Calculating the curve of the Earth is so easy that even the Greeks figured it out millennia ago. The mass of the Earth was closely measured a few centuries back as well. Anyone still claiming that the horizon is not curved has either never been atop a tall mountain or out to sea. Hell, if it's flat you should be able to see the opposite shore of the great lakes with a telescope on a clear day even. Meanwhile our entire country and planet are being stolen out from under us while you're splitting hairs over geology.

Anyhow if Flat Earth was legit it'd be banned from YouTube along with vaccine injury and masks don't work.