Flat-Earthers generally invoke "atmospheric magnification" to explain how the sun maintains its apparent size during the day. Basically, this is the assertion that the atmosphere somehow magnifies distant objects. As supposed proof, some people have offered videos of boats disappearing below the horizon. This video is a good example:
Source: https://www.youtube.com/watch?v=GpAGXpusAiQ
Here's a picture of the large boat at 1:00.

Notice that the boat is already below the horizon. Assuming a viewer height of 2 metres (=6.5 ft), I'd say that this ship is at least 10km (6.5 miles) away from the observer. 15 minutes later (around 15:00), the boat has almost completely vanished below the horizon.

If this ship moved at a speed of approx. 36km/h (typical for large container ships, according to this website), it would have travelled about 9km or 5.5 miles during that time. However, the top structures of the ship did not become smaller, even though perspective dictates that objects get increasingly smaller as they move away from the observer. I am fully aware that the apparent size of an object is inversely proportional to its distance to the observer. Still though, it seems counterintuitive that the size of this object remained constant throughout the video. Is atmospheric magnification at work here?
Source: https://www.youtube.com/watch?v=GpAGXpusAiQ
Here's a picture of the large boat at 1:00.
Notice that the boat is already below the horizon. Assuming a viewer height of 2 metres (=6.5 ft), I'd say that this ship is at least 10km (6.5 miles) away from the observer. 15 minutes later (around 15:00), the boat has almost completely vanished below the horizon.
If this ship moved at a speed of approx. 36km/h (typical for large container ships, according to this website), it would have travelled about 9km or 5.5 miles during that time. However, the top structures of the ship did not become smaller, even though perspective dictates that objects get increasingly smaller as they move away from the observer. I am fully aware that the apparent size of an object is inversely proportional to its distance to the observer. Still though, it seems counterintuitive that the size of this object remained constant throughout the video. Is atmospheric magnification at work here?