We live in a very large universe and we need very large units to describe it. And for this need, the institution that defined our units rushed to help by adding the prefixes ronna and quetta for things too large to be easily measured in yottas. If you want to discuss incredibly small things though, you can now use the prefixes ronto and quecto.
Although the extreme prefixes are less used, until last week the largest prefix was yotta for 10 to the 24th and the smallest was yocto (10 to the minus 24). But now the 27th General Conference on Weights and Measures, responsible for oversight of the metric system, has added two additional prefixes to each end, expanding the easily identifiable range by a million times in both directions.
Although its roots can be traced back to the French Revolution, the International System of Units (SI) units were established in 1960 with an initial range from atto to tera (10 to the minus 18 and 10 to the 18th). More prefixes were added in 1964 and 1991 as our understanding of the universe improved.
These prefixes are used for seven basic units: second, meter, (kilo)gram, ampere, kelvin, mole, and candela. However, other units not under the control of the General Conference also copied the terminology. The fact that the world is currently producing an enormous amount of data and the fact that soon yottabyte (1,000 000 000 000 000 000 000 000 bytes) will not be enough to describe it was one of the factors that motivated the expansion.
From the UK’s National Physics Laboratory, Dr. Richard Brown spearheaded the addition of new units after seeing references to brontobytes and hellabytes, which are officially unrecognized prefixes. It is crucial that the General Conference provide formal definitions so that the defined units are not used in different ways by different states. Such confusion can lead to disasters, exactly the kind that SI units are designed to avoid.
With the new prefixes, Earth now weighs six ronnagrams and the Sun two thousand Quettagrams…
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