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Earth Science

Earth Now Weighs Six Ronnagrams: New Metric Prefixes Voted In (phys.org) 81

An anonymous reader quotes a report from Phys.Org: Say hello to ronnagrams and quettameters: International scientists gathered in France voted on Friday for new metric prefixes to express the world's largest and smallest measurements, prompted by an ever-growing amount of data. It marks the first time in more than three decades that new prefixes have been added to the International System of Units (SI), the agreed global standard for the metric system. Joining the ranks of well-known prefixes like kilo and milli are ronna and quetta for the largest numbers -- and ronto and quecto for the smallest.

The change was voted on by scientists and government representatives from across the world attending the 27th General Conference on Weights and Measures, which governs the SI and meets roughly every four years at Versailles Palace, west of Paris. The prefixes make it easier to express large amounts -- for example, always referring to a kilometer as 1,000 meters or a millimeter as one thousandth of a meter would quickly become cumbersome. Since the SI was established in 1960, scientific need has led to a growing number of prefixes. The last time was in 1991, when chemists wanting to express vast molecular quantities spurred the addition of zetta and yotta.

The new prefixes can simplify how we talk about some pretty big objects. "If we think about mass, instead of distance, the Earth weighs approximately six ronnagrams," which is a six followed by 27 zeroes, [sad Richard Brown, the head of metrology at the UK's National Physical Laboratory]. "Jupiter, that's about two quettagrams," he added -- a two followed by 30 zeros. Brown said he had the idea for the update when he saw media reports using unsanctioned prefixes for data storage such as brontobytes and hellabytes. Google in particular has been using hella for bytes since 2010. "Those were terms that were unofficially in circulation, so it was clear that the SI had to do something," he said.

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Earth Now Weighs Six Ronnagrams: New Metric Prefixes Voted In

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  • I'm sorry to hear that Richard Brown is sad. Is it because the weight of the earth or something else? He has a friend to call in me if he ever needs one.

  • by Anonymous Coward
    Six ronnagrams is completely meaningless to me. I'd rather have it expressed in kilograms.
    • I agree. They need to be common enough that you become familiar with them or there needs to be some pattern to them.
      the letters currently are d,c,m, micro which is a backwards u, n, p, f, a, z, y, r, q
      We would have be much better off using the alphabet and starting with a.
      Even starting now, we would be much better off either adding it as either q,r,s,t,u,v,w,x,y,z
      or sticking with the z,y doing z,y,x,w,v,u,t,s,r,q

      • Do we really need more units? Why not just use the units we already have? The earth is 1/333,000 Solar Masses (SM).
        • In many ways, your example shows why the metric system needed to define something. The advantage of metric is that it is a single standard rather than a bunch of different standards stitched together. People (and even scientists) like to work with relatively small numbers. The concept of solar mass, AU, light-year, parsec, ... all were invented in order to avoid working with very large numbers. But all of these examples are very much like imperial units. They take some object (the sun) and make it into the

          • Re:That's stupid. (Score:4, Insightful)

            by Opportunist ( 166417 ) on Saturday November 19, 2022 @07:09AM (#63063407)

            Humans think in terms of relatives. Saying something has a mass of X or is Y away means little if you have nothing to compare it to. We use meters and kilometers (or feet and miles for you imperial types) in everyday life and have a "feel" for them. 5 meters is what a room is across. 10 meters is a pretty big room. 100 meters what you need to play football. A mile is something you can walk comfortably without thinking. 10 kilometers is a really quick drive with the car. 100 kilometers is ... you get the idea.

            Nobody has any kind of "feel" for distances beyond 10,000 kilometers. Earth is 40,000 kilometers around. Aside of "that's really a lot", there isn't really anything you could sensibly compare it to.

            Big numbers also don't really add to the simplicity. A lightyear is 9.5 trillion kilometers. There's nothing we could immediately compare that. That's like ... erh ... about a trillion quick car rides. So if you made one car ride a day, you'd ... can you imagine that? I can't. Most people won't be able to.

