Eyes

[aimee]

I know we can see galaxies far away, but that is emitted light. How far can the eye see in terms of horizons. If you were standing somewhere completly flat, how far can you see? Also, how far can you see out to sea?

[incitatus]

um..light is light. If you are standing somewhere completely flat (as in on not on a planet) the answer is still the same, provided the light reaches your eyes you can see it. Do you mean resolution? as in the ability of the eye to separate two objects? this is strongly distance variant. As is stereoscopic vision, which is basically usless for humans above about 100 yards. the horizon question depends on the height of the observer and the height of the object. essentialy the distance in nautical miles at which something is observable is given by 1.23xSQRT(height of observer + height of object) with heights in feet.