Hi, it has been a while since I posted last time on this forum and this is probably my last question. On virtually every topic on this board some flat-earther questions the linear path of light. However, evidences of straight path of electro-magnetic waves are observable in every-day life. Namely, we can observe it simply by measuring shadows of some big non-transparent objects (eg. buildings, bridges, moon during eclipse...). Also, the functions of radars, GPS satellites, and almost every device that uses electromagnetic radiation depend on it. How do you explain them?