I went down the flat earth rabbit hole recently because I was certain that these people were not serious, but quickly realized that they are deadly serious. Flat earth Dave is an ass and loves to say how totally stupid it is to believe we live on a globe. I wish I had the science to definitively refute him (he has an open offer of 2 BTC for anyone that can give undeniable proof of a globe)
One of their favorite arguments is that “water always finds its level”
A quick example: the "White Nights" phenomenon in St. Petersburg, Russia, from late May to mid-July (peaking around the summer solstice), when the Sun barely sets, and the sky stays bright all night.
You already know why: the Earth is a sphere tilted on its axis. St. Petersburg sits way up north, around 60° latitude, so when the Northern Hemisphere tilts toward the Sun, its rays hit northern latitudes at a really shallow angle, almost skimming the horizon.
That shallow angle means sunlight travels farther across the atmosphere and along the Earth’s surface, instead of coming straight down.
Move a bit south to Berlin (at 52° north), and the Sun drops fully below the horizon at the same moment.
If someone were observing from each city, they’d see completely different skies at the same time: Berlin dark, St. Petersburg not so much.
The way daylight changes gradually as you move north or south, from quick sunsets near the equator to the long, glowing “white nights” near the Arctic is all the proof you need that we live on a tilted, spherical planet.
This latitude-dependent variation in daylight is impossible on a flat Earth....
