Nice video, look I can't fault the person who made it - I'll assume they are honest. For anyone who doesn't understand what light does at the edges of the horizon it can be very appealing. Sadly it has an easy explanation. You can dismiss it all you like but it is exactly what is going on. Refraction. If you look at how the Buoy varies in what is behind it, that should give you an inkling of how temperature and air density affect light. The problem is YOUR understanding.   Your video: