Over 2,000 years ago, the Greek philosopher Aristotle had the rather revolutionary notion that the planet was circular.
In his book On the Heavens, he wrote:
Again, our observations of the stars make it evident, not only that the Earth is circular, but also that it is a circle of no great size. For quite a small change of position to south or north causes a manifest alteration of the horizon.
Since then we've sent satellites, cameras and people into orbit around our planet - and despite the overwhelming evidence they have returned proving Aristotle's theory correct, there are still those who believe the Earth is flat.
Flat Earthers across the globe are convinced there's a conspiracy of information control.
One of them even makes some pretty catchy music.
Rapper B.o.B - who is responsible for hit single Airplanes - is raising money to send satellites into space to help 'find the curve'.
Presumably, he both mistrusts the hundreds of existing satellites already in orbit and misunderstands how an 'orbit' works.
Twitter user Tim Pastoor gave B.o.B. - aka Bobby Simmons Jr. - the idea.
@jbinning17 They're always asking for an experiment they can do from home, so here's one: Crowdfund a satellite and go look for the edge.
— Tim Pastoor (@email@example.com) (@Tim Pastoor (@firstname.lastname@example.org))
Actually that's a great idea. 💯💯💯 https://t.co/1obtdBZocH