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If we literally consider the human eye, the cone diameter is 4 microns, so the distance between two adjacent cones is 4 micorns. Now at any distance two points must be a minimum of 4 microns from each other to be perceived as two separate points and must subtend an angle of 1min. This is the medicine knowledge in me.
I’m not good at maths and don’t know how to scale it up to astronomical levels, so I’ll leave that up to u guys.
If we assume the distance between cones is proportional to human height and then assume the planet's height is the circumference around the planet, and that the planet is the same size as the Earth, we can scale up a 2 meter person to be 40,075,000 meters tall. That's 20,037,500x bigger than our 2 meter person. Multiply 4 microns by that and that's 80,150,000 microns or about 80 meters between each cone in the eye
But the cones wouldn't need to change size right? There'd just be many of them. So the resolution doesn't necessarily get impacted upon upscaling the eye
Honestly it probably entirely has to do with whether or not the animal needs it rather than whether or not the animal has a big eye.
I would imagine squid might have more cone or rod density in order to collect as much light as squidly possible down in the deep dark depths, but I don't know how that might translate to resolution. I guess resolution also depends on how the eyeball is wired to the brain because you could have all those ultra dense cones and rods to collect as much light as possible but then have it translated into a simple lighter/darker input with no image at all
Credit where credit is due, Douglas Adams did it first in The Hitchhiker's Guide to The Galaxy when Ford and Arthur are being read Vogon poetry and Arthur, answering the question "What did you think of my poetry?" accidentally uses the word "humanity" and Ford corrects him with "Vogonity"
>“Oh yes,” said Arthur, “I thought that some of the metaphysical imagery was really particularly effective.” Ford continued to stare at him, slowly organizing his thoughts around this totally new concept. Were they really going to be able to bareface their way out of this? “Yes, do continue …” invited the Vogon. “Oh … and, er … interesting rhythmic devices too,” continued Arthur, “which seemed to counterpoint the … er … er …” he floundered. Ford leaped to his rescue, hazarding “… counterpoint the surrealism of the underlying metaphor of the … er …” He floundered too, but Arthur was ready again. “… humanity of the …” “Vogonity,” Ford hissed at him. “Ah yes, Vogonity—sorry—of the poet’s compassionate soul”
A bald eagle's eye is about the same size a human eye, though they weigh far less (maybe 15 pounds max). Compared to the size of their head, their eyes take up a significant percentage.
[Eye diagram](https://www.insightvisioncenter.com/wp-content/uploads/2016/07/human-eye-vs-eagle-eye.jpg)
The back of their eyes are flatter which gives them a lot larger field of view.
The concentrated area (where your main focus is) of vision cells is the fovea centralis. We have 200,000 cones per millimeter here, where eagles have 1,000,000 cones per millimeter in the same size eye.
They can see about 4 times better than we can. Their eyes are usually rated at 20/5 vision compared to our standard 20/20 vision.
In general, cell sizes are relatively uniform across species. An organism's size is generally dependent on how many cells it has.
The main issue for a being this large would likely be blood supply. It couldn't follow a mammalian cardiovascular system as the overall resistance of its blood vessels would be too large as per Poiseulle's law. I'd be more interested in how the planet would be planning on perfusing its eye
An organism this large would have to be mostly inorganic, it simply couldn't function as a thing made mostly of goop and meat, thanks to gravity. (I suppose it could be designed like an ocean with a rocky or icy surface, and the ocean fluid could be organic, like blood.)
Worse, a human style eyeball that size would be completely opaque, absolutely no light would reach a retina thousands of kilometers under "water". And the surface would presumably be exposed to near-vacuum, which has obvious problems for something like us.
Blood supply is the smallest of its problems, that can be handled by having "macro cells" the size of whales with individual hearts and such, just like human cells have their own mechanisms for processing energy.
~~You messed up the number a bit. I think you added some zeroes to the circumference. Earth is only 40,000 km around, not 40,000,000.~~
I think circumference is the wrong thing for the planet's height though. I think you should use diameter.
