False: Radar beams and radio waves traveling straight and helicopters landing in the same spot prove that the Earth is flat.

Context

A video from Rob Taylor, a Flat Earth conspiracy theorist and military pilot, has recently been circulating on platforms such as Facebook and TikTok. In the video, Taylor claims that the earth is flat. To support this conclusion, Taylor claims that radars use radio waves that travel in a straight line and do not adjust to the earth's curvature. He further comments that if the Earth were spinning, a hovering helicopter would land in a different place because the ground beneath it would move.

In fact

The Flat Earth theory has been debunked countless times and has no basis in scientific evidence. The claims in the video fail to account for certain aspects of radio propagation and laws of motion.

The claim that radar and radio waves always travel in a straight line and do not adjust to the curvature of the Earth is false. As mentioned by Encyclopedia Britannica, radio waves in atmospheric propagation can curve due to ray diffraction, which allows them to curve around hills and objects. Radio waves are also bent and reflected off the ionosphere, allowing global radio transmission. The waves do not need to travel in a straight line and instead curve, bend and bounce off the ionosphere allowing them to travel around the curve of the Earth. 

Furthermore, scientific research has addressed the effects of the earth's curvature and atmospheric propagation on radar and radio waves. For example, a 2013 research paper by Sandia National Lab published through the U.S. Office of Scientific and Technical Information discusses that atmospheric refraction and the earth's curvature affect radar beams. The radar signals bend due to propagation effects from the atmosphere and often bend towards the earth like a lens. The paper also mentions that many radar systems already account for the curvature of the Earth.

The claim about helicopters also misunderstands the force of the earth's rotation. As explained in a Forbes article based on a Quora response by Robert Frost, an instructor and flight coordinator at NASA, the atmosphere rotates with the Earth. This means that everything in the air also moves at the same speed as the Earth. Therefore, when a helicopter hovers, it moves with the atmosphere and air around it, landing in the same place. The article further states that based on Newtonian laws of motion, for an aircraft not to move at the speed of the Earth, it would require another force that negates this speed. If such a force existed, it would act upon you when you jumped, and you would land elsewhere as the ground beneath you moved. This clearly does not occur, meaning that everything on the planet is moving at the same speed as the Earth.    

The verdict

Radio waves bend as they reflect off the atmosphere or ionosphere, and the atmosphere moves with the Earth. There is no evidence to support the earth being flat. Therefore we have marked this claim as false.