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Earth now weighs six ronnagrams: New metric prefixes voted in

247 points| leephillips | 3 years ago |phys.org | reply

203 comments

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[+] illys|3 years ago|reply
Pretty nice table here: https://en.wikipedia.org/wiki/Metric_prefix

"(...) he had the idea for the update when he saw media reports using unsanctioned prefixes for data storage such as brontobytes and hellabytes. (...)" and "The only letters that were not used for other units or other symbols were R and Q"

So it seems the new prefixes are partly initiated by the exponential computer storage needs rather than scientific needs. So they might need to move again soon. However the SI has exhausted the available stock of letters. Maybe Greek letters next time like micro for 10^-6.

Anyway does it really matter for IT people? I have seen so many people mixing up bit and byte, milli- and mega- as well. There are countless usages of mb all over the Internet to express MB.

[+] iquerno|3 years ago|reply
The only use cases I have seen for units larger than 'petabyte' are those representing the maximum allowed file sizes for ZFS, Btrfs and such. I also don't see a point in inventing more prefixes so that statisticians don't have to use scientific notation for large numbers. What use is that? How many people know how much a yottabyte is? If they need to Google the answer, that defeats the point.

1e12 terabytes seems easier to digest than 1 whatever-the-hell-,-I-don't-know-what-this-unit-is-meant-to-represent-byte. Not to mention, easier to read.

[+] gregmac|3 years ago|reply
Do we need to have a single letter? Is it acceptable to combine prefixes?

Eg: 1 QB (quettabyte) == 1,000,000 YB (yottabytes) == 1 MYB (mega-yottabyte)

Without the new prefixes, we could have gone to 1 YYB (1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000, or 10^48 bytes)

[+] Asraelite|3 years ago|reply
Does anyone know why they chose "ronna" instead of "renna"? It should be r + ennea (Greek for nine), so where does the "o" come from?

Every prefix up until now has been consistent about the first vowel mirroring the Greek word:

  tetra -> tera
  penta -> peta
  hex -> exa
  hepta -> zetta
  okto -> yotta
[+] labster|3 years ago|reply
Uppercase MB is megabytes, lowercase mb is millibars. Both can go through a series of tubes, but millibars are also useful in dump trucks, to make the wheels go round and round.
[+] troelsSteegin|3 years ago|reply
Via https://www.nature.com/articles/d41586-022-03747-9, "Extreme numbers get new names":

The prefixes ronna and quetta represent 10^27 and 10^30, and ronto and quecto signify 10^−27 and 10^−30. Earth weighs around one ronnagram, and an electron’s mass is about one quectogram.

This is the first update to the prefix system since 1991, when the organization added zetta (10^21), zepto (10^−21), yotta (10^24) and yocto (10^−24).

[+] rikkipitt|3 years ago|reply
The way I remember Earth's approximate mass is the fact it's 10 times Avogadro's number in kg.

My physics teacher always had a great way of drilling in these tidbits.

[+] opwieurposiu|3 years ago|reply
Yes and the circumference of the earth is about 40 million meters. This is because a meter was originally supposed to be 1/10E6 the distance from the equator to the north pole through Paris.
[+] mncharity|3 years ago|reply
> The way I remember Earth's approximate mass is

For me, it's: Earth is a blue marble - in "Mega-view" (Mm zoomed to mm) - with a diameter of a baker's dozen Megameters. The volume of a ball is one half of its enclosing box, so that's ~(1E7)^3 or 1E21 m^3. Earth is rock (3 Mg/m^3) and iron (8 Mg/m^3) and averages 5 Mg/m^3. Or just bracket it - water,lead,gold is ~ 1,10,20 Mg/m^3). Giving an Earth mass of 5E24 kg. Actual value 6E24 kg. Brackets of water and lead give 1E24 to 11E24 kg.

