4 ms·

I’ve been using Mm too, but only when I have a reasonable expectation that it will be understood. IOW, rarely. But also, I still have the Earth–Moon distance i

by hanche 5y ago

I’ve been using Mm too, but only when I have a reasonable expectation that it will be understood. IOW, rarely. But also, I still have the Earth–Moon distance internalized as 385000 km, not 385 Mm, since that is what I learned as a kid. But stating the Sun–Earth distance as 1 AU is just a tautology, restating the definition, and hence void of information. I suspect you’re jesting. ;-)

sellyme 5y ago
> I’ve been using Mm too, but only when I have a reasonable expectation that it will be understood. IOW, rarely. Yeah, I mainly only use it in chats (where I can immediately explain it if needed) or in person (where the actual pronunciation of "megametres" makes it pretty obvious). "Mm" and "Gm" being somewhat difficult to google due to "mm" and "gm" being different SI units makes it untenable to just expect people to work it out on their own. > But stating the Sun–Earth distance as 1 AU is just a tautology, restating the definition, and hence void of information. I suspect you’re jesting. ;-) To be clear, I don't mean that you'd answer "1 AU" if someone asked you how far away the sun was - obviously that's completely worthless information! The discussion was just on what units and prefixes are used for various magnitudes of measurement, and the AU is a fantastic unit to use for things that would otherwise be measured in hundreds of gigametres. For example, if you had a table containing the distances between various celestial bodies, it would be very convenient to have "Sun <-> Earth: 1 AU" in there along with things like "Sun <-> Mars: 1.5 AU".