- Dave referred to Samuel Rowbotham, who in the semi-distant past placed a telescope just 15 cm above the water of a canal and a boat at its end 10 km away. The boat was visible, so Samuel Rowbotham came to the conclusion that the Earth is flat. A calculation determines that at a height of 20 cm above sea level, the horizon is 1.6 km away. That is, objects longer than 1.6 km begin to disappear, being hidden by the curvature of the Earth. The problem with Samuel Rowbotham's experiment is the placement of the canal. To be a channel, the water must flow, so a slope that does not follow the curvature of the Earth is needed. The height of the boat, which should have been 15 cm, is also very important. The experiment would have been relevant if it had been conducted over a stretch of water like an ocean.
- The argument of the horizon in favor of a flat Earth is that it is right, if you look at it from the window of the plane flying at an altitude of 10,000 meters. We know from geometry that the arc of a circle is made of straight lines. So it is impossible to see the curvature of the planet if you look down. The pilots of the X and U2 military planes reported that the height from which the curvature is easily visible is 18,000 meters.
Radar Fundamentals