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Latest Planck constant Stories

2012-02-20 20:26:16

New research, published by the National Physical Laboratory (NPL), takes a significant step towards changing the international definition of the kilogram — which is currently based on a lump of platinum-iridium kept in Paris. NPL has produced technology capable of accurate measurements of Planck's constant, the final piece of the puzzle in moving from a physical object to a kilogram based on fundamental constants of nature. The techniques are described in a paper published in Metrologia...

2011-07-20 13:13:59

The electromagnetic force has gotten a little stronger, gravity a little weaker, and the size of the smallest "quantum" of energy is now known a little better. The National Institute of Standards and Technology (NIST) has posted the latest internationally recommended values of the fundamental constants of nature. The constants, which range from relatively famous (the speed of light) to the fairly obscure (Wien frequency displacement law constant) are adjusted every four years in response to...

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2011-01-24 09:35:00

Scientists are close to establishing a non-physical definition of the kilogram--the last remaining base unit in the International System of Units (SI) still defined by an existing object--after it was revealed that the prototype used to establish the measurement is shrinking. That prototype, which is a cylinder of platinum-iridium housed at the International Bureau of Measurements (BIPM) in France, has gotten approximately 50 micrograms (0.0000017 ounces) smaller over the past 100 or so...

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2010-10-27 12:37:27

Taking the first steps of what would be a major historical advance in the science of measurement, the National Institute of Standards and Technology (NIST) is participating in a worldwide effort to recommend major revisions to the International System of Units (SI), the modern metric system that is the basis of global measurements in commerce, science and other aspects of everyday life. The new SI, which would be based on seven constants of nature, would enable researchers around the world to...

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2010-07-13 08:26:09

An international team measures the charge radius of the hydrogen nucleus and stumbles across some mysteries of physics Big problems sometimes come in small packages. The problem with which physicists must now concern themselves measures a mere 0.0350 millionth of a millionth of a millimeter. This is precisely the difference between the new, smaller, dimension of the proton, the nucleus of the hydrogen atom, and the value which has been assumed so far. Instead of 0.8768 femtometers it measures...

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2005-12-20 08:25:07

An international team of astronomers has looked at something very big -- a distant galaxy -- to study the behavior of things very small -- atoms and molecules -- to gain vital clues about the fundamental nature of our entire Universe. The team used the National Science Foundation's Robert C. Byrd Green Bank Telescope (GBT) to test whether the laws of nature have changed over vast spans of cosmic time. "The fundamental constants of physics are expected to remain fixed across space and time;...