart of quantum physics that will be used to redefine the kilogram as an invariant property of nature instead of a standard platinum-iridium cylinder.The evaluation and update reduce the uncertainties in both the Planck and Avogadro constants by almost four times compared to the previous evaluation, to just 12 parts per billion. These uncertainties decreased by reconciling measurements in different "watt-balance" devices around the world and new highly accurate X-ray measurements of a softball-sized sphere of silicon that is a nearly perfect crystal and is made almost entirely of the same isotope of silicon (99.9995 percent silicon-28). The update reduces the relative uncertainty by almost two times, to 0.6 parts per million, for the Boltzmann constant, which can be used to determine the amount of energy in a gas at a certain temperature.
Related reporting.
(Score: 2) by HiThere on Tuesday November 29 2016, @07:28PM
The US units are based on the old "Imperial units" that we inherited from Britain. Because the US has a large population and is relatively distant from Europe there wasn't a strong impetus to change to the metric system in most areas. Less in the US than in Britain, because Britain was closer to Europe.
This isn't to say that nativist arguments weren't used to prevent official conversion, but the real reason is that most people objected to the very idea of changing. I believe that the less common units have also dropped out. I haven't hear rods, chains, or furloughs mentioned as serious units since grade school math problems. It's also true that Imperial units tend to be more convenient to human scale than are metric units. Liter is pretty good, but what's a metric equivalent of a half-pint? But half-pint is a very convenient unit in which to consume milk. As is a pint for a teen-ager. Feet are a very convenient size for a multitude of things. Yard could easily be replaced in its uses by meter, but it fits nicely with foot, so there's a network effect. Etc.
When I'm doing scientific work I always use metric, but the units aren't generally scaled properly for human interfacing things. A 1/4 liter isn't as easy to think about, especially for a second grader, as a half-pint.
And are pixels metric? What's the metric equivalent? You need to choose your units to suit your problem.
All that said, people who grow up with the metric system seem to handle it well, so these problems are clearly only annoyances, and certainly unit scaling is much better in the metric system. But all my file cabinets are made with the assumption that I'm using letter size paper, not A4. My printer keeps trying to print on A4 when my paper is letter. This is quite annoying...but this doesn't make me want to change paper size, it makes me want to strangle the guy that wrote the driver (or possibly the driver configuration, since it didn't used to do this).
Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.