Tuesday, July 26, 2011

The Constants They Are A Changin': NIST Posts Latest Adjustments to Fundamental Figures

From NIST Tech Beat: July 19, 2011
Contact: Ben Stein
301-975-3097
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 the latest scientific measurements and advances. These latest values arrive on the verge of a worldwide vote this fall on a plan to redefine** the most basic units in the International System of Units (SI), such as the kilogram and ampere, exclusively in terms of the fundamental constants.
The values are determined by the Committee on Data for Science and Technology (CODATA) Task Group on Fundamental Constants,*** an international group that includes NIST members. The adjusted values reflect some significant scientific developments over the last four years.
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