I am surprised how far our eyes could see if our earth would be flat. Land surface bend and disappears out of the field about 5 kilometers away from the observer. But our visual acuity reaches far beyond the horizon.
If the Earth was flat or we stand on the top of the mountain we would track even bigger areas, we would see bright light being hundreds of kilometers away. In the dark night, we could see candle flame even if it was 50 kilometers away.
How far can the human eye see, it depends on light particles – photons – emanating from distant objects. However, from what the distance we can see objects, which are not a quivering flame? That visible object will not be perceived as a point but as a dimensional structure. The light must irritate at least two adjacent conical cells of the eye – the items of our eyes, determining what colors we see.
Human-sized objects are perceived even from a distance of about 3 kilometers. For example, in such distance, we should distinguish if the car is with two front lamps or with one.
© Fortune, 2020
Do you wear glasses?