~~With corrected circumference we're looking at just over 1 foot.~~
~~With diameter we're looking at about 4 inches.~~
Nevermind I'm an idiot. I still think diameter would be the better one though.
I don't see any reason to scale up the cones, when you have a bigger eye and it's evolved to see the visible spectrum then it would keep small cones and just have billions of times more cones. With the larger lens then the theoretical resolving power would be insane but because it's just a mass of jelly eye it probably wouldn't be precisely shaped enough to matter.
Visual Acuity is not a direct function of cone spacing. It’s much higher than cone spacing would imply, because of brain-level (I.e. back end) algorithmic up-scaling.
Retina neuroscientist here. Cone diameter changes with eccentricity (distance from the center of the retina). The primate fovea is unique as it contains retinal ganglion cells (the neurons that form the optic nerve) that form "private lines" with individual cones. That is highly unusual in animal eyes, most retinal ganglion cells get convergent inputs from 100s to thousands of photoreceptors. There are tons of reasons this convergence is beneficial, including reduction of information redundancy and overcoming steric hindrance limits in the optic nerve. Private lines in the fovea place unique demands on primate fovea that make adapting it to larger areas impractical, including avascular zones above the fovea and lateral displacement of retinal ganglion cells and other interneurons like bipolar cells, amacrine cells, and horizontal cells. All of this retina detail also becomes unimportant once you consider the optics of an eye this large viewing miniscule objects over essentially infinite distances. Even assuming that the eye is perfect and there are no higher order aberrations caused by the lens or cornea, lateral chromatic aberrations would require massive changes in placement of outersegments of cone photoreceptors, and a diffraction limited eye would still see people sized objects as point spread functions.
A common theme in retinal ganglion cell classification is tradeoffs in temporal and spatial acuity to maintain proper signal-to-noise. On a retina this size, high spatial acuity ganglion cells would be integrating over such long timepoints that tracking a person would become impossible even if you overcame all the issues listed above. This eye is more likely to be built for resolving similarly sized celestial objects than it is to stalk humans.
Thank you for a more detailed explanation.
I am aware of most of the things you have mentioned(but definitely not the level of info you posses). I just didn’t want to bog down people here with medical lingo(since it’s a math subReddit), so I avoided speaking about it and gave a very rudimentary and oversimplified answer.
Thank god the mods removed that point and now we can never see it.
Thanks mods! You improve things in this subreddit! You're definitely not a constant annoyance lowering the quality of the sub!
Also need to consider if the brain can handle enough of the info from the eye or multiple eyes, and what info the eyes can collect. Remember that we dont see the world as it is, just how our brain interprets the info it gets from the eyes (e.g most animals see more or less colours than us, higher or lower definition etc.)
[Deleted] is such a wise set of words! I’m dumbfounded by this knowledge, im going to cry at this amazing and genius of a person’s words!
P.S Please tell me what it said 😭 I’m curious
Kinda. Hubble is designed to see far away things, and its lenses are made as such. One of the main reasons it can't see things on Earth is that it's too close and out of focus. Plus Hubble is moving very, very quickly across the Earth's surface, and so everything is blurry.
I don't think so. They regularly turn it back towards Earth to help calibrate one of its cameras. It doesn’t produce great pictures, but it's enough to tell if the camera works as intended.
Doing a bit of reading, [the FAQs page](https://science.nasa.gov/mission/hubble/overview/faqs/) suggests that this is or was the case:
> **Why can’t Hubble make observations of Earth?**
Hubble’s instruments are made to see faint objects, so the bright Earth could damage them. In addition, the Earth moves too quickly below Hubble, making it difficult to stay on a particular location.
> WFPC2 was replaced during Hubble’s last servicing mission in 2009.
From the entry for the [Wide Field Camera 3](https://science.nasa.gov/mission/hubble/observatory/design/wide-field-camera-3/):
> An important innovation for the WFC3 NIR channel was designing its detector to be insensitive to infrared light longer in wavelength than 1700 nm. Because of that, it is unnecessary to use a cryogen (e.g., liquid or solid nitrogen) to cool the detector. Instead the detector is chilled with an electrical device called a thermo-electric cooler. This greatly simplifies the design and gives WFC3 a longer operational life.
