It's a matter perspective; This has been explained before..........
Yes, you have shown this video before. No, it does not explain how sunset works on a flat earth.
I thought I would try to understand what is going on in this video as it seems to offer a plausible explanation - sort of. On looking at it again, there is a classic 'slight of hand'.
Summary: This illusion works by starting with the sun going around in a circle to going. Then after being distracted by explaining perspective, changes to a straight line and hoping no one notices this switch. (But even if the sun was going in a straight line, there are other reasons why that cannot work).
1) The YouTube video starts by stating that the sun is above the flat earth and moves around
in a circle at a constant height. Seems reasonable for a flat earth explanation. One 'minor' niggle: the area being lit up should be a semi-circle, with the middle of the straight section being approximately above the North Pole (centre of the flat earth). Not some roundish 'blob'. One of the graphics in post #2,431 (@lifesyop) gives this height at 3,100 miles. (This is not a random height, but is a possible alternative based on Eratosthenes calculations).
2) Later on, the video claims that the sun travels at over 1,000 mph. The equator is 24,900 miles in circumference, so for the sun to travel around the equator, it would need to travel at over 1,000 mph. About 1040 mph - but this would vary slightly throughout the year. So, this speed does make sense for a flat earth.
3) Next, the video explains in tedious detail how 'perspective' works. Again, this is a reasonable explanation. It gives several examples including several street lamps.
4) The video then applies perspective to the sun moving
in a straight line.
Note the subtle switch? From moving in a circle to a straight line.
5) But, the observant reader will cry, a short section of a circle will look light a straight line. After all, this is the argument that global believers use to explain why the horizon on a globe looks flat. So, is the OK - lets now look at scale. Is this straight movement just a short segment of the sun's circular movement?
4) The lamps on the street lamps shining down represent the sun. You need to imagine the street lights being 3,100 miles high. The distance from one lamp to the next is usually greater than their hight (if a lamp falls over, it will not hit the next). I'm going to assume that the distance between lamps is the same as their height (in practice, it will be more).
5) The various examples given have over 20 lamps (but still not at the vanishing point). So, the 21st lamp will be 20 * 3,100 = 62,000 miles away - at least..
6) The sun travelling 62,000 miles in a straight line contradicts the start of the video that claims it moves in a circle at constant height above the earth.
7) But lets keep going with the sun travelling further and further away so that perspective can explain why it appears to be close to the horizon. At just over 1,040 mph, it would take 3 hours to travel from one lamp post to the next (remember, the lamp posts represent the position of the sun). OK, to be exact, 44 seconds short of 3 hours - but that assumes the lamp posts are 3,100 apart - the same as their height (the sun is 3,100 miles above the earth).
What if the sun did magically switch to going in a straight line?
8) At midday, the sun is represented by the nearest lamp post. At 3pm, by the 2nd, 6pm, by the 3rd. On the equator this will be dust. But lets assume the summer in England. So, by 9pm, the sun will be at the 4th lamp post.
9) Now, it will have to move to at least the 20th lamp post to appear to be near the horizon. So, another 15 lamp posts. Or 46,500 miles.
10) Sunset takes about 2 to 5 minutes. This means the sun must move from the position of the 4th lamp post to at least the 20th in 2 to 5 minutes. So, an average of somewhere between over 500,000 mph to over 1 million mph. And the sun will still be visible.
11) Perhaps the atmosphere absorbs the light such that the sun cannot be seen a long distance before the 20th lamp post. If that was the case, then you would stop seeing the sun before it appeared to be at the horizon (due to perspective). So, if perspective explains the sun setting, you must still be able to see it at this big distance.
12) If the sun has zoomed off into the distance, far enough that perspective makes it appear to be at the horizon, then it cannot be overhead for areas 6 hours later time zone.
13) It does not explain how you can lie down and watch the sun set. Then stand up and watch the sun set again.
14) It does not explain how if the sun is setting for you, then for someone 1000 miles further East, it will be night time - no sun visible.
15) If the sun is a spotlight and daytime only happens for areas lit by the spotlight, then the point at which it changes from light to dark, the sun will still be overhead in the sky - it will not appear to be anywhere near the horizon.
Conclusion - perspective cannot explain sunset (or sunrise).
Does that make sense?