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Comment by cogman10 | Hacker News Reader

I see this happen all over the place. Instead of 1 Mg, you'll see thinks like 1000 kg.

I think power is the only metric unit I've seen where the common unit also often follows metric notations. 1 kW, MW, GW, TW.

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> Instead of 1 Mg, you'll see thinks like 1000 kg.

Yeah, I do this a ton myself. I apologize.

I object to your joke on the basis of accuracy. A tonne is 1000 kg, but a (long, short) ton is roughly 1016 kg or 907 kg respectively.

slow clap

> I think power is the only metric unit I've seen where the common unit also often follows metric notations. 1 kW, MW, GW, TW.

You might just not recognize them as such.

Ampere, Volt, Ohm, Tesla, Newton, Pascal, Hertz, Joule, ... are all SI units or directly derived from SI units and used with SI-prefixes regularily.

kg is the base SI unit, so 1000 kg is more natural than 1 Mg.

The fact that kg is the base unit does not make much sense except for historical reasons when the choice was made. A very bad choice if you ask me.

I blame the French... We could have had it all properly and use grave... But no, too big... One of the few ugly bits of SI system. In general otherwise it all just works together so nicely.

Then again it's not only weird unit we have, dB is the other one. Ofc, units are nicer to handle, but still... Not that bell isn't weird unit anyway.

I agree that bel is a weird unit. To be fair, it's not "in" SI, but just "accepted for use with". I'd also argue that candela and mole are weird for other reasons, and they're SI for real.

The mole is I think for historical reasons, to not piss off chemists too much.

I did not know that we were, again, to blame. But at least we have the one and only official and beautiful kilogramme and meter prototype in Sèvres, near Paris.

And, again the French way, it is not possible to see them!

They may call the kilogram the base unit, but in practice no one talks about millikilograms (just "grams") or microkilograms (just "milligrams"). The gram might be formally defined in terms of a 1 kg physical mass, but for the purpose of SI prefixes the gram is the real base unit and there is nothing wrong with saying 1 Mg instead of 1000 kg.

Also nobody says 1 kilokilogramme (1000 kg).

This isaid, the mass base unit in SI is really the kg, even if g would be natural (and indeed people will say 1 g instead of 1 millikilogram).

I was always annoyed by kg being the base unit (and I had to drag this suffering throughout my PhD in physics) but this thread opened my eyes on the possibility to use "compensating" prefixes on the kg (millikilogram to say gram) - it is a shame I did not think about that before to drive everyone crazy :)