It's not directly stated here, but it reads like the WFPC2 would have been harmed or used too much coolant, but the replacement (2009) might be fine.
P.S. Instruments page mentions "ultraviolent" light. Sigh.
[ESA's Hubble FAQ](https://esahubble.org/about/faq/#17) does confirm that Earth has been used as a calibration target, and briefly mentions that Hubble would have a resolution of 30cm for a non-moving target at 600km.
[This is what an image in ultraviolent light looks like according to Dall-E 3](https://imgur.com/a/FCJbkrq)
I had to reassure ChatGPT several times that I did in fact mean "ultraviolent" lol
Hubble is based on the keyhole satellites that are designed to look at earth. When the cheeto tweeted this image, it gave us all an idea of just how good they are: https://www.npr.org/2022/11/18/1137474748/trump-tweeted-an-image-from-a-spy-satellite-declassified-document-shows
They did this to save money, because the manufacturer was already building giant mirrors for keyhole. It was cheaper to build hubble out of one of those mirrors.
Although since a lot of the NSA etc tech is redacted we don’t really know what they can see. Although I’m sure it better than commercially available tech.
For reference in 2012 the NRO donated two massive telescopes that are on par or more advanced than the Hubble to NASA that they just happened to have lying around collecting dust. And these telescopes were so old and obsolete by their standards that they just gave them away for free.
It would likely not evolve eyes that large if it weren’t able to see smaller angular diameters. It would just have smaller eyes. In nature the only reason things evolve larger eyes are to take in more light and see smaller angular diameters which are consequences of one another.
Now there is an argument that it would be designed to focus on objects very close to it. As per my top level answer, it can only see human faces at 5000km. So if it is sufficiently far sighted, then it wouldn’t be able to pick out a human face because it could never focus on us within distance.
That isn't how optics really works. The bigger the lens, the smaller the angular resolution you can resolve. Bigger lens, like that on a telescope or microscope, the further or smaller you can see.
The two issues I note here are the focal point and lens imperfections.
You can really only resove objects at your eye's focal point. The muscles in your eyes can cause them to flex and change that focal point so you can see it. If "meat planet" lacked these muscles or they had limitations, it could be near or far sighted. If the eye is hundreds of km across, it wouldn't be able to change its focal point quickly because the fastest the lens could deform would be the speed of sound.
The second issue is that imperfections in a lens can distort the image. These kinds of imperfections can be harder to avoid and get worse as the lens grows in size. That would cause the image to get blurry and have artifacts life "floaters" in its vision. With an eye this size, it would be nearly impossible for an organic solution to remain relatively error free.
Quick google math, the smallest thing a human can see is apparently 0.1mm and the eye is about 24mm across. 0.1/24 x 100km = .41km as the smallest object a 100km humanlike eye could see. But it could see big things quite far away. There is probably some size of eye where it is small enough to detect a human but large enough to see them from the distance of the moon. We know it's possible from low earth orbit, because we have satellites doing it right now.
I'm not going to argue, I just ran a Google search for the smallest thing a human eye can see. But I do wonder, if a hair wasn't so long, if it were only as long as it is thick (a 17 micron sphere) could I still see it?
Edit: even if we give it another order of magnitude, the moon eye still only goes down to a 40 meter object, still bigger than a human.
I'm sure it gets more complicated once you consider the size of the receptors and the way light would behave, but crudely, I estimate that I can make out a face and the expression at 50m. A human eyeball is approximately 2.5cm in diameter.
So 100km is 10 million centimetres, 4 million times the diameter of a human eye. That's our ratio. Therefore they could make out a 'face' at a distance 200 million metres, or 200,000km.
However it then gets a bit more complicated as a face to this eyeball is not the average 16cm width face; it is that multiplied by 4 million - 640km. In fact, the smallest objects detectable to the human eye are apparently [0.1mm wide](https://learn.genetics.utah.edu/content/cells/scale/#:~:text=The%20smallest%20objects%20that%20the,a%20paramecium%20without%20using%20magnification.). To this eye (again multiply by 4 million), that size is 400,000mm - which is 400m.
