The term "ball-earther" is a pejorative term for someone who believes that the Earth is a sphere. The term is often used by flat-Earthers, who believe that the Earth is flat.
Flat-Earthers believe that the Earth is a flat disc surrounded by a wall of ice. They believe that the sun and moon are much smaller than they actually are and that they orbit close to the Earth. They also believe that gravity is an illusion and that the Earth is accelerating upwards at 9.8 m/s^2.
There is a large amount of scientific evidence that supports the spherical shape of the Earth. For example, ships disappear over the horizon, airplanes can fly around the world, and different constellations are visible in different parts of the world.
Despite the evidence, flat-Earthers continue to believe that the Earth is flat. They often cite religious beliefs or personal experiences as evidence for their beliefs.
The term "ball-earther" is often used in a derogatory way by flat-Earthers. They believe that ball-earthers are naive and gullible.
It is important to note that flat-Earthers are a small minority of the population. The vast majority of people believe that the Earth is a sphere.