            Yes, you can calculate it, but it fails to be representative. But it is a new unit to deal with that is more handy when comparing stuff. The closest star is about 4 LY away. Yes, that's a really, really, REALLY big distance (Voyager, which is the thing that we sent as far out as we can by now, is about 1 lightDAY away now, in other words, Proxima Centauri is like 1500 times further away than Voyager... no, that's beyond imagination either), but it's something we can build another comparison on. Because if we know this is "four", then something that is "ten" is more than twice that.

            Humans tend to think in comparisons. We compare things to other things we know. That's how we assess things. If you cannot put something into perspective, it can as well not be quanitified.

        • This.

          Maybe with scales that are beyond sensible for our "normal" units, we should try to implement something more tangible. And before some idiot comes along with football stadiums and libraries of congress, yes, there are sensible ways to deal with this. That's why we use lightyears for distances between stars instead of billions of miles.

          Measuring planet masses in multiples of some other relevant mass is sensible.

      • Micro is denoted by the Greek letter mu.

      • micro which is a backwards u

        No, it's the Greek letter mu.

    • by Roger W Moore ( 538166 ) on Saturday November 19, 2022 @02:16AM (#63063045) Journal

      Six ronnagrams is completely meaningless to me.

      Ronnagrams are meaningless to everyone when discussing the _weight_ of the Earth. Grams are units of mass, not weight.

    • lronnograms and thetameters? Are they sure the SI that named these wasn't Scientology International?
      • At any rate, we shouldn't allow George Lucas to keep naming our units. It's bad enough what he did with his characters.

    • What any internet rando thinks about the adoption of the prefix is irrelevant. What matters is whether the people that will actually use those units think, and whether they adopt it in standard discourse. Time will tell, but I suspect the same adoption had to happen for other recent prefixes, like zepto, yotta, etc.

    • Six ronnagrams is completely meaningless to me. I'd rather have it expressed in kilograms.

      A unit like this becomes useful when it enters everyday life. Remember when there was never a reason for tera-anything? Now we routinely use the prefix for hard disks and the federal budget.

    • In writing I much prefer scientific notation. I can appreciate when something is used in common (or formal) speaking it is much harder to do.

      What pisses me off is when people mix units, like 6 million terragrams, although it is more common to see things like 6 million MWh for me. I don't have enough fingers to back it out and put in a proper unit.

    • Or African Elephants.
    • Isn't a ronnagram an XRay of your "ronna"?
  • by jralls ( 537436 ) on Friday November 18, 2022 @10:55PM (#63062821) Homepage
    Too bad they didn't adopt bronto- and hella-. Absurdly large numbers deserve colorful and memorable names.
  • by RightwingNutjob ( 1302813 ) on Friday November 18, 2022 @11:00PM (#63062827)

    Do I learn a bunch of made up word prefixes and hope my interlocutors do the same, or do I use the 10 hindu arabic numerals we all know and say 6e27 in stead of "six whatevergrams"...

    • In writing, what you say it makes total sense.
      When expressed verbally, "six ronnagrams" has four syllables, whereas "six e twentyseven grams" (which might raise some eyebrows when spoken) has... well, seven.
      If you want to eliminate confusion and would rather say "six multiplied by ten to the power of twentyseven grams", well, that would take a long time.
      It gets even more complicated for small numbers, because you have to add a "minus" which adds two more syllables.

    • Do I learn a bunch of made up word prefixes and hope my interlocutors do the same, or do I use the 10 hindu arabic numerals we all know and say 6e27 in stead of "six whatevergrams"...

      So how much do you weigh? 52 thousand grams?

      If you're a layman (or talking to laymen) then you might describe the earth as weighing 5.972 × 10^24 kg. But if you're an astronomer talking to other astronomers you might really prefer to say about 6 ronnagrams. Especially if you're contrasting it to another planet like Mars that's only about 0.6 ronnagrams, or Jupiter that's ~2000 ronnagrams.