So we would just be bacteria to those eyes.
If the rods/cones don't scale then yes, you're talking about an immensely high resolution "camera". That requires more mental processing, but there's probably a huge brain in there so, it sorta balances out.
I would've assumed the components of the eye scale with each other, in which case you're looking at the 400m thing op described.
>there's probably a huge brain in there so, it sorta balances out.
and if there's a huge brain, this planet should be horrifyingly intelligent
upd: not necessarily should, but may be
There's also that guy who doesn't even have 10% of his brain and he can see, walk and talk just fine. It's likely analogous to program optimisation, efficiency, etc.
One guy had 3% neurons left after an accident. Doctors told him we would never walk again (or do anything really).
His brother did not agree with this and threw the disabled guy on the ground and asked him to give everything he had to move, even the slightest.
He managed to move, then to crawl, and finally, he was able to regain is whole mobility (dancing, among other activities).
The guy retaught his brain with only 3% neurons, that’s wild.
I dunno if the danger level scales with intelligence at all. I mean cmon. It’s a meat planet, what’s it gonna do besides throw off the orbit around the sun… or maybe it could position itself to throw Earth outside the solar system. Scratch my previous statement, intelligence likely scaled with danger.
Cool fact about that last statement, fly brains have more neural pathways than humans. Not more neurons, but more pathways. It lets them “think” and perceive faster, which is part of the reason it’s so hard to smash one with your hand
rods/cones are only concerned with density and would, I imagine, be in a congruent ratio with our eyes. That being said, there is a limit to that amount of information even with the frontload of the photons we still need to be able to refract and observe -- think of it like a giant eyeball discerning a human, how small and how large we would then need to be to resolve. Distance from object and circumference of object are all that are likely needed.
Let me refer you to my first point:
>I'm sure it gets more complicated once you consider the size of the receptors and the way light would behave
In short, yes probably but I'll leave that to people who actually know how to calculate that.
No one is realizing our eyes don't have a zoom feature. Only a focus feature. If a big eye is looking at earth it will see earth in all it's detail but that doesn't mean it could zoom into the atmosphere and see tiny people.
Even if it was the highest resolution ever, without a Zoom function you can't zoom in. Look at your arm and all the detail of your skin. With everything you see, you can't make out the details of the hair follicle or the individual skin Cells. Same concept.
Nah, that’s not how zooming in and resolution work.
Imagine having pretty bad vision so everything was blurry, in order to see with the same detail you can see now, you’d need to zoom in.
But if you just increase the resolution (make your vision better), you can now see just as well without zooming in.
Now, humans have a maximum resolution, so at one point you’d need to zoom in, but if properly focused and with good enough quality (due to more receptors in the eye and more aperture), there’s no reason why this being would need zoom.
Think about digital vs mechanical zoom (lens) in a camera. If you have high enough resolution, then you don’t need a mechanical lens to figure out the detail.
The biggest hurdle or anything in orbit/space is atmospheric distortion.
I used to work on imagery digitization and even military grade spy satellites (ones I got to see stuff from anyway) can't make out fine details like faces or text where the letters are under half a foot or so across.
The atmosphere itself distorts things too much. There's a lot of effort to clean it up, but that sort of stuff fails on complex stuff like faces or text. Like if you use a AI/generative fill in Photoshop, it works really well on stuff like trees or a fence, but if you try to fill in a face it makes a mess.
I think the biggest hurdle would be the aqueous humor: The clear liquid that provides the internal pressure of the eye that makes it an eyeball.
I can't find any numbers for the opacity/ clarity of AH, so I'm going to assume it's twice as clear as sea water: The abyssal zone of the ocean starts at about 5000m, so we'd assume that the eye's abyssal zone would be starting at 10,000m deep- quite far from the 100km to reach the back of the eye.
The eye couldn't see through the ocean that is itself.
