Being on a planet
i saw this joke a while ago on Twitter:
which made me think, what would that look like?
i really have no idea.
and I found this troubling.
there are some things that just seem to go through, over, and around my brain.
..and I can't feel an understanding of it.
for example, i understand addition, subtraction, multiplication in my bones.
i have a good sense of that.
but division is just something i can't feel.
i can do it, or memorize it, but ... it feels weak.
another example is an analogue clock.
i had a lot of sympathy for this man on a This American Life episode.
as a dementia sufferer, he had to re-explain how a clock works, in a very relatable way:
"it's the superposition of three types"
right?
the clock is a circle, that represents:
  • a minute (0 - 60)
  • an hour (0 - 60)
  • a half-day (0 - 12)
- at the same time -
you know? that really makes sense.
and in some way, it was the first time I really understood a clock.
  • why isn't there a week-hand?
  • why isn't there a month-hand?
  • why is it a half-day?
ok,
Understanding being on a planet:
this should be easy.
for one, Latitude and Longitude just seem to wreck with my brain
look closely:
Latitude
Longitude
latitude uses parallel lines that never meet.
longitude lines all meet.
they are completely different systems!
why isn't there a west-pole and an east-pole?
latitude, that's sensible:
there is an obvious center with latitude
the sun tilts up and down, over the year:
the equator is the sun-middle - It's between high-day, and low-day.
the sun nicely gives us a latitude system.
this is how we define North and South,
it's a right-angle of the sun-middle?
i mean, what's the furthest place you can be from the middle?
also, as an aside-
if you don't live between those blue lines,
you've never seen the sun directly overhead.
its always been slightly goofy.
likewise, the north star is not directly north.
in this way, you can know how close to the equator you are,
by how crooked that star is.
this is why latitude co-ordinates go from -90 to 90.
it's how far you have to crook your neck to see it.
at the north pole, it's right-up, all year long
if you go a few steps south of the equator
it's completely gone.
that one particular star was pretty helpful
for the british guys, and the greek dudes.
anyways, latitude - I can get behind it.
it's cool.
longitude, it's a nasty thing.
the sun won't choose a particular longitude, for us.
which is annoying.
we're constantly spinning through latitudes,
so it's hard to pick one.
they all seem pretty good.
it would be cool to go back in time, and pick the prime meridian.
I would choose the location
where it was noon, on Jan 1, 0 AD.
that would be my choice.
if Bethlehem is at longitude 31,
the opposite is this:
which is a little boring actually.
people chose london though.
actually, a trashy part of east-london.
another thing,
whatever you choose,
the opposite longitude gets screwed.
because timezones use them.
right.
it all makes sense, from this side..
lookin good!
keep going!
whaaa
the hours tick in both directions from London,
and when they meet, on the other side,
nobody knows what day it's supposed to be anymore.
..which is a nuts thing.
no matter what time it is,
it's always a 24 hour difference
at this point.
i can't believe they let this happen.
and nobody protested.

ok then since,
the sun is at a different place, every minute
and,
the sun is at a different place, every day.
could you locate someone on the planet,
yeah!
but not very-well.
there are a bunch of creepy papers on this.
you can calculate both position, and time,
- from an image with a horizon in it.
😬
1) you need one 'known dimension' in the image.
it could be, like a car.
2) you can calculate the sun from a shadow.
it can be indoors.
3) the further you are from the equator, the more confidence
because the sun moves more.
4) some papers use a known focal-length of the camera
just a triangle with many decimal places.
5) the year can be derived from the weather
historical weather is fair-game.
In 2018, the BBC claimed to determine the time of a military conflict in Cameroon,
within 8 days.
i call BS on that.
one the developers described their basic method here.
but they are otherwise light on explaining methods, software, and assumptions.