◆ The International System of Units (SI) has recently introduced four new prefixes for constructing decimal multiples and fractional units, expanding the counting units for both the largest and smallest numbers to meet the demands of scientific advancement and the increasing volume of data storage:
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ronna represents a number followed by 27 zeros
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quetta represents a number followed by 30 zeros
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ronto represents a decimal followed by 27 zeros
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quecto represents a decimal followed by 30 zeros
◆ Previously, the mass of the Earth could be described as approximately 6000 yottagrams, but with the introduction of ronna, it can now be described as approximately 6 ronna grams; the mass of the Sun could be described as about 2 billion yottagrams, and now it can be described as approximately 2000 quetta grams.
According to Xinhua News Agency in Beijing on November 20, how can larger data be described? Millimeters, micrometers, nanometers… how small can numbers get to exhaust the microscopic world? The International System of Units has recently introduced four new prefixes for constructing decimal multiples and fractional units, expanding the counting units for both the largest and smallest numbers to meet the demands of scientific advancement and the increasing volume of data storage.
This image released by NASA on July 23, 2015, shows Earth (left) and the exoplanet Kepler-452b. Xinhua News Agency provided this image.
According to a report by National Public Radio on the 19th, the four new prefixes are ronna, quetta, ronto, and quecto. Among them, ronna represents a number followed by 27 zeros, and quetta represents a number followed by 30 zeros. Ronto and quecto are used to represent extremely small numbers, representing a decimal followed by 27 zeros and 30 zeros, respectively.
On the 18th, at the 27th International Conference on Weights and Measures held in Paris, the suggestion by Richard Brown, head of the National Physical Laboratory in the UK, to introduce these four prefixes into the International System of Units was adopted and took effect immediately. This is the first addition to the International System of Units since 1991.
Brown told Associated Press reporters that people are already familiar with prefixes like “milli” in units such as millimeters and milligrams, and the four newly added prefixes can represent the largest and smallest data that have been measured so far.
Previously, the largest unit prefix in the International System of Units was “yotta” (y), representing a number followed by 24 zeros. Previously, the mass of the Earth could be described as approximately 6000 yottagrams, but with the introduction of ronna, it can now be described as approximately 6 ronna grams (ronnagram); the mass of the Sun could be described as about 2 billion yottagrams, and now it can be described as approximately 2000 quetta grams (quettagram).
This image taken on October 16, 2018, shows the “Sunway TaihuLight” supercomputer installed at the National Supercomputing Center in Wuxi. Photo by Xinhua News Agency reporter Li Bo.
The UK National Physical Laboratory stated that with the development of data science and digital storage, the existing largest counting units in the International System of Units have been used, making it necessary to introduce new unit prefixes. Brown said the newly introduced unit prefixes will meet future counting needs. The American market research firm International Data Corporation predicts that by 2025, the world will generate 175 zettabytes of data. Zetta (z) is the previously second-largest unit prefix, representing a number followed by 21 zeros.
The newly added unit prefixes ronto and quecto for representing extremely small numbers will meet the research needs of quantum science and particle physics. Previously, “yocto” (y) was the smallest unit prefix, and the mass of an electron could be described as approximately 0.001 yoctograms, but now it can be described as 1 ronto gram (rontogram).
Brown stated that ronna and quetta are abbreviated as R and Q, while ronto and quecto are abbreviated as r and q.
He explained that the reason for choosing ronna, quetta, ronto, and quecto as new unit prefixes is that only the letters r and q have not been used as unit prefixes, and these four words sound like Greek pronunciations, adhering to the convention that large unit prefixes end with ‘a’ and small unit prefixes end with ‘o’.(Yuan Yuan)
Chief Editor | Shi XiangzhouEditor | Yang YueEditor | Yu Qianhuan
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