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How come people say 5,000 km and not 5 Mm?
why not just say millions of meters or Mega meters?

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[-] bjoern_tantau@swg-empire.de 78 points 7 months ago

Familiarity I guess. Mega isn't really a widely used prefix outside of computers. We even say tons instead of megagrams.

[-] person@lemm.ee 62 points 7 months ago
[-] bjoern_tantau@swg-empire.de 35 points 7 months ago

But only in regards of nuclear bombs. Maybe it's because of the scientific origins of these fields. Probably the same reasons why Americans measure firearm munition in mm.

[-] David_Eight@lemmy.world 6 points 7 months ago

But only in regards of nuclear bombs.

And your mom (⁠⌐⁠■⁠-⁠■⁠)

[-] joel_feila@lemmy.world 2 points 7 months ago

we do list volcanic eruptions in megatons of TNT. The makers of the first a bomb pick it since the largest explosion ever made by then was a ship full explosives and some had calculated how many tons of TNT that ship was carrying

[-] anguo@lemmy.ca 14 points 7 months ago

Instead of teragrams.

[-] skillissuer@discuss.tchncs.de 31 points 7 months ago

megaton, megawatt, megapascal, megacandela (for military flares), megahertz, megajoule, megaohm, megabequerel

[-] Turun@feddit.de 5 points 7 months ago

To be fair, mass is weird because the base unit is kg (yes, the name includes a prefactor). I have no idea how they managed to fuck it up that badly.

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[-] gedaliyah@lemmy.world 2 points 7 months ago

Yes, I think it's a question of use. I can't think of many examples where you would quickly need to know the measurement to the nearest Mm. Maybe if for some reason you deal with a lot of lunar orbits? Diameters of exoplanets?

Any earth distances we need to know with greater precision, and any stellar distances are probably better measured in light years, etc.

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[-] Kolanaki@yiffit.net 17 points 7 months ago

Megameters sounds scary and I don't want to alarm the people I'm talking to.

[-] kinttach@lemm.ee 16 points 7 months ago

On Earth it’s just not needed. In nearby space it could make sense — distance to the Moon is 369 Mm. Distance to the Sun 149 Gm. But people aren’t good at visualizing the difference between kilo-, mega-, and giga-. It isn’t obvious from those numbers just how much further away the Sun is.

[-] leftzero@lemmynsfw.com 3 points 7 months ago* (last edited 7 months ago)

For interplanetary space and beyond the time it takes for light to cross the distance makes more sense, I'd say. The moon is about half a second away, the sun about eight minutes, Voyager I a bit less than twenty hours, Alpha Centauri or Barnard's about four years, and so on...

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[-] Kissaki@feddit.de 16 points 7 months ago* (last edited 7 months ago)

I do. Unfortunately, I don't have many opportunities to do so. Which may be the reason why people don't say megameter.

[-] Rhaedas@fedia.io 14 points 7 months ago

That unit is used a lot in the space game Elite Dangerous. Never saw it used before that, but it made sense because it's the next jump up in large units, and it also helps keep the UI clean looking.

[-] mlg@lemmy.world 9 points 7 months ago

Jokes on you elite dangerous uses Mm/s for lowest speeds in supercruise before it changes to "c" for relative to light speed

[-] ech@lemm.ee 9 points 7 months ago

I wish we would. It sounds awesome to say.

[-] Kissaki@feddit.de 4 points 7 months ago

Be the change you want to see!

Hopefully, you have many opportunities to use it.

[-] LostXOR@fedia.io 9 points 7 months ago

As a KSP player I use megameters all the time lol.

[-] z00s@lemmy.world 2 points 7 months ago

Ah yes, Krazy Soup Plantation

[-] IsoSpandy@lemm.ee 9 points 7 months ago

Well mainly because where we might need to use these units, we have more standard non si units, we use AU, Light years and Parsecs where Megameters, Gm, TM etc would be useful

[-] ShepherdPie@midwest.social 5 points 7 months ago

There's also scientific notation which eliminates having to use these prefixes so you can more easily compare and manipulate numbers.

