On: Finding the longest straight line you could sail without hitting land

[wlll]

It's a sphere in human scale.

[kgwgk → wlll]

What do you mean by “human scale”? It may be a sphere in much larger scales (~1000km) but I’d say it’s far from being a sphere in human scale (~1m).

[wlll → kgwgk]

It's based on context. So something like a scale that makes sense when going about your average human business. For instance, the sun is 150 million miles from the sun. It's not, it's slightly less, but for "normal" human activity (eating, sleeping, sailing in straight lines, programming web apps, etc. etc.) it doesn't matter, it's close enough.

So for the earth (as someone else pointed out):

> the Earth deviates from spherical by only a third of a percent, sufficiently close to treat it as a sphere in many contexts (https://en.m.wikipedia.org/wiki/Figure_of_the_Earth)

For most of what most of us do with our everyday lives it's good enough, to the extent that pointing out that "the earth is not actually a sphere" just sounds pedantic.

It did occur to me that sailing in a straight line could be interpreted as an actual straight line, but the surface of the ocean is spherical(fine, -ish) and so, modulo waves, we might actually be measuring an infinitely small distance on the earth that was sailable (Ah ha, got you all!) but realised that jokes about derivatives, despite the crowd, weren't going to be all that amusing :)