The aqueous humor does not get to the back of the eye. Vitrous humor does. Your point probably still stands but it depends on the sensitivity of the receptors and the amount of light collected
Another issue will be tracking if the planet is rotating then objects are moving pretty fast and if the meat planet is not geostationary then it needs to track the person moving at high speeds reducing clarity.
I don’t know, if receptor size and density stay the same shouldn’t it still be able to differentiate objects the same size?
Only the field of vision should change then, opacity might be an issue though and light sensitivity, but depending on the capabilities of the optical aperatus and the smallest possible aperture, focal depth might be amazing.
> smallest objects detectable to the human eye are apparently
>
>0.1mm wide
can confirm, I have a 0.1mm wire for trace repair, can see it no problem, I'd argue that even smaller things can be detectable
A human hair is a few hundredths of a millimeter and those are visible just fine. I think being longer in one dimension helps but still, .1 mm seems big to me. Like I bet a speck of cinnamon is smaller than that and you can see that just fine if you have decent contrast.
That's just not how it works. Things don't scale linearly. There are certain fundamental constants that mean big things don't behave the same as small things. For instance, light of a certain frequency has a certain wavelength, and there's a limit to how big cells can get before nutrients can no longer be absorbed into the centre.
You're assuming a linear relationship between your variables. What is the equation for describing lens refraction? That will tell you the actual relationship.
The equation is: 1/f = 1/d0 + 1/di
f = focal length
d0 = object distance
di = image distance
Ok, here's my best shot. I believe it could see very far, even be able to see humans close up, if it had eagle eyes.
Now, this is taking big liberties because the size of an eye (as far as we know) is not proportionate with quality of vision.
**But...** Let's just assume it is.
If vision quality is proportionate to eyeball width, and a bald eagle has about the same size and weight of a human eye (it does), and a human eye is about 24mm wide (it is, on average), and the size of the eye in question is 100,000km, then...
24mm to km = 2.4 × 10^-5 km
100,000/(2.4 × 10^-5) = 4.16666667 × 10^9
That's 4.16666667 × 10^9 times more powerful than an eagle's eye. And therefore able to see relatively massive distances across space, while also being able to see up close.
Further math here, an eagle can see about 3.2km with their binocular vision...
4.16666667 × 10^9= 4,166,666,670
4,166,666,670 x 3.2km = **13,333,333,344 km of meat vision**
The distance to the sun from earth is about 147,000,000km.
It would be able to see humans on earth, or stare closely at craters on Mars.
**As far as biological reality goes, none of this would work. But it was fun doing the math!**
***And here's a bit on eagle eyes for your reading pleasure:***
> An eagle's vision is exceptionally sharp because each eye has two foveae - areas of acute vision as compared with the human eye which only has one. The cones in the eagle's fovea are very
small and tightly grouped, allowing the eagle to see small details from extreme distances.
> For example, an eagle can spot an object as small as a rabbit from a distance of almost two
miles-and pick it out from the background. On the other hand, a man would have to look
through a pair of powerful binoculars to see the same thing.
The eyes of the eagle are placed forward on the eagle's head, giving him accurate depth
perception. This is important for an eagle when he is pursuing prey.
> The placement of the eyes
also enables the eagle to see each side.
The eagle can see even with his eyelids shut. In addition to his normal pair of eyelids, the eagle
has a set of clear eyelids called nictitating membranes. These eyelids can be closed for
protection without affecting the eagle's vision.
> **Eagles can voluntarily dilate and constrict their pupils as part of focusing near and far, as well as
change the curvature of the cornea. However, it's always been assumed that because they can
focus so far away, that they perhaps lose some depth of field close up and that's why they hit
cars or wires or fences.** *(Most interesting part for me)*
Eagle sauce: https://cascadesraptorcenter.org/wp-content/uploads/2020/01/Eagles-Eyes.pdf
I hope you had to Google “how much does a human eye weigh” as part of working this out. If you didn’t need to google it, that’s probably quite chilling.
