he human eye is an extremely sensitive organ that can see great distances. Due to the specific surface of the Earth, our vision capacity is limited to 3.1 miles, 5 kilometers.
However, if the Earth were flat and a human being was standing on a high place, such as a mountain, they would be able to see for hundreds of kilometers. According to experts, the human eye could see the flame of a candle on a dark night at a distance of up to 48 kilometers, or 30 miles.
The distance at which the human eye can actually see is based on the photons, or light particles, emitted by a particular object. Thus, the furthest object that can be seen by human beings without any special equipment is the Andromeda galaxy. The distance between the Earth and the galaxy is 2.6 million light years. We are able to see it because of the thousands of photons emitted by the stars in the galaxy.