[chr]

   Then, the ejected debris that created the canyons likely soared over the lunar surface and then collided with it at speeds of about 2,237 miles per hour (3,600 kilometers per hour).

Oddly adding a veil of precision to an estimate of a kilometre per second.

[hansvm]

That's only a problem if your favorite method of representing uncertainty is in-band signalling via a technique like significant figures.

[justonceokay]

You could translate the units and then also translate separately the error bands (assuming +/- 100 km). But “2237 mi/hr +- 62 mph” sounds pretty silly.

[dmurray]

That's nothing! They determined that one valley formed 3.8 billion years ago, and the other one, 3.8 billion years plus or minus 10 minutes.

[hulitu]

> That's nothing! They determined that one valley formed 3.8 billion years ago, and the other one, 3.8 billion years plus or minus 10 minutes.

Now that's what i call precision. How did they measured it ? With a pendulum ? /s

[robin_reala]

US people typically want numbers translated into American football fields it seems. So around 39,000 football fields an hour might be more obvious.

[dandelany]

Please be complete if you’re gonna translate to American units. That’s 117,000 football fields per football game, or 325 per commercial.

[smallmancontrov]

Does the hour include or exclude ad breaks?

[rzzzt]

10 m/s = 36 km/h, I believe they started from a round number.

[bena]

Yeah, they just did the conversion and slapped it on there. Should have said "about 2200 mph".

[JoshTriplett]

It's unfortunate that the only written mechanism we have for expressing a lack of precision is scientific notation, which tends to be obfuscating for numbers at this scale: if you write "3.6e3 kph (2.2e3 mph)", you make it clear approximately how much precision you do and don't have, but it's less obvious-at-a-glance for the target audience of an article like this.

[carlmr]

Or use kps and not lose additional precision every time you translate units?

[kingds]

2200 would improperly add an extra significant figure, "about 2000" would be okay.

[beAbU]

Its because they started with "roughly 1km/s", which was deemed too difficult to understand for pleb readers, so it was converted to km/h, which is more relatable. Then it was converted to mph for the US audience, and the author just did a straight conversion without really considering the madness that is " about 2237 mph". I hate it when they do this.

1-2km/s, which is a reasonably accurate estimate for these things, should have been translated to "2000-4000mph" and it would have been perfectly good enough.