mega and giga? Ronna and Quetta are the new hot shit

“Mega” – the word derived from the Greek μέγας (megas = “big”) has been used colloquially for decades, especially among younger people. It usually serves as a pre-reinforcing element, as an enhancement to the once-popular “super”. However, like the slightly less inflationary used “giga”, “mega” is also a prefix for units of measurement in the International System of Units (SI), such as megabytes or megatons. Here the prefix means “a million”.

In addition to the more famous of these prefixes – for example “Hekto”, “Kilo” or “Tera” – there are others that almost no one outside of the scientific disciplines knows: who knows what “Zetta” or “Yotta” means? Incidentally, this applies not only to the area of ​​the very large, but also to that of the very small: here the terms “Zepto” and “Yokto” can be found mirrored.

Until now “Yotta” and “Yokto” – in big and small – have been the end of the road. But as of last Friday, there are two new prefixes on both ends of the spectrum effective immediately: “Ronna” and “Quetta” or “Ronto” and “Quecto”. This was decided by experts from 64 countries at the General Conference on Weights and Measures in Versailles, which takes place every four years. It is the first time since 1991 that new prefixes have been defined. The additions are based on a suggestion from Richard Brown, head of the metrology department at the UK’s National Physics Laboratory.

But what do these fairly new neologisms mean? “Ronna” stands for 10²⁷ (a quadrillion; a 1 followed by 27 zeros) and “Quetta” for 10³⁰ (a trillion; a 1 followed by 30 zeros). On the other end of the spectrum, “Ronto” means 10^-27 (1 quadrillionth) and «Quekto» 10^-30 (1 trillionth). These are unimaginably large or small numbers that should play no part in our daily lives. For scientists, however, they have a practical use: they make it easier to name things.

This is shown by the examples Brown gave: The mass of an electron corresponds to a rontogram, ie 0,000,000,000,000,000,000,000,000,001 grams And one byte of data increases the mass of a smartphone by 1 mercury. In contrast, the planet Jupiter, by far the largest planet in our solar system, has a mass of two quettagrams (2 quintillion grams), while Earth has a mass of just under 6 ronnagrams (6 quadrillion grams). And the diameter of the visible universe, according to Brown, is “only one ronnameter” (that’s about 93,000,000,000 light years, where a light year is about 9,460,000,000,000,000 meters).

In the past, it was more the chemists who pushed for the introduction of new prefixes in metrology, as they had to do with, for example, Avogadro’s constant, which indicates how many particles are in a mole (6 • 10²³). According to Brown, data science is the driving force today, reports the scientific journal Nature. For example, in the 2030s, humanity will produce about one yottabyte of data per year – that’s 10²⁴ Byte. Burning this amount of data onto DVDs would result in a stack of these discs stretching from Earth to Mars. Currently, the amount of data generated annually worldwide has already reached the zettabyte (1 thousandth of a yottabyte) limit.

At the other end of the scale — i.e. “Ronto” and “Quecto” — the need for new prefixes isn’t as great right now, Georgette Macdonald, director general of the Canadian Metrology Research Center, told the science journal. Here it is mainly quantum and particle physics that may need new prefixes. Nevertheless, it makes sense to introduce corresponding terms at the smaller end of the scale: “We’re not really sure we’re measuring anything in this area. But it’s better if the scale is balanced and the prefixes are in a consistent relationship to each other,” Macdonald said.

The need for new prefixes led to informal proposals for the 10th²⁷ started to assert themselves, like “Hella” or “Bronto”. As a metrologist, this shocked him, Brown told Nature, because these were completely unofficial terms. But the main problem with these wild terms is that their symbols (h and b) are already used for other units or prefixes. For example, H stands for “hekto” (10e²) and H is “Henry”, the SI unit of inductance.

Brown therefore looked for prefixes that start with a letter that is not yet used as a symbol. The last possible candidates were r and R and q and Q. Brown got the names with these initials by following the rule that the prefixes for large numbers end in “a” (e.g. “Tera”), while those for small numbers end on “o” (e.g. “Femto” ).

At the same time, the names should resemble Greek or Latin numerals as much as possible. “Ronna” and “Quetta” therefore sound a bit like the Greek words for nine and ten, ἐννέα («ennea») and δέκα («deka»). “Quecca”, which Brown initially preferred, was dropped because it resembles a Portuguese swear word.

It is still unclear what will happen when a field of science reaches the order of 10³³ reaches. Since there are no more free letters in the Latin alphabet, one will have to switch to other alphabets or consider combinations such as kiloquetta (kQ). Brown isn’t worried. “We probably won’t have to worry about that for a long time,” he noted. (i.e)