[xenon1977]

Hello,

I have recently heard about tfes and have one key question if I may and it's to do with the curvature of the earth.

If you stand in say Africa or Ireland or anywhere in the world where there is an opposite continent; if one were to use an accurate and powerful telescope, you should be able to see the coastline of the opposite continent.

If the earth was flat, then a telescope observation between continents would surely prove flat earth.

If the earth was round, then the opposite continent would not be observable due to the curvature of the earth; hence why we observe a horizon when looking out to see.

Why can't we conclude this entire theory with one single telescope looking east to west or west to east across a straight line ?

Best wishes,

X

[Mysfit]

Observations over a long distance are subject to all sorts of issues, even on a round earth.
For one, the air gets in the way, with particulates and water vapour making some images look silly. Mirages and whatnot.
Weather conditions and time of day also affect these, as does elevation.

The simple straight line is pretty wobbly without looking into other wiki topics.
The sinking ship effect is a good place to start... I’ll make a link
https://wiki.tfes.org/Sinking_Ship_Effect

[TotallyFlat]

Lengthwise lines go. That's what I was taught in the bunker

[TomFoolery]

Hello,

I have recently heard about tfes and have one key question if I may and it's to do with the curvature of the earth.

If you stand in say Africa or Ireland or anywhere in the world where there is an opposite continent; if one were to use an accurate and powerful telescope, you should be able to see the coastline of the opposite continent.

If the earth was flat, then a telescope observation between continents would surely prove flat earth.

If the earth was round, then the opposite continent would not be observable due to the curvature of the earth; hence why we observe a horizon when looking out to see.

Why can't we conclude this entire theory with one single telescope looking east to west or west to east across a straight line ?

Best wishes,

X

About the farthest we can see terrestrial objects is perhaps a hundred miles or so, on the best of days.

But still, the earth is supposed to dip down over 6500 feet in 100 miles. So if the earth is really curved as NASA says, a 6500 foot mountain 100 miles away should appear right at eyelevel  for someone at sea level.
(Actually, terrestrial refraction is supposed to cause things to appear higher than they are at the rate of 1 degree per every 932 miles.)

I got plans to photo document measuring alleged mountain dip at 75 and 100 miles since those seem to be two really nice distances.
Also got plans of measuring alleged horizon dip from up on a mountain.
Also got plans to check for horizon curve by holding up a taught string horizontally.

And since you asked about a simple straight line, I got another idea.
I can get 2km of slightly buoyant 100 pound strength floating fishline off amazon for $60. Right now the budget isn't any more cooperative with that than the weather.
But I intend to string this line out and stretch it to a hundred pounds of tension - just under the surface of a lake on a calm morning.

The if the earth is curved, the water should bulge up between the endpoints by about 3 inches.

This experiment is exceptionally interesting to me because it doesn't rely on atmospheric issues or any long-range optical properties. It's just the string and the water. And everybody knows water seeks level.