Anyone who has entered into an argument with flat-earthers is bound to have heard phrases in the style of:
If the Sun is 150 million kilometers away, why do its rays look like they are flying apart, as if their source is much closer? This is especially noticeable in cloudy weather. After all, given the enormous distance, the photons from the Sun would have to fly almost parallel to reach our Earth, wouldn’t they?
I like this question, because it touches on an everyday phenomenon that probably every one of my readers has observed at least once in their lives, so I decided to write a short article on this topic.
The sun’s rays are not always visible to the naked eye. On a normal cloudless sunny day you will not see any individual rays, but if you could still distinguish them, you would make sure that when nothing is blocking the sunlight, its rays are strictly parallel
When sunlight passes through the Earth’s atmosphere, two scenarios are possible: sunlight either passes through the atmosphere without a significant change in direction, or it scatters and is directed in all directions simultaneously. We owe the latter effect to the fact that on days when the sky is overcast we can still see everything around us, even though the sun is hidden by clouds.
