Earth
Flat Earthers want to reach the edge of the Earth. Pictured: Excellent view of the docked Apollo 9 Command/ service Module and Lunar 'Spider' with Earth in background, during astronaut David R. Scott's extra vehicular activity on the fourth day of the mission. Scott, command module pilot, is standing in the open hatch of the Command Module pilot, took this photograph from the porch of the spider. Getty Images

Flat Earthers will go on their “biggest, boldest, best adventure yet” aboard a cruise set to sail in 2020, but there's a catch. They might have to use a navigation system based on a model that goes against their belief.

Flat Earthers, or people who believe that the world is flat, will be embarking on a cruise to test their assertion that the Earth is a flattened disk surrounded by "an ice well barrier" or Antartica. According to the Flat Earth International Conference (FEIC)'s website, their planned journey will happen in 2020, and it will set sail to the edge of the planet.

The FEIC is not alone in this. The Flat Earth Society, supposedly the world's oldest official flat Earth organization, previously claimed that “the space agencies of the world” are part of a conspiracy that fakes space travel and exploration. The organization said that because of the USSR and USA's obsession to beat each other, they resorted to faking their accomplishments.

Nonetheless, those who will be aboard the FEIC's cruise ship will also get to enjoy swimming pools, restaurants and even "an artificial surf wave." Despite the organization saying it would be their best adventure yet, there is a problem. Cruise ships and similar vessels come with navigation systems based on the principle that the Earth is round.

Henk Keijer, a former cruise ship captain who sailed across the globe throughout his 23-year career, explained how ships navigate based on this principle. According to him, nautical charts were created with the idea that the Earth is round. He added that the existence of the global positioning system or GPS should be proof that the world is round not flat. The curvature of the Earth is the reason why GPS uses 24 main satellites to provide positional and navigational information.

He also said that if the Earth were flat, then it would only take three satellites to provide positioning information to everyone. However, that is not the case. It would take at least three satellites to identify a position. More than two thousand years ago, ancient Greeks already claimed that the Earth was a sphere. Gravity prevents everything from flying off it.