this post was submitted on 11 Apr 2025
807 points (98.8% liked)

Science Memes

14160 readers
1964 users here now

Welcome to c/science_memes @ Mander.xyz!

A place for majestic STEMLORD peacocking, as well as memes about the realities of working in a lab.

Rules

  1. Don't throw mud. Behave like an intellectual and remember the human.
  2. Keep it rooted (on topic).
  3. No spam.
  4. Infographics welcome, get schooled.

This is a science community. We use the Dawkins definition of meme.

Research Committee

Other Mander Communities

Science and Research

Biology and Life Sciences

Physical Sciences

Humanities and Social Sciences

Practical and Applied Sciences

Memes

Miscellaneous

founded 2 years ago
MODERATORS
[email protected]
[email protected]
[email protected]
[email protected]
807
kawaiiiiiii (mander.xyz)
submitted 2 days ago by [email protected] to c/[email protected]
80 comments fedilink hide all child comments
 
you are viewing a single comment's thread
view the rest of the comments
[–] [email protected] 39 points 2 days 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 2 days ago (1 children)

But does it consider magic?

[–] [email protected] 8 points 1 day ago (1 children)

That would fall under "nonvisual perception"

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

What about magical visual perception?

[–] [email protected] 8 points 1 day ago (1 children)

I think vision would fall girly within the realms of physics. I don't know if you can justifiably call it visual anymore when it incorporates magic

It's like, if there's magic bow that launches arrows at a far greater rate than it normally would, would you say that the energy comes from the buildup and release of tension in the wood? There's another element there, which enhances the thing

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

Please don't fix the typo.

[–] [email protected] 4 points 1 day ago

Oh 😭 lmaooo

[–] [email protected] 5 points 2 days ago* (last edited 2 days 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 2 days 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 2 days ago

which is why legolas has huge anime eyes

[–] [email protected] 6 points 2 days 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.

[–] [email protected] 2 points 2 days ago

The only way this would make sense is if the horsemen are all riding next to each other, which would allow him to estimate the count based on the average width of one riding horseman. As soon as one is even partially in front of another, the 105 number breaks.