2023-08-03

An article about upgrades to the Cygnus cargo vehicle uses only metric units in space.com.

The comments include a discussion about the metric ton (or tonne) and the use of the metric system.

You have to scroll quite far to reach the discussion so I have copied it below.

A lot of the formatting was lost in copying the comments, including the indentation that shows who was replying to whom, so I have put the author of a comment in bold type and the person he is addressing in italics, with the date they made their comment. For example:

JohannAugustEberhardt

mandrewa 23 days ago:

The article was published more than three weeks ago, but only showed up in my search today.

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Comments to Northrop Grumman planning Cygnus upgrades2023-08-03

JohannAugustEberhardt

mandrewa 23 days ago: I presume that by mt, you mean metric tonne? Because stricly speaking, t is the symbol for metric tonne, so mt would be millitonne, which equals kilogram.

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mandrewa

JohannAugustEberhardt 23: days ago Yes, mt stands for metric ton.

JohannAugustEberhardt

mandrewa 23 days ago: Why not just use t? British and American tons are tn iirc. If you use mt for tonnes, how do abbreviate megatonnes? Mmt? mMt?

pathfinder_01

JohannAugustEberhardt 23 days ago: Because t is also for Tons(2,000 pounds). Megatons can refer to the yield on Nuclear weapons. Yeah confusion all around.mandrewa JohannAugustEberhardt 23 days ago Well, most people in America, when the say 'ton,' they mean 2,000 lbs. But you'll notice that 2,000 lbs is kind of close to 1,000 kilograms. And that's where the idea of the metric ton comes from. So a metric ton means 1,000 kilograms. And that vocabulary has been around for some time -- at least 50 years.And outside of the United States, the metric ton, or 1,000 kilograms is also a common unit of measure, although it may have a different name depending on the country.1,000 kg, metric ton, and tonne are all the same thing. But the obvious problem with tonne is that it sounds the same as ton, which means something different, and thus tonne will inevitably create confusion.And since I wish to decrease confusion and not increase it, I speak in terms of metric tons.

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JohannAugustEberhardt

mandrewa 23 days: ago I get that. Still, since the 2000lbs ton is abbreviated tn or tn.sh. and the metric tonne t, adding mt to the mix looks like adding confusion to this. Also, don't Americans generally use the metric system in school and university?

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Michael Weidler

JohannAugustEberhardt 23 days ago: If you don't know, why are you sticking your nose into business which does not concern you? While metric is taught in several grades in US schools, we really don't use it for much outside of science.

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JohannAugustEberhardt

Michael Weidler 22 days ago: So you are saying "If you don't know something, you are not allowed to ask." This is a horrible message and rude as well.You also say that my assumption about metric being used in school and science was exactly right, so according to you I actually did know. Which makes this even weirder. Please keep in mind that standardisation concerns all of us. t is internationally recognised as the symbol for the metric tonne, in the US as much as everywhere else. NASA for example also uses it that way. Standardisation doesn't have to be about everybody using the same units, but it should at least provide an unambiguous way of communicating units. Often enough, lifes depend on this and dismissing that topic like you is pretty reckless.

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▪ Michael Weidler

JohannAugustEberhardt 14 days ago: Metric is not used in schools. It is taught off and on in various grades - but it is not "used". Our football fields are not delineated in meters. Outside of STEM courses, metric is not utilized for anything in schools. The only people in the US who know what a kilo is are drug dealers. Nobody knows or cares how long a kilometer is.

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gunsandrockets

JohannAugustEberhardt 23 days ago: editedU.S. aerospace/aviation practices are a missmash of metric and English units. Civil aviation aircraft altitudes are measured in feet rather than meters.Even the engineering of Project Apollo did not use metric measurements.The average American does not use nor is familiar with the metric system. STEM educated Americans, of course are different.

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mandrewa

JohannAugustEberhardt 23 days: ago t is an abbreviation for ton (2,000 lbs) in the United States.

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JohannAugustEberhardt

mandrewa 23 days ago: According to Wikipedia, this is not true:The BIPM symbol for the tonne is t, adopted at the same time as the unit in 1879. Its use is also official for the metric ton in the United States, having been adopted by the United States National Institute of Standards and Technology (NIST).

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mandrewa

JohannAugustEberhardt 23 days: ago That's not what most people have been taught in the United States. I think the majority of the population still thinks in terms of a ton being 2,000 lbs. It's probably the massive majority. I don't know what the schools are doing now. I know what I was taught.

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Roy Trubshaw

mandrewa 22 days ago: Imperial ton = 2240lbs = long tonMetric tonne = 1000kg approx = 2200lbUS ton = 2000lbs = short tonWhen in doubt ask your local longshoreman!Also: trust you USAians to muck up perfectly good imperial units! (Don't get me started on ridiculous 16fl oz pints!)Though kudos for being the last bastion of the British Thermal Unit. :)