How come people say 5,000 km and not 5 Mm?
why not just say millions of meters or Mega meters?
Familiarity I guess. Mega isn’t really a widely used prefix outside of computers. We even say tons instead of megagrams.
And yet we say megatons.
Instead of teragrams.
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.
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And 7.62 is just .30 caliber rebranded
and the old gauge system for shotguns.
I’ve only recently gotten my foid card and am learning to shoot and that shit confuses me so much.
But only in regards of nuclear bombs.
And your mom (⌐■-■)
megaton, megawatt, megapascal, megacandela (for military flares), megahertz, megajoule, megaohm, megabequerel
Megatron
That’s a lot of Trons
That’s bad comedy
Megan
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.
Apparently they were going to use gram for what we now call kg, but decided to make it kg. I expect it’s because we used grams so much for food.
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.
Odometer readings
“I’ve driven 112.326 megameters” takes the same amount of time to say as 112,326 kilometers. 🤷♂️
Megameters sounds scary and I don’t want to alarm the people I’m talking to.
Jokes on you elite dangerous uses Mm/s for lowest speeds in supercruise before it changes to “c” for relative to light speed
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
There’s also scientific notation which eliminates having to use these prefixes so you can more easily compare and manipulate numbers.
I do. Unfortunately, I don’t have many opportunities to do so. Which may be the reason why people don’t say megameter.
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.
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.
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…
Would it surprise you to know that there is a unit of length that is specifically the distance between the earth and the sun?
It’s called Astronomical Unit.
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.
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.
Can we do 5E6 like on the calculators? Is that common enough?
yeah but sadly not enough people know how to read that. sadface.
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.
We routinely count vehicle odometers in thousands of kilometers, AKA Megameters. I’d say it’s a common enough measurement to popularize Megameters
That really doesn’t come up often enough.
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)
Here i learn mega, giga, tera. But show up in computer which is like place you most commonly see them.
Yeah but the real question is how many is a Brazilian?
1228
nobody will stop you, i’ve seen some publications use gigagrams instead of thousands of tons
weirdly enough SI unit for mass is kg not grams
My physics teacher once told us that this was due to the influence of disciplines that calculate with huge masses, say in astrophysics the weight of a planet or the the amount of oxygen within it. Don’t know how much of it is true but the basic tenet of everyone preferring the numbers that they work with on a daily basis having as few prefixes as possible as it makes mentally handling and remembering them easier.
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.
SI also does meter instead of cm, so it overall checks out.
Having meter as a base unit makes more sense than kg because meter lacks any prefix.
Megamind?!
I’ve seen megameters used in the context of astronomical distances, but not terrestrial ones. I think terrestrially, the familiarity of kilometers helps with a sense of scale.
The beauty of the metric system is you don’t lose a sense of scale from using a higher unit because you can intuitively know 1Mm is 1000km.