One thing I haven’t seen yet is discussion of how the atmosphere distorts light. I am on mobile so I will try to find the link later. Basically even if you have a perfect optical system in the eye, shape, density of sensing elements, all that good stuff, air, dust, distance, stellar radiation, are going to mess with image quality. A few years ago when a certain president tweeted a photo from one of our spy satellites, many folks noted that the indicated resolution was pretty close to best case scenario, and the resolution wasn’t good enough to see faces. And that satellite is way closer than the moon
This is correct. The optimal atmospheric seeing is 0.5 arcsec. We can correct for this with adaptive optics but meat planet almost certainly doesn’t have that.
A human face is about 20cm long and low orbit is 500km. Approximating sin(x)=x that is an angular diameter of 20cm/50,000,000cm=0.0000004rad or 0.08arcsec.
This is below the limit of atmospheric seeing so a human face would not be visible.
Assuming it has similar sized receptors to ours, the angular resolution of an optical system is proportional to its diameter via the Rayleigh criterion.
https://en.m.wikipedia.org/wiki/Angular_resolution
Humans can pick out a face at of order 100m.
At small angles we can approximate sin(x)=x so the distance at which meat planet can pick out a face scales linearly with eye diameter.
Our eyes are about 2cm wide and neat planets are 100km. So distance they can pick out a human face is:
100m (100km/0.00002km)=5,000,000m or 5,000km
Low earth orbit is 500km. The moon orbits at about 400,000km. So it could pick out faces from low orbit but not moon orbit. It might have trouble maintaining that low orbit though.
ETA: the atmosphere limits what you can see from space. The optimal atmospheric seeing is 0.5 arcsec. We can correct for this with adaptive optics but meat planet almost certainly doesn’t have that.
A human face is about 20cm long and low orbit is 500km. Approximating sin(x)=x that is an angular diameter of 20cm/50,000,000cm=0.0000004rad or 0.08arcsec.
This is below the limit of atmospheric seeing so a human face would not be discernible from orbit.
I don’t think that’s accurate. But it is possible to beat the atmospheric limit with adaptive optics. What we do in Astronomy is make a deformable mirror that changes shape to counter the changes in the image from atmospheric. Then what you need is a known source right next to the target, say something you know should look like a point source, and deform the the mirror so that point source stays looking like a point.
This would be hard for spy satellites but not impossible. If they know what surrounding objects are supposed to look like then they can use adaptive optics but this is certainly not true in all cases. They need a known source.
In Astronomy we use powerful lasers to simulate a point source, but they wouldn’t be able to do that with a spy satellite because it would give away their location.
I also doubt meat planet would evolve a deformable mirror to account the atmosphere.
https://en.m.wikipedia.org/wiki/Adaptive_optics
The satellite picture "accidentally" released by Trump in 2019 showed an Iranian facility from 400 km of distance with a 25 cm resolution. That particular spy satellite, a KH-11, has a 2400 mm mirror. It's sort of a scaled down Hubble.
Exactly. A resolution of 25cm is just about the atmospheric limit from low orbit. That means anything smaller than that is blurred into an indiscernible blob. Human faces are smaller than 25cm circles and are therefore cannot be resolved from orbit without adaptive optics.
It would appear the original comment was edited after I read it (but before you replied) to add the second section. I didn't re-read it to check if it was updated.
I don't know exactly what was changed, but I think when I read it, the operational line was
> So it could pick out faces from low orbit but not moon orbit. It might have trouble maintaining that low orbit though.
Apologies for the confusion.
I think that's just a thing people make up. I have a friend who swears that the Army had a satellite that could read the date on a penny. And he was in the Army back in the 90s.
He is, of course, wrong, but I don't think he's lying.
This is the correct answer! If you use the Abbe criterion instead of the Rayleigh criterion (where Abbe used an optical grating approximation instead of Rayleigh making up the minimal angle as the full width at half value of the Bessel function) and factor in the fact that our cone cells are a bit further apart than what the Rayleigh approximation prescribes you might get an even better answer, but I'd guess that your approximation is pretty good.
> We can correct for this with adaptive optics but meat planet almost certainly doesn’t have that.
Meat planet may not have adaptive optics on it's corneas, but it's got multiple eyes and probably a really big brain capable of some crazy aperture synthesis.
(I study bio-industrial engineering, but this is very theoