Speculation on new SI prefixes

The SI prefixes giga and tera were adopted in 1960. The prefixes exa and peta were adopted in 1975, and zetta and yotta were adopted in 1991. Following this 15-year cadence, we should have adopted a few more prefixes by now. If we ever do introduce new prefixes, what might they be?

The latest prefixes follow this pattern: the prefix for 103n is some form of the name for n in some language. The prefixes peta for 1015 and exa for 1018 come from the Greek names for five and six, and the prefixes zetta for 1021 and yotta 1024 are based on the Latin names for seven and eight. If we stick with this pattern, and stick with Latin, the prefix for 1027 should be novem or some variant, and the prefix for 1030 should be decem or some variant [1].

Maybe some day we’ll speak of novemabytes of data, or a calculation requiring novemaflops of computing. There’s not much need to speak of novemameters since the observable universe is about a yottameter across.

The mass of the sun is about 2 × 1033 grams. We could call that a couple undecimagrams. The mass of the Milky Way is about 3 × 1045 grams, or three quindedimagrams.

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[1] There’s no need for more prefixes; this post is just for fun.

4 thoughts on “Speculation on new SI prefixes”

1. A laser between 2 mirrors certainly travels that far…

2. Michael Watts

You’re suggesting prefixes that are based on the actual Latin numbers, but there are two obvious issues:

– The other extreme prefixes are not based on actual Greek or Latin in any recognizable way. The Greek prefixes for 5 and 6 would be penta- and hexa-, already in common use for 5 and 6, and the Latin words for 7 and 8 would be septem and octo, which bear almost no relationship to zetta and yotta. Neither Z nor Y can even occur in Latin; they are both indicative of Greek.

– There is already an SI prefix based on decem, it is the correctly-formed deci- prefix indicating 10^{-1}.

By these standards of “based on”, a prefix based on the Latin word “novem” would look more like “enza-” than “novema-“.

3. Nathan Hannon

If we follow the pattern of zetta/zepto and yotta/yocto, the prefixes for 10^27 and 10^-27 should be something like xova/xovo.

If we need prefixes after that, I would propose something loosely inspired by provisional names for elements: a positional system using syllables chosen more for practicality than historical consistency. After xova (X) might come, say, kilinga (kL), then kikilo (kk), kimega (kM), and so on.