Respond to flat earthers by correcting their math
I literally just did the math on the first pic and it sinks 332 meters (~1100 ft) below the horizon which means it's only visible because of the mountains
3959-3959cos(81/25000*360/2) for the answer in miles
Google is in radians so if you check using google convert the part in the brackets to radians
The firmament was the source of the water from the great flood from the bible. That water drained to beneath the tectonic plates. Search "water beneath earth's crust"