Science Memes

15227 readers

1053 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

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

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

Research Committee

[email protected]

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]

fossilesque

859

kawaiiiiiii (mander.xyz)

submitted 2 months ago by [email protected] to c/[email protected]

94 comments fedilink hide all child comments

you are viewing a single comment's thread
view the rest of the comments

[–] [email protected] 106 points 2 months ago (38 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] 39 points 2 months ago (11 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] 6 points 2 months ago* (last edited 2 months ago) (4 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 months 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.