this post was submitted on 11 Apr 2025
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Science Memes

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[–] [email protected] 100 points 1 week ago (12 children)

The reason Legolas can see that far is because the curvature of Earth doesn't exist for elves. It is the same reason they can sail off into the Undying Lands without circling back around.

[–] [email protected] 54 points 1 week ago (1 children)

If you get 50m above the ground and have nothing in the way, you can see 5 leagues away as well. Good luck counting individual people from that distance though. The anime eyes are a necessity

[–] [email protected] 12 points 1 week ago (1 children)

That, or he’s got absolutely bonkers retinas that have truly incredible sensory density, and an absurdly developed visual cortex to support it.

Argument basis: DSLRs. Compare the detail you can extract from a 1MP sensor to a 100MP sensor, shooting through the same optical setup at the same target.

[–] [email protected] 31 points 1 week ago (1 children)

I think the pupil size calculation is based on defraction, so it doesn't matter how dense your retina is, if your pupils are smaller than that you still wont see enough detail. This is one of the reasons why we keep building bigger telescopes and especially telescope arrays. The bigger the effective apeture, the finer the detail it can resolve.

[–] [email protected] 9 points 1 week ago

Honestly, I’m waiting with bated breath until we as a global society can get our shit together enough to create a massive system-wide observation cluster. The shit we’ll learn from that will undoubtedly be incredible. I want my fully automated post-scarcity hedonistic space communism society. But I guess we have to get through the Great Filter first :/

[–] [email protected] 39 points 1 week ago (2 children)

even if you ignore curvature you have a resolution limit that depends on the aperture. Look up Rayleigh criterion for more info

[–] [email protected] 13 points 1 week ago (1 children)

But does it consider magic?

[–] [email protected] 9 points 1 week ago (4 children)

That would fall under "nonvisual perception"

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[–] [email protected] 6 points 1 week ago* (last edited 1 week ago) (3 children)

Except that this problem doesn't specify distance between horseman, so I think it's a bit bogus


no need to resolve an individual person to be able to tell that they're there. And for hair color, if you make assumptions about the clothes being worn, you could perhaps infer color of hair, even if the hair isn't resolvable (a person being a "single pixel" would have a different hue depending).

[–] [email protected] 15 points 1 week ago (1 children)

So, a typical pupil is around 2 mm in diameter in bright conditions. With the Rayleigh limit that results in an angular resolution of 1.22 * 60010^-9 m / 210^-3 m = 3.66*10^-4 rad

At a distance of 5 x 3 mi = 15 mi = 24.1 km this corresponds to a point to point distance of

tan(a/2) = (d/2)/l

d = tan(a/2) * l * 2 = tan(3.66*10^-4) * 24100 * 2 = 8.8 m

So in conclusion, with regular, human-like eyes he could discern points that are at least 8.8 m apart in the best case scenario. Discerning hair color from the color of the clothes would need a much higher resolution, and the horsemen are probably not 10 m apart from each other either. And again, this is a theoretical limit, real-world resolution would probably be significantly lower.

[–] [email protected] 10 points 1 week ago

which is why legolas has huge anime eyes

[–] [email protected] 6 points 1 week ago

That's part of the "make appropriate estimates" bit. You can just pick any reasonable number for the angular resolution Legolas needs and answer the question using that. Provided you do the method right, you'll get the marks.

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[–] [email protected] 21 points 1 week ago (1 children)

Didn't Middle Earth lore say the Earth was flat, but was made spherical later? Had that happened by then?

[–] Revan343 39 points 1 week ago (3 children)

Yes, but it's not spherical for the elves, just the other races, which is why elven boats can sail to the undying lands, but human boats can't.

[–] [email protected] 17 points 1 week ago (2 children)

Wait, is it the boat that ignores the spherical attribute or the entity that commands the boat?

Can an elf sail to the undying lands commanding a human built vessel?

[–] [email protected] 20 points 1 week ago

I think you have to be an elf building a ship and convince each plank individually that the world is flat

[–] [email protected] 9 points 1 week ago (2 children)

It's neither, it's the Will of Eru Illuvatar that determines whether you can travel the Straight Road or not. Ælfwine travelled the Straight Road and landed at Tol Eressëa in 869AD after fleeing the Danes, and he was a Man, not an Elf.

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[–] MajorMajormajormajor 14 points 1 week ago

Eru damn tangential elves flying off into space.

[–] [email protected] 9 points 1 week ago

This gives strong "Lovecraft describing things he doesn't understand as noneuclidian" vibes.

[–] [email protected] 6 points 1 week ago (1 children)

You mean the curvature of middle earth, right? RIGHT?!

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[–] [email protected] 56 points 1 week ago (1 children)

If anyone was looking for the exact quote its from The Two Towers, Chapter 2 "The Riders of Rohan".

