but on a more serious note...
I have run elevation and topo on miles and miles of lake front for development surveys. I have never seen a curve.
I'm not saying the earth is flat ... it's big ... but how far would I have to run a level before I see the curve?
I have even thought of just starting on a beach some where and running till I see it. Has any one done that?
And while we are on fringe questions ...
if I take a picture on earth with the moon behind me , it's a little ball in the sky .. right?
If I take a picture on the moon with the earth behind me, shouldn't it take up most of the sky behind me?
Some things just seem a bit out of wack .... I'm sure it's just me, but sometimes it makes me wonder?
Just go to the ocean, and watch a tall ship go beyond the horizon.
The bottom of the ship disappears as it follows the earth's curve, the top of the ship is the last you will see.
Of course, you need very good visibility to see it for the roughly 10 miles or more, because of local conditions.
Remember, surveying instruments use gravity to determine level. A bubble level at the equator and at the North or South poles will still show level, even though they point 90 degrees from the equator to the poles.
The horizon line is the curve. So of course you’ve seen it. You just didn’t realize it.
We’re only about 4 times bigger than the moon. And of course the distance is the same. So the earth is a larger part of the moon’s sky than vice versa, but not most of the sky larger.
Some fairly easy trigonometry can answer that question. The vertex angle of an isoceles triangle is given by 2 * arctan(b / (2*h)). "h" in this case is about 250,000 miles (distance from the earth to the moon), and b is about 8,000 miles (diameter of the earth).
Plug the numbers into the formula and you see that, looking at the earth from the moon, the earth would have an apparent diameter of 18.2 degrees, which probably isn't very close to "most of the sky".
Ever wonder why section lines do dog-legs?
but on a more serious note... go down to any ocean beach and watch the ships come up over the horizon.
Go to the beach at your local ocean and look at the horizon...