      There's a big benefit to changing units to numbers that people can somewhat visualize.

      • If you're an astronomer, you deal in quantities that are astronomically larger than units defined mostly by terrestrial applications. So you make up units to simplify things.

        The Astronomical Unit is the mean distance from the earth to the sun, about 1.48e9 meters. Useful for solar system dynamics calculations to keep all numbers within about an order of magnitude of unity. Velocities are usually given in AU per day instead of km or AU/sec.

        For stuff outside the solar system, the parsec and kiloparsec are fav

        • If you're an astronomer, you deal in quantities that are astronomically larger than units defined mostly by terrestrial applications. So you make up units to simplify things.

          The Astronomical Unit is the mean distance from the earth to the sun, about 1.48e9 meters. Useful for solar system dynamics calculations to keep all numbers within about an order of magnitude of unity. Velocities are usually given in AU per day instead of km or AU/sec.

          For stuff outside the solar system, the parsec and kiloparsec are favored units, on the order of 4 light years and 4000 light years respectively.

          My absolute favorite astornomical unit is the "dex" short for decimal exponent (kinda like the dB) and refers to ratios of "metals" in stars and galaxies derived from spectroscopy. The measurement is imprecise and the quantity has an enormous dynamic range. Totally unsuitable to real units.

          So what's the issue with formalizing a few of those more widely used made-up prefixes? If people need to talk about numbers in that volume now there's a more common language.

          • The issue is that there is no need to do this. Astronomers will still use their own units, and the layman will derive no benefit from additional prefixes meant to encompass astronomical quantities which won't even be used by astronomers.

            I suppose there are theoretical practical downsides with having to spend time adopting these prefixes, and the occasional software glitch where a parser or printer won't understand or output the new prefixes.

            But mostly it's pointless. And the real harm comes when people who

            • The issue is that there is no need to do this. Astronomers will still use their own units, and the layman will derive no benefit from additional prefixes meant to encompass astronomical quantities which won't even be used by astronomers.

              I suppose there are theoretical practical downsides with having to spend time adopting these prefixes, and the occasional software glitch where a parser or printer won't understand or output the new prefixes.

              But mostly it's pointless. And the real harm comes when people who should be analytical and serious devote their time quite publicly to trivial and pointless matters.

              Well I don't have any real intuition for 10^24 kg, and I certainly wouldn't remember 10^23 vs 24.

              But the fact that Earth is 6 ronnagrams and Mars is only 0.6, that's the first time I realized that Mars is only ~1/10th the mass of Earth.

              I think that is the actual benefit to the general public. Just like AU is a measure of distance the public kind of understands, the Earth being 6 ronnagrams is something people can remember, and when they hear about some extrasolar planet being X ronnagrams they're now better

    • Do I learn a bunch of made up word prefixes ...

      Thor: All words are made up.

    • You may not but in science some of the lesser known prefices get used more commonly. So just like you would (presumably) say 5 kg or 2 mm rather than 5,000 g or 0.002 m I'd typically say 5 PeV or 10 pb when discussing a neutrino energy or a cross-section with colleagues.

      Basically, it is planning for the future and will only be useful when comparing quantities with similar amounts much like hard drives moved from MB to GB and now TB and large storage servers are already measured in PB.
    • by AmiMoJo ( 196126 )

      These prefixes are useful when discussing things like the relative mass of planets. Using exponentials you conventionally keep the number between 1 and 9.999 recurring, so when comparing things you have to take care to watch for the exponent changing.

      6e27 4e28
      6Rg 40Rg

      That's why, for example, in electronics people usually use prefixes like k, m, u, n and p instead of just writing "1e-10f" on the schematic. It's less error prone and easier to parse.

