Elves in LOTR have technically infinite vision because the world used to be flat and illuminated by two glowing trees that resided in Valinor. Because the world was flat, and Elves have essentially perfect vision at any distance, they could actually see things that were on the opposite side of the world.
After Morgoth (aka Melkor, aka the evil god that Sauron worships) and Ungoliant (the mother of Shelob, the spider that nearly kills Frodo) destroyed the trees then the world was made into a globe and Elves infinite vision ability, while still useful, wasn’t quite as powerful as before.
So no they can use sign language to talk to someone on another planet of some other star?
Hmm. That should allow us to estimate the size of that world. The light of the trees must not be so bright as to cook everything in the vicinity; just make it nice and balmy. But, on the opposite side of the world, there must still be enough light to see. Having the occasional photon bounce back would eventually be enough to make out a static scene, but, apparently, it’s possible to see things happening in real time, yes?
Does flat mean that we are talking about something like a simple disc here, or just that a beam of light travels parallel to the ground? The latter would imply a rather strange geometry, which I can’t wrap my mind around. It would make more sense, though, as, obviously, we couldn’t assume that light intensity diminishes with the {ETA:] square of the distance.
It was a disc and the trees were able to be interacted with face to face so I think those are inexplicable except for “they’re magic”.
There’s a wikipedia article with some depictions actually right here: https://en.wikipedia.org/wiki/Two_Trees_of_Valinor#Creation
I have no intuition for how hot or bright these trees would be. They certainly would be very different from the sun. The sun is literally incandescent; white-hot glowing. Trees would presumably use a mechanism comparable to glow-worms to generate radiation only in a very narrow frequency band. The fair skin color of elves suggests that they do not come from a high-UV environment.
Somewhat less than half of the sun’s energy reaches us as visible light (43%). There are a few other factors that might allow the trees to glow brighter than the equatorial sun at noon. Unfortunately, the intensity per area diminishes with the square of the distance, so that doesn’t get us far (no pun intended).
It would be much better if that world was basically rectangular (with reflective sides and top); basically a terrarium. That would also explain why you would place 2 light sources at 1 end. The length of a long rectangular box would only be limited by absorption of the light. The trees should glow brighter at the top. Plants, animals and structures on the surface, near the trees, are hit with only “mild” power, while the high-intensity light near the top of the box is absorbed or scattered by the atmosphere over a long distance. I’m not sure how to work out how long such a box might be. Mainly, I don’t know what assumption to make about that high-intensity light at the top.
Anyway, we should consider that elvish anime eyes originally evolved as an adaption to low-light environments and only later became useful for seeing over long distances, because originally there possibly were no long distances.
they could actually see things that were on the opposite side of the world.
But there’s mountains and slopes and all.