Despite there being no evidence that would suggest that the Earth is a flat disc floating in the middle of space they will not be deterred.
Even when they argue with actual scientists flat-Earthers remain convinced that they are right. But what happens when they are confronted with someone who has actually been into space and seen the planet in all of its spherical glory?
During a 2017 instalment of Good Morning Britain, one of the internet's most prominent flat-Earthers went toe-to-toe with astronaut Terry Virts. It was difficult to watch.
Mark Sargent, a conspiracy theorist from Seattle appeared on the show via a video link and attempted to argue his case.
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He told Piers Morgan, Susanna Reid and Virts the following: "I think the Earth is flat – go to the beach with a high-powered HD camera and look off into the distance. 10, 15 years ago, you could see ships go off into the horizon. Now you can bring them back into frame, all you need to do is crank up the zoom.
"Technology has changed everything. We’re talking about all the world is a stage. We’re basically living on a big sound stage and nobody figured it out until 1956."
Virt's evidence was a bit more conclusive.
The flat earth debate: Have NASA been lying to us for decades? @AstroTerry shares his theory 🌍… https://t.co/Cd2LeZuidd
— Good Morning Britain (@Good Morning Britain)
To rub more salt into the wound, Virts also produced a copy of his space photography book which clearly shows that the Earth is round.
Sticking to his guns, Mark dismissed the photos and claimed they had been doctored.
Virts later took to Twitter and clearly seemed to have enjoyed debunking this myth.
Matter settled. The Earth is round! Now on to bigger and more important issues.... @GMB #ViewFeomAbove @IMB… https://t.co/cLqyxwUrUr