“’Riders!’ cried Aragorn, springing to his feet. ‘Many riders on swift steeds are coming towards us!’
“’Yes,’ said Legolas, ‘there are one hundred and five. Yellow is their hair, and bright are their spears. Their leader is very tall.’
“Aragorn smiled. ‘Keen are the eyes of the Elves,’ he said.
“’Nay! The riders are little more than five leagues distant,’ said Legolas.
“’Five leagues or one,’ said Gimli; ‘we cannot escape them in this bare land. Shall we wait for them here or go on our way?’

[–] [email protected] 14 points 1 week ago (1 children)

So 5 leagues wasn't even the limit for him, he could have discerned their hair color at an even greater distance.

[–] [email protected] 12 points 1 week ago (1 children)

I like the "lucky guess" theory. He's bullshitting them.

[–] [email protected] 16 points 1 week ago

His thought process was probably "we're gonna run away anyways, I'm gonna tell these idiots I can see their hair color lol"

[–] [email protected] 46 points 1 week ago (3 children)

Some rough calculations:

5 leagues ≈ 15 mi ≈ 24.1 km. An average human has hair that's maybe 20 cm wide. Using the small angle approximation we get an angular size of 0.2/24100 ≈ 8.3x10^-6 radians.

At 400 nm wavelength, resolving details of that angular size requires an aperture of 1.22(400 nm / 8.3x10^-6) ≈ 5.88 cm.

So either Legolas has some absolutely massive eyes, has the ability to use both his eyes for optical interferometry (I'm voting for this since it's the coolest), or is just plain magic.

[–] [email protected] 7 points 1 week ago

There's magic in this world, it's possible elf sight is slightly magical.

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[–] [email protected] 32 points 1 week ago

I feel it is very important to post this here:

[–] [email protected] 32 points 1 week ago (10 children)

He has very strange-looking ears as well so I don't see the issue.

Also, take that, people who were whining about artists drawing manga-style LotR fanart after the Peter Jackson movies.

Anyway, does Legolas' ability to see very far necessarily mean his pupils must be humongous? The pupils on eagles aren't exactly very large either but as a cursory internet search tells me their internal structure is very different from human eyes. Anyone able to speculate on elvish eye anatomy?

[–] [email protected] 22 points 1 week ago (4 children)

Your pupil is functionally the same as the aperture on a camera. Whenever light passes through an aperture, there is some diffraction that happens to it; the angle of the light changes. This is separate to anything the lens does. If there's too much diffraction, you won't be able to tell two different sources of light apart. The amount of diffraction depends on the wavelength of the light and the size of the aperture. Bigger apertures and shorter wavelengths diffract less. This "diffraction limit" has a formula accordingly.

So for the question, we make some basic assumptions: take the wavelength of red light as it's the longest wavelength for visible light, and assume he needs to be able to tell apart two light sources 2 metres apart at a distance of 15 miles to distinguish individual riders. We figure out the angle between two points 15 miles away and 2 metres apart and now we know the angular resolution necessary. We know that the diffraction limit of Legolas' eyes has to be at least as small as that resolution. We also know our wavelength, so we can stick those into the formula and find out the minimum aperture (ie, the minimum diameter of Legolas' pupils to make out the riders at that distance)

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[–] [email protected] 13 points 1 week ago

I don't know enough about eyeballs to be able to answer, but 5 leagues is a bit more than 5x farther than eagles can see, and eagles already have larger pupils than humans do.

[–] [email protected] 6 points 1 week ago* (last edited 1 week ago) (1 children)

Yes, the ability to see very far away does imply in very large eyes if you define "see" by properly focusing on the objects. But not large pupils, what matters is the size of the eyes lenses, on the bare front of them.

But no, he could be able to perceive those stuff without the larger eyes if he had a good mental model of how the horsemen interfere with the background (what is probably easier than it seems, because they would be moving), and how their hair would interfere with the previous outline.

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[–] [email protected] 8 points 1 week ago

Middle Earth is flat. When they sail to the Undying Lands, they actually just fall off the edge.

[–] [email protected] 7 points 1 week ago

With coherent detection I think the separation between eyes would allow for this.

[–] [email protected] 7 points 1 week ago* (last edited 1 week ago) (1 children)

Not science (but related to huge eyes) but I recently learned that in The Sims 2 you can push the body control sliders to their max, hit a button to normalize the sliders while keeping your changes and then max out the sliders again, so you can do shit like give your sims Galaxy sized eyeballs.

[–] [email protected] 6 points 1 week ago

i remember doing this to make a sim with a nose the size of a car. I named him Nostrildomus.

[–] [email protected] 6 points 1 week ago

Remember kids: it it uses US American rando units, it’s probably not science!

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