how far can the eye see?

[spk]

When I look at the sky, or out to sea how many miles away from me can I see? Sorry if its the wrong section
Thanks !

[Quizmonster]

If you're standing at the water's edge, the horizon is about 3 miles away. If you click here, that will link you to a web-page which has a handy computer version that helps you work it out. All you do is put the height of your eye relative to the water's edge into the slot and click on 'Compute'. So, if you're eyes are 5 ft 6 inches above the ground - ie 5.5 ft - put that into the slot. If you are standing on a 100 ft cliff, put 105.5 in.

As for looking into space, you can obviously see as far as the furthest-visible star/galaxy...ie multi billions of miles away!

[CT]

If you're looking into the night sky, it's not how far you can see, it's how faint you can see. If you have perfect eyesight and look out on the clearest night, the furthest object you can make is probably the Andromeda galaxy. This is about 2 million light years distant.

[Clanad]

However, if one were to view a clear blue sky with no other features on which to focus, such as clouds, birds or other objects, the eye wouldautomatically focus at about 30 inches or so. This is called the resting point of accommodation (RPA). That is the distance at which the eyes focus when there is nothing to focus on. This especially true in total darkness...

[spk]

Thank you !

[Quizmonster]

After CT's reply, I should point out that a light year is the distance light travels during the course of a year...and it travels at some 186,000 miles per second! So multiply that by 60 to get the minute distance and 60 again to get the hour distance and 24 to get the day distance and 365 to get the year distance. I can't be bothered doing the arithmetic but I imagine it will fit my earlier answer of "multi billions of miles".