The definition of "meter" originated in France. The length of 1 meter was originally defined as one ten thousandth of the distance from the equator of the earth to the north pole on the meridian passing through Paris, and then the international meter origin was determined. With the deepening of people's understanding of measurement, the definition of the length of meter has been revised several times.
In 20 19, CGPM revised their definition text. From May 20th, 20 19, the definition of meter was updated as follows: when the speed of light C in air is expressed by m/s, a fixed value of 299792458 was selected to define meter. Where the second is defined by the frequency Δ ν cs of cesium.
Chinese name
rice
Foreign name
Meters (UK); Meters (USA); Mettre (France)
Another name
rice
kind
unit of length
Unit symbol
m
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definition
1 m = the path length of light propagating in vacuum in 1/299 792 458 seconds. [ 13]
Development history
put forward
1688, British philosopher and priest John Wilkins put forward the necessity of decimal standard length unit system.
1675, the Italian scientist Ti Tuo Livio Bratini first used the word metro cattolico in his paper, which originated from the Greek μ? τρον καθολικ? ν(métron katholikón), which means "universal unit of measurement".
1789, after the victory of the French Revolution, the National Association ordered the Organizing Committee of the French Academy of Sciences to adopt the unified measurement system. The Committee put forward a new metric system and suggested that one tenth of the distance from the equator to the North Pole on the meridian passing through Paris (that is, one fortieth of the meridian of the earth) be used as the standard unit. They called this unit mètre, which later evolved into meter, and the Chinese translation is "Mi Tu" or "meter". 179 1 year, which was approved by the French parliament. [4] [5] [6] [7]17991210, France adopted the metric system and began to formally use it.
Meridian definition
Although the irregular surface of the earth is not a perfect sphere, France still uses this measurement result to determine the length of the standard meter. Later, it was found that the length of the first archived meter was less than that defined by meridian 1/5 mm, because the oblateness of the earth and the arc length were miscalculated. But this length is still the standard. So in the end, the circumference of the earth passing through the pole is a little more than 40 million meters (40007863 meters).
1875 On May 20th, the French government came forward, held a meeting of government representatives from 20 countries, and formally signed the metric convention, recognizing the metric system as an internationally accepted unit of measurement. At the same time, it was decided to establish the International Metrology Committee and the International Bureau of Metrology. As of June 1985 and June 10, the metric convention has 47 members. [6]
Miyuanqi
1792- 1799, led by French astronomers, made a survey of the sky from Dunkirk, France to Barcelona, Spain. 1799, according to the measurement results, a short-section platinum rod of 3.5 mm× 25 mm was made, and the distance between the two ends of the rod was set as 1 m, which was kept by the French archives, so it was also called "archival meter". This is the earliest definition of rice, and this primitive rice utensil has been kept in the French archives in Paris.