The metal cylinder, which has been the international benchmark of one kilogram for 118 years and has been kept under three locks in France, is mysteriously losing weight, the Associated Press reported
According to the employee of the International Bureau of Weights and Measures Richard Davis (Richard Davis), the standard weighs on average 50 micrograms less than the cylinders that are brought for verification from other countries.
“The mystery is that they were all made of the same material, many of them at the same time period and were stored in the same conditions. And, nevertheless, their masses are gradually diverging. We really don't have a good explanation for this,”Davis said.
The standard kilogram is kept in a castle in the city of Sèvres near Paris. It is taken out of storage almost exclusively for comparison with other cylinders.
"It is unclear whether the original has become lighter or the samples from other countries have become heavier," says Michael Borys, senior researcher at the German National Institute for Measures in Braunschweig.
"However, by definition, only the original accurately represents the kilogram," the researcher notes.
In 1889, this cylinder was made in accordance with the latest achievements of science: it is an alloy of platinum and iridium 3.9 centimeters in height and in diameter.
According to the newspaper, an advisory group will meet in Paris in November to determine an alternative to the metal standard of the kilogram, as well as other measures: the kelvin, which serves as a unit for measuring temperature, and the mole, in which the amount of substance is expressed. Benchmarks will be based on more accurate calculations, and all states will have to accept these changes.
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At the same time, as scientists note, the changes will not affect everyday life in any way. “It won't mean anything to ordinary people. A kilogram will remain a kilogram,”says Davis.
However, for scientists, who in their work start from the value of the kilogram, the floating unit of measurement is a big hindrance, which is reflected in the results of precision work and, in particular, in the production of electricity. “They are uncomfortable with using a definition of a kilogram that is based on something,” Davis said.
Many standards have been improved over time. In particular, the meter, once modeled on the notches on a block, is far from the modern high-tech standard, measured by the distance light travels in a vacuum.
One of the contenders for the role of a new standard for the kilogram is a ball created from a silicon-28 isotope crystal - such a standard would include atoms of the same type and would have a fixed mass.
However, according to Davis, scientists "must certainly find the best solution."