That's been the true irony of this whole back and forth... Tom has been pointing out that the flat earth explanation for the way the sun sets does not and can not match observations. Just, over and over again, seemingly oblivious to it.

The crux of the argument is here:

* If the earth is flat then your objections to the diagram are entirely valid...and YOU need to explain to US what's wrong with it...because the only three assumptions it makes are:

a) The earth is flat.

b) Light travels in straight lines.

c) The sun is a long way above the ground.

Because (as you VERY correctly say) the diagram doesn't agree with reality - then one of those three assumptions I made when I drew it must be incorrect.

There's still the '3rd person diagrams can't model it correctly' cop-out, so I thought of a 1st-person way to model a sunset on flat earth. I don't have a diagram, for lack of preparation and resources, but maybe one can be made or found.

+ Lie down at one end of an infinitely long, very tall hallway. The floor and ceiling are perfectly straight, forever.

+ Directly above your head is a light fixture on the ceiling, 10 meters high. The viewing angle is 90 degrees, straight up.

+ Every ten meters along the ceiling is another light, identical to the first. The viewing angle decreases for each light in proportion to its distance away.

+ What are the angles from your eyes to the light on the ceiling that are 30m, 300m, and 3 km away?

+ How far along the ceiling is the closest light for which the viewing angle is 0 degrees?

For those paying attention at home, you will notice that this is the same exercise as the sideways diagrams, no surprise. But answering these questions will be revealing; the proportions of the "3000 mile high, 6000 miles away" sunset are met at the light that is two steps away, 20m out and 10m up, twice as far as it is high; the viewing angle is 18 degrees. For reference, try this at home: Find a doorframe that has two door-height-lengths available on the floor in front of it. Lie down on your back, so your toes are the horizon facing towards the doorframe, and your head is at the 2:1 position. Look at the top of the door... huzzah, it's an 18 degree viewing angle!

[I double checked my math - it's actually

26 degrees]

Anyway... the angle for 300 meters is 2 degrees, and for 3000 it is 0.2 degrees. And because light travels in straight lines, these proportions remain true. 10 up, 3000 away... 1:300.

So on a flat earth, in order for the viewing angle from the ground to get within a fraction of a degree i.e. close to the horizon, given that the sun is 3000 miles high, it must then be 900,000 miles away. How far away is Baghdad from New York, again?