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Kilobytes, megabytes, gigabytes... How can bigger data be described? Millimeters, microns, nanometers... how small a number can exhaust the microcosm? The International System of Units recently introduced 4 new prefixes used to form decimal multiples and fractional units, respectively expanding the counting units of the largest and smallest numbers to meet the needs of scientific progress and data storage.

**Earth weighs 6ronn grams**

According to a report by National Public Radio on the 19th, the four new prefixes are ronna, quetta, ronto and quecto. Among them, ronna means that there are 27 zeros after the number, and quetta means that there are 30 zeros after the number. ronto and quecto are used to represent extremely small numbers, respectively representing 27 zeros and 30 zeros after the decimal point.

On the 18th, the 27th International Conference on Weights and Measures held in Paris, France, adopted the suggestion of Richard Brown, head of metrology at the National Physical Laboratory of the United Kingdom, to introduce the above four prefixes to the International System of Units with immediate effect. This is the first addition to the International System of Units since 1991.

Brown told the Associated Press reporter that people are already familiar with the prefix "milli" in units such as "millimeter" and "mg", and the newly added 4 unit prefixes can represent the largest and smallest data that have been measured so far.

Previously, the prefix of the largest unit in the International System of Units was "Yao" (yotta), which represented 24 zeros after the number. Previously, the mass of the earth could be described as about 6000 yokes, and after the introduction of ronna, it can be described as about 6 ronnagrams (ronnagram); the mass of the sun can be described as about 2 billion yokes, and now it can be described as about 2000 quettagrams (quettagram).

**Electron weighs 1 rontog**

The British National Physical Laboratory issued a statement saying that the development of data science and digital storage has already used the largest counting unit in the International System of Units, so it is necessary to introduce a new unit prefix. The newly introduced unit prefixes will meet future counting needs as they arise, Brown said. The International Data Corporation, an American market research organization, predicts that by 2025, the world will generate 175 zettabytes of data. Zetta was previously the second largest unit prefix, denoting 21 zeros after the number.

The newly added unit prefixes ronto and quecto, which represent extremely small numbers, can meet the research needs of quantum science and particle physics. Before "yocto" was the prefix of the smallest unit, the mass of an electron can be described as about 0.001 yoctogram (yoctogram), but now it can be described as 1 rontogram (rontogram).

Brown said that ronna and quetta are abbreviated as R and Q respectively, while ronna and quecto are abbreviated as r and q respectively.

He said that ronna, quetta, ronto, and quecto were chosen as the new unit prefixes because only the letters r and q have not been used as unit prefixes, and the pronunciation of these 4 words sounds like Greek pronunciation and meets the requirements of large units. The convention that prefixes end with a and small unit prefixes end with o.

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