> a great way of drilling in these tidbits

For me it's: Arm-sized, hand-sized, fingernail-sized, and "tiny"-sized, are 1000, 100, 10, and 1 mm. Zooming these by 1000^n gives scale-model "views". Mega-view with planet balls, kilo-view with cities in your palm, meter-view with buildings in hand, micro-view with red blood cell M&M's (yum), nano-view with virus balls (chewy shell, stringy inside), pico-view with H2O bumpy basketballs, femto-view with nuclei marbles. It's easier to remember how big things are, once they're toy-sized, and you've handled and played with them.

Just something I crafted years back. Resulting videos didn't seem to user test well. I was set to dust it off, doing rapid iterative development over gorilla street usability testing... in Spring 2020. Ah well.

[+] vitiral|3 years ago|reply
Take ten moles of earth, fire, wind and water. What do you have? Captain planet!
[+] zem|3 years ago|reply
nice. filing it alongside the pi * 10^7 seconds in a year
[+] Aardwolf|3 years ago|reply
I guess that gives us new binary prefixes as well, we can now express data sizes in robibit, quebibit, robibyte and quebibyte!
[+] joeyh|3 years ago|reply
Will need an update to IEC 80000-13 won't it? Or does the standard define a formula to derive the names from the metric prefixes?
[+] arunc|3 years ago|reply
And here in US, we are stuck with imperial units like it was 1800s: oz, pounds, inches, feet, miles, etc for all common usage. When a foreigner visits here, the first thing they realize is how US has truly siloed itself from the rest of the world.
[+] IvyMike|3 years ago|reply
A couple of decades and several jobs ago I wrote some file transfer code that displayed human readable sizes, and as a joke to myself, I included prefixes up to yottabytes. Careful readers of the code should have flagged this as impossible because anything above exa- is impossible using 64 bits, but it got thru review and as far as I know the code lives on to this day. I'm hoping someone adds these new prefixes.
[+] NKosmatos|3 years ago|reply
From https://en.wikipedia.org/wiki/Metric_system :

“The SI has been adopted as the official system of weights and measures by all nations in the world except for Myanmar, Liberia, and the United States.”

[+] anonporridge|3 years ago|reply
Indirectly false.

Even though we don't use metric directly in most cases in the US, the US customary units have long been rebased to be defined by metric units.

Inches and pounds are just centimeters and newtons walking around in a whacky outfit.

[+] rootusrootus|3 years ago|reply
And the UK, unless for some reason their official speed limits and such aren't actually, you know, official.

As a practical matter, we use metric for many things in the US. The fact that we do not force everyone to change their customary units to metric really seems to irk some folks, but mostly outside the US.

[+] nwb99|3 years ago|reply
I believe the US legally defines the US customary units by metric counterparts anyway. https://www.nist.gov/pml/owm/si-units-length

Still, I'm probably the 1% of 1% of Americans who uses Celsius in daily life, except where I cannot (my car won't let me do hybrid miles and Celsius, ugh).

[+] wnevets|3 years ago|reply
Except the US uses the Metric system

> U.S. customary units have been defined in terms of metric units since the 19th century, and the SI has been the "preferred system of weights and measures for United States trade and commerce" since 1975 according to United States law.[1]

[1] https://en.wikipedia.org/wiki/Metrication_in_the_United_Stat...

[+] DiggyJohnson|3 years ago|reply
This seems offtopic and flame war bait, especially posted without additional commentary.
[+] kyawzazaw|3 years ago|reply
We use the Metric System quite frequently in Myanmar.
[+] _kst_|3 years ago|reply
So we have "ronna" or "R" for 10^27 and "quetta" or "Q" for 10^30.

I haven't seen the official binary equivalents.

For example, we have "yotta" or "Y" for 10^24, and "yobi" or "Yi" for 2^80.

Are we going have "robi" and "quebi"? I presume the abbreviations will be "Ri" and "Qi".

(I guess we don't need fractional binary prefixes. There's not much use for nanobytes.)

Of course since this was just announced today, I'm not really complaining.

[+] jl6|3 years ago|reply
So RB and QB for ronnabyte and quettabyte? What system could be described at that scale? Does Google store quettabytes of data?

Considering Seagate is shipping only 155EB (=0.000000000155QB) of storage per quarter[0], reaching the QB scale seems a way off.

[0] https://www.forbes.com/sites/tomcoughlin/2022/08/21/c2q-2022...

