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In my story, the character will walk to a space elevator he can see far away, but the question is "from how far away can he see his destination"?

The action is happening is inside a gigantic ring of mountains, with all land between the mountain and the elevator being almost perfectly flat and at sea level. How far could the bottom of a mountain be for you to still see the elevator?

The size of the shaft can be what you want to make the visibility better, as long as it is always of the same width.

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    $\begingroup$ If you don't care how thick the cable is, just make it as thick as you need to see it from as far as you need. You seem to be asking for two competing numbers, the unknown distance at which you can see a cable of unspecified thickness - if the latter can be anything you want, so can the former. $\endgroup$
    – Nuclear Hoagie
    Commented Mar 12 at 14:15
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    $\begingroup$ im more concerned about how curvature would play against visibility. $\endgroup$
    – shas
    Commented Mar 12 at 14:17
  • $\begingroup$ No amount of atmosphere will completely block visibility of a sufficiently large object-- note that you can see the moon even at the horizon. The other question is whether or not your elevator has obstruction lights. $\endgroup$
    – Jay McEh
    Commented Mar 12 at 14:23
  • $\begingroup$ it is earth sized, but not earth. the point is not to hide the structure but to see how far can i drop my protagonist and he would still be able to see it $\endgroup$
    – shas
    Commented Mar 12 at 14:27
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    $\begingroup$ I'm also going to vote to close as a duplicate, but to be practical, I'm not 100% happy with the original question from 2015. The original question is ambiguous about the construction of the elevator and this question is even worse. @shas, If you want this Q to remain open, you need to explain specifically why the earlier question doesn't meet your needs. Note that if you can, as written I'd vote to close as needing more details. You need to describe the construction of your elevator with specific details. $\endgroup$
    – JBH
    Commented Mar 12 at 18:51

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That depends on:

A) albedo:

How much light does the object reflect and how much do you count a slight shadow racing over the landscape as "seen".

B) brutalist sideeffects:

Megastructures leave a effect on weather patterns. Even if you can not see the space elevator, you can see the disturbed weather along the equator. Stackeffect https://en.wikipedia.org/wiki/Stack_effect and Airpressures: https://en.wikipedia.org/wiki/Wind_engineering - add to that significant iceloads and ice shedding..

C) competition:

Where there is one space-elevator, there is a power imbalance among governments on any planet. So, other governments build similar mega structures. So usually - there are several or similar ones like Skyhooks - Launchloops etc.

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About 6,000 miles

A geostationary satellite can see over 40% of the earth's surface and vice versa. A space elevator's counterweight orbits even further away and can see even more of the surface, approaching the limit of 50% the higher the orbit.

Basically, if you are almost anywhere on the same side of the planet as the space elevator (i.e. within the hemisphere centered on the elevator), you'll have line-of-sight to some part of it. So long as it's big and bright enough, you'll be able to see it (note that this is a big conditional, there may not be much reason to make an enormous, brightly lit counterweight). Your character can be nearly 1/4 the circumference of the planet away from the base station and still potentially see the upper end of the cable - hope he brought a lunch for the walk.

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Half the globe can see it, at least at night when the elevator is lit up by sunlight. The height of the elevator — from ground to the counterweight at geostationary orbit — is 35 786 km.

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    $\begingroup$ @Pelinore half OF globe not half WAY AROUND globe. Do not mix measurments. $\endgroup$
    – k_z
    Commented Mar 12 at 14:26
  • $\begingroup$ @Pelinore is not nice to edit when get response. But for Your edit: Sure. geostationary satelites are visible in cone for around 81' wich means around 9k km radius from pinpoint - 18k km wide area. Full half globe is 10kkm and 20k wide. $\endgroup$
    – k_z
    Commented Mar 12 at 14:33
  • $\begingroup$ @Pelinore You can see that small pencil next to Your posts. It shows that post was edited and how many times. First was edited once and second 5 times. Do not lie. $\endgroup$
    – k_z
    Commented Mar 12 at 14:41
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    $\begingroup$ @k_z: "Geostationary satellites are visible in cone for around 81°": This is blatantly false. Geostationary satellites are not visible from the ground, at least not without a good telescope. And even with instruments they are only visible sometimes, when the observer is in the shadow of the planet and the satellite isn't. $\endgroup$
    – AlexP
    Commented Mar 12 at 14:56

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