How far can human eyes be?

The vision of the human eye can extend as far as the horizon. If the Earth is flat (not the present sphere), you can even feel the light hundreds of miles away and at night, you are perfectly capable of seeing a flaming fire. flare up with a distance of up to 48km.

The vision of the human eye can extend as far as the horizon

How far can human eyes be?The answer depends on how many light particles or photons the object emits, the more likely it is to stimulate the retina in the eye. The farthest object visible to the naked eye is the Andromeda galaxy, which is amazing because it is located 2.6 million light-years from Earth.

Back in 1941, vision researcher Selig Hecht and colleagues at Columbia University conducted an experiment to examine the 'absolute threshold' of vision under ideal conditions. Volunteers are given a certain amount of time to fully adjust their eyes to the dark.

The flash of light acts as a stimulus with 510 nanometers (cyan blue) - the wavelength that most easily affects the eye, and this light is directed at the periphery of the retina. Scientists conclude that the human eye can see the weak glimmer of a candle at distances of up to 30 miles.

But in order to feel that glittering light, it must stimulate at least two adjacent cones - the type of cell that identifies colors. And so, for example, at a distance of 3 km, we completely see two separate headlights of a car.