      • by AmiMoJo ( 196126 )
        Gah, caught by Slashdot's attempt to parse HTML tags again. Should read

        6e27 < 4e28
        6Rg < 40Rg
  • 1000 Kilograms should be a Megagram

    Anyway, 10 to the 30th is not big enough when you are into astronomy - what is the mass of the Andromeda galaxy...

    • You said that wouldn't be on the quiz!!!

    • Yep - but it's also one of those convenient places like the hand (4"=10cm) where historical units line up just about perfectly with a nice power of ten metric value, making it really hard to convince people to change terminology.

      If the hand hadn't already faded as a commonly used unit when metric was taking over, I suspect it would have become at least as popular. Especially sitting right at the sweet-spot for volume like it does: one cubic hand = 1L.

    • The tonne isnâ(TM)t an SI unit.

    • You always could use Megagram if you wanted so (we are already using milligrams and micrograms in chemistry), but the root unit of mass in the international system of units continues to be the kilogram.

      According to legislation in force https://www.bipm.org/en/public... [bipm.org] The tonne is a "Non-SI unit accepted for use with the SI Units". "The tonne and its symbol t, were adopted by the CIPM in 1879 (PV, 1879, 41). This unit is sometimes referred to as 'metric ton' in some English-speaking countries."

  • I don't know who Ronna is but she should probably cut back on the bonbons and ice cream.

  • Ronna? Quetta? Tell me again how the metric system is easier to understand than the imperial system.
    • Lol, what are the imperial prefixes for 10^27 and 10^30?
      • Lol, what are the imperial prefixes for 10^27 and 10^30?

        Shit- and fuck- respectively. As in 10^27 grains is a shitton and 10^30 grains is a fuckton. Only applies to imperial long fucktons of course, not short.

      • by ghoul ( 157158 )
        Charles and Lilibet
    • You can use prefixes like Ronna and Quetta with imperial units where relevant, just like milliinch (mil), microinch, kilopound (kip). It's not often that you will need 10^27 so these particular ones could likely remain a curiosity except for a specialists in a niche. In computer science we already need to talk about Exabyte and Zettabyte (10^18 and 10^21 bytes) ( https://en.wikipedia.org/wiki/... [wikipedia.org] "The Zettabyte Era or Zettabyte Zone[1] is a period of human and computer science history that started in the mi

  • 6e27 g - isn't that just ten thousand mole of grams?

  • If the earth was covered in a monolayer of coronavirus, there would be about 42 ronna of 'rona...

    https://twitter.com/Vic_Colema... [twitter.com]

  • Omg you idiots! A ronto is huge!

  • Those damn elitist leftist academics with their new fangled pronouns. /s

  • The use of 'bronto' for 10E27 is new to me. I'd previously encountered it as 10E15, in a list of SI prefixes that included bronto and exa as 'provisional'.

  • Is a ronnagram or a quectometer bigger or smaller than a LoC? What's the conversion ratio?

  • ... for one's new-born overweight baby-girl ;-)
  • Just use the power of 10. Why make up new words?

  • Now we just need units/prefixes for four candles.
  • I know SI users like to use prefix-grams as a unit for weight, but the SI unit "gram" is a unit of mass, NOT weight. SI has a perfectly fine unit of weight, the newton.

    When will the SI fanatics learn to use SI as designed? Which would mean that weight is measured in newtons plus prefix - kilonewtons for someone's weight, for example.

    Note, by the by, that the "pound" is either a unit of currency (as in "I have 28 pounds, is that going to be enough for lunch at your restaurant of choice?"), or of weight (

  • Hep me Ronna, hep hep me Ronna

    Glad they fin'ly get 'ronna it

  • Ronnagrams - the perfect unit to finally weigh yo momma.. Been calling it YoMommagrams all this time..

    Yo momma is fat.

  • I would recommend https://www.npl.co.uk/si-prefi... [npl.co.uk] that is more complete
  • a 2 Ronnabyte SSD!

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