> "The impact ejected at least one million kilograms of rock from Dimorphos’s 4.3-billion-kilogram mass. The debris formed a tail that stretched for tens of thousands of kilometres behind the asteroid."

"one million kilograms" = one gigagram

"4.3-billion-kilogram" = 4.3 teragram

"tens of thousands of kilometres" = tens of megametres.

I don't understand the media's reluctance to use large SI prefixes for mass and distance, when they'll happily use them for electrical units.

I have never heard of the use of kilo/mega/giga used for standard mass or distance units, either in the media, scientific literature or anywhere else (except kilometer, and kilogram, but kg IS actually the standard unit, not g)

Only place where I've witnessed it's use is during my own personal musings while sitting on the loo. Same goes for money. "Gigadollars" has a nice ring to it but it's not used :(

There are other units of measurement when the numbers get really big, like AU, lightsecond/minute/year, Solar Mass, etc. I'm no scientist, but I also think when you get to the astonomical scale, order-of-magnitude relative measurements is more useful knowing a galaxy's mass to the nearest gram.

No, they don't get used, but they should be. We all understand metric prefixes now, and use them for other units. I'm saying we should stop using "thousands/millions/billions of" kilometres/kilograms, and start using mega/giga/tera metres/grams.

Meh, I honestly dont think you lose or gain anything going either way. Spoken language is messy AF and I honestly don't see it helping.

Case in point, people might think you are conflating nuclear bombs and mass if you say "this ship weighs 5 megatons".

Also depending on who you ask, gigagram either sounds like way more, or way less, than 1000 tons.

And for scientific writing, 1e9g is about as clear and explicit as it gets.

However they are frequently used for tons (the megagram variety, not sure about imperial). Kilotons are of course famous because we measure explosions and other forces in kiloton-tnt-equivalents, but Megatons and Gigatons are also used (the later commonly for emitted CO2)

It's also a peculiarity of kilograms. The kilogram rather than the gram is the SI base unit for mass.

Thus it's normal to use e.g. 1e6 kg rather than 1e9 g.

But metre is an SI base unit and people say "thousands of kilometres" instead of megametres.

I think they're just not well understood by most people. 1000Kg is a small car. 1Mg is...who the fuck knows. You can tell someone a building weighs 1Gg but they're gonna stare at you funny until you tell them it's about 1000 small cars.

OTOH, 1KHz has no basis in physical reality for normal people but they know 1KHz is 1000x faster than 1MHz so it works nicely for things like "is my new computer faster than my old computer" (at least a decade ago, I don't see clocks advertised much at all anymore).

Well of course if it doesn't get used then most people will not be familiar with it — that's the point. We should encourage the use so people become familiar with them, so we can stop using "thousands of" and "millions of".

Re kHz, I think most people understand frequencies we can hear. (1 kHz is close to a high C note). MHz and GHz are radio frequencies.

1 megagram is a ton, which is widely used. A lot of stuff is measured in tons, including cars (“this car weighs almost two tons, which is pretty heavy for a sports car”), cargo (20-ton train car), etc.

It stops on the ton, though - “40 thousand tons of grain” - gigagram isn’t used.

Isn't 1 megagram a tonne? A ton is a slightly larger non-SI unit.

1KHz is faster than 1MHz? Our computers are getting slower and slower?

...GHz ?

They really should make the gram the official unit now that they moved away from the "block of platinum in a basement" model

that's why the correct unit here would be megakilograms :)

Media want attention which is correlated with the number of zeroes in the header.

> Missed opportunity to use the term megagram.

Did you mean gigagram?

Two comments saying this. Doesn't mega mean 10^6 aka 1 million?

yes, but "kilo" is 10^3 already so 10^6 * 10^3 = 10^9 -> giga

Wow, duh. That "kilo" slipped right past me as I thought about that.

Reminds me of this kurfuffle!

https://youtu.be/6egeUxIEQnM

Human brains sure do funny things sometimes.

Wouldn't that be a gigagram? Even more cool.

how ever you measure it, the street value of all that powder has got to be astronomical

I think that would insinuate more precision than their methodology for measurement could provide.

Also missed the opportunity to say "10M hectograms" or "100M decagrams".

Or 1000 tonnes