[+] count|3 years ago|reply
Data xfer'd vs. data stored.
[+] rnhmjoj|3 years ago|reply
Is anyone seriously using prefixes above Giga, besides for counting bytes or boasting numbers in popular science articles?

In physics, in practice you either state the number in exponential notation and don't care abut it or for brevity introduce a more appropriate unit: barns (10⁻²⁸ m²) and electronvolts (10⁻¹⁹ J) in nuclear physics or solar mass (~10³⁰ kg) in astrophysics, etc.

[+] robomartin|3 years ago|reply
> the Earth weighs approximately six ronnagrams

This is from a Physics forum? Really?

No! The Earth does not have weight! It has mass. Weight is a force. It is a function of gravitational pull between two masses.

If you want to talk about force you have to use Newtown's Law of Universal Gravitation:

  F = (G * m1 * m2) / r**2
You could speak in terms of gravitational pull between the earth and the moon or any other object in space, and that's about it.

I can't see how the concept of weight makes any sense when it comes to a planet. At all. Think of a hypothetical object in the middle of space with nothing whatsoever around it for millions of light years. No weight. Mass, of course.

You can't just use earth's 9.8 m/s*2 to convert from Kg to Newtons...that makes no sense at all in the frame of reference of any planet, even earth.

This isn't pedantic at all. Try to take a physic test anywhere and confuse these concepts, units of mass and force and see how well you do.

[+] adrian_b|3 years ago|reply
It is very important to distinguish the 2 physical quantities whose standard names are now "force" and "mass", but it is debatable whether it was good choice to arbitrarily assign to the word "weight" the meaning of a force and to establish the new word "mass" (new with this meaning) for what is now called "mass".

The word "weight" and its equivalents in other European languages, e.g. "poids", "pondo" etc., have been used for thousands of years principally to name the quantities measured by weighing with a balance, which are masses, not forces, and only seldom and mostly metaphorically and non-quantitatively to refer to a force. By etymology, such words derive in one way or another from the operation of using a weighing balance, e.g. "pound" means "hanging", from hanging objects on the weighing scales.

The word "mass" has been used for thousands of years only with a meaning that had nothing to do with a measurable quantity, but only to name some amorphous piece of some material, such as dough, clay, soil, rubble.

A wiser choice would have been to name as "weight" what is now named "mass" and to use a name such as "force of gravity" for what is now named "weight".

Such a terminology would have kept the continuity with the traditional meanings of the words and would not have offered opportunities for the majority of the people, who even today continue to use those traditional meanings in colloquial language, to be corrected by those who have made an arbitrary choice to assign new meanings to old words.

Unfortunately there exists a very large number of scientific or technical terms whose meaning has been changed some time during the last few centuries, sometimes intentionally, due to questionable decisions, but in many times due to various errors or misunderstandings.

Even when such names reflect very serious errors of those who have coined them, their meaning can no longer be changed, as too much new literature has accumulated, which uses the new meanings.

[+] hitpointdrew|3 years ago|reply
Can someone ELI5 how you “weigh” the earth? Isn’t weight based off gravity? And gravity is relative to the mass of the object you are on, for example we say you would weigh less on the moon and more on Jupiter. So how exactly to you weigh a planet, and why would that even be useful? Do you assume some theoretical force and hypothetically place the earth on a scale and apply that force? When talking about planets isn’t mass a better way to measure and classify rather than weight?
[+] Aardwolf|3 years ago|reply
> "Jupiter, that's about two quettagrams," he added—a two followed by 30 zeros.

But the sun is 2000 quettagrams... looks like we need another higher prefix

[+] wolfi1|3 years ago|reply
I'm disappointed that hella has not become a prefix
[+] ordu|3 years ago|reply
The strange thing is the symmetry. Why these prefixes cover multipliers from 10^-30 to 10^30? Why not 10^-20 to 10^40? Where the symmetry comes from?

Is it just people think that symmetry is a good thing, and for example they added 10^-30 despite the lack of demand? Or there is some deeper reason? Or it is more like one of those coincidences?