[-] skillissuer@discuss.tchncs.de 9 points 7 months ago* (last edited 7 months ago)

nobody will stop you, i've seen some publications use gigagrams instead of thousands of tons

[-] takeheart@lemmy.world 13 points 7 months ago

weirdly enough SI unit for mass is kg not grams

[-] LostXOR@fedia.io 3 points 7 months ago

I've always found that strange. I guess a kilogram is a lot closer to "human scale" than a gram, maybe that's why they picked it.

[-] joel_feila@lemmy.world 2 points 7 months ago

yeah humans do really need a small, inch and cm, a medium, meter and feet, and a big, mile and km.

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[-] umbraroze@lemmy.world 6 points 7 months ago

Aside of kilometers there used to be "myriameter" (a myriad meters = 10,000 m = 10 km).

Fun thing, in Sweden they use mil for 10 km. In Finland there's peninkulma for 10 km, but it's very archaic.

[-] 0485919158191@lemmy.world 5 points 7 months ago

We already have this in Sweden. 10km in Sweden is 1 mil (Swedish mile).

When we sell/buy used cars and other types of vehicles we always count the mileage in Swedish miles.

Kilometers work but is just absurd when you start talking about 100k+ kms.

[-] SteveDinn@lemmy.ca 5 points 7 months ago* (last edited 7 months ago)

Scientific notation for everything: 5 x 10^6 m. Seriously though, I think it would be easier to think about it in megameters or gigameters if it were more standard to do so.

[-] someguy3@lemmy.ca 2 points 7 months ago

Can we do 5E6 like on the calculators? Is that common enough?

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[-] captain_aggravated@sh.itjust.works 4 points 7 months ago

Main reason is nearly no one needs to measure things in megameters. Megameters would be a unit to measure the diameter of planets in, maybe the orbital altitudes of some moons. Our moon for example is ~384Mm away. Distances between planets, distances between stars, and distance between galaxies are many, many orders of magnitude farther than that.

As most of us rarely travel more than 1,000 kilometers very often, it's the biggest unit most people are familiar with on an intuitive level.

I'm still convinced people don't actually use the metric system's power of ten design. Like no one uses centigrams or kiloliters either. They've picked out units that are pretty close to the ones in the Imperial/Customary system, kilograms are used instead of pounds, grams are used instead of ounces, kilometers are used instead of miles, meters are used instead of yards, centimeters are used instead of inches, millimeters are used instead of sixteenths of an inch and so on. Want to confuse a European? Draw up some blueprints in hectometers.

[-] Gabu@lemmy.world 3 points 7 months ago

Your assumption that an imperial system is some kind of default tells us more about your limited worldview than about measurement units.

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[-] stoy@lemmy.zip 4 points 7 months ago

Here in Sweden and Norway we have the Scandinavian mile, "mil", it is 10km.

[-] KyuubiNoKitsune@lemmy.blahaj.zone 3 points 7 months ago

We also use deciliter and centiliters, which is odd for some.

[-] SmoothLiquidation@lemmy.world 3 points 7 months ago* (last edited 7 months ago)

It is 2.445 kilomiles from Los Angeles to New York.

[-] joel_feila@lemmy.world 2 points 7 months ago

that's a whole 12 Mft

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[-] someguy3@lemmy.ca 3 points 7 months ago

Not much need to use Mm, it doesn't come up very often. So when it does it's easier to use thousands of km so as to not confuse people with "another" measurement.

[-] ebc@lemmy.ca 2 points 7 months ago

We routinely count vehicle odometers in thousands of kilometers, AKA Megameters. I'd say it's a common enough measurement to popularize Megameters

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[-] Drummyralf@lemmy.world 3 points 7 months ago* (last edited 7 months ago)

In our primary schools, we learn our children mili, deci, centi, deca, hecto and kilo, and how to calculate between them.

Beyond that or below that is used either in science classes or specific usecases and not known by the whole population at large.

Since people use what they know, they'd never use mega as a common way of measuring. We mostly use km for distance, and only in specific cases we might use, say, hectometers or decameters.

5 megameter is not wrong, but I don't call 34 cm 3,4 decimeters either(unless decimeters make sense of course :p)

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[-] alphapuggle@programming.dev 2 points 7 months ago

Yeah but the real question is how many is a Brazilian?

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this post was submitted on 08 Mar 2024
167 points (96.1% liked)

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