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UNDERNEWS

Undernews is the online report of the Progressive Review, edited by Sam Smith, who covered Washington during all or part of one quarter of America's presidencies and edited alternative journals since 1964. The Review, which has been on the web since 1995, is now published from Freeport, Maine. See main page for full contents

August 20, 2009

THINGS WE HADN'T STARTED WORRYING ABOUT YET

NPR - More than a century ago, a small metal cylinder was forged in London and sent to a leafy suburb of Paris. The cylinder was about the size of a salt shaker and made of an alloy of platinum and iridium, an advanced material at the time. In Paris, scientists polished and weighed it carefully, until they determined that it was exactly one kilogram, around 2.2 pounds. Then, by international treaty, they declared it to be the international standard. . . As it stands, the entire world's system of measurement hinges on the cylinder. If it is dropped, scratched or otherwise defaced, it would cause a global problem. "If somebody sneezed on that kilogram standard, all the weights in the world would be instantly wrong," says Richard Steiner, a physicist at the National Institute of Standards and Technology in Gaithersburg, Md. . . The official kilogram is kept locked inside a secured vault at the International Bureau of Weights and Measures near Paris. Scientists are so paranoid that they've only taken it out on three occasions: in 1889, 1946 and 1989. Each time, they've compared it to a set of copies. In 1889, the copies and the kilogram weighed the same, but by 1989, they had drifted apart. Based on the data, the kilogram appears to weigh slightly less than the copies. The real crux of this problem is that it's impossible to tell what has changed over the past 120 years. The copies may have grown heavier over time by absorbing air molecules. But it's equally possible that the kilogram is getting lighter. Periodic washings, for example, may have removed microscopic quantities of metal from its surface.

1 Comments:

Anonymous Anonymous said...

what is wisdom in the man's eyes is foolishness in God'eyes.

What a perfect illustration of that with this article...excellent...

Sorry for my poor english.Forgive me.

November 16, 2009 6:43 AM  

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