Author ｜ Xu Rui
The International System of Units (SI) conference (CGPM) held on November 18 in Versailles, France, may establish new prefixes for the largest and smallest numbers globally. Currently, the suggested prefix for the largest number is ronna and queta, while the suggested prefix for the smallest number is ronto and quecto.
The International System of Units (SI) is the most widely adopted and universally recognized standard for measurement units, forming the basis for every measurement.
The internet has generated so much data that people can hardly find words to describe its scale.Image Source: Erik Isakson Photographics
In addition to defining basic units such as kilograms and meters, SI also specifies the naming conventions for large numbers. The last expansion of this naming scheme occurred in 1991. For very large numbers, when a number is followed by 21 or 24 zeros, the prefixes are zetta (1021) and yotta (1024); for very small numbers, the prefixes are zepto (10-21) and yocto (10-24).
At that time, such prefixes were rarely used, but as the amount of data generated and stored on the internet continues to grow, they have found their place. It is expected that by 2025, the total amount of data in the world will reach 175 zetta bytes.
“Many in the media have speculated about what the prefix larger than yotta byte will be,” said Richard Brown from the UK National Physical Laboratory (the UK’s national measurement standards laboratory). For example, the term bronto byte has been informally used by some to describe 1027 bytes, while Google’s unit converter has long converted 1027 bytes to hella bytes.
However, Brown pointed out that SI has already used the letters “b” and “h” as prefixes, and these informal prefixes do not conform to SI’s naming rules. Therefore, there is an urgent need to establish standard prefixes to prevent these informal prefixes from becoming too entrenched in scientific literature.
Brown helped draft a proposal for the prefixes, which CGPM member countries can raise objections to at the conference. If there are no objections, the new prefixes for numbers with 27 and 30 zeros will be ronna (1027) and queta (1030) for large numbers, and ronto (10-27) and quecto (10-30) for small numbers. However, even if they are established as international units, it may take scientists some time to adapt to them in their work.
Additionally, some scientists are skeptical about the usefulness of the new prefixes. “We tend to define our own units, which are more useful for practical research,” said Mike Merrifield, an astronomer at the University of Nottingham.
Brown believes that ronto and quecto could be used in the field of radio astronomy, for example, to measure the faint cosmic microwave background radiation. In response, Merrifield stated that astronomers already have commonly used units—non-SI Jansky.
However, Brown believes that using these standard units can better convey information.
These prefix names may seem arbitrary, but they strictly adhere to SI. The letters “R” and “q” are the only remaining letters in the English alphabet not used by other SI prefixes. Furthermore, the middle part of the new prefix words is a rough translation from Latin meaning “multiplied by how many thousands,” and the prefix names ending in “a” or “o” follow the convention that prefixes indicating “large” always end in “a” and those indicating “small” end in “o.”
As for when larger or smaller prefixes will appear, Brown believes it will be at least another 25 years.
Source: China Science Daily (2022-11-18, Page 2, International, Original Title: “The New Prefixes for ‘Largest’ and ‘Smallest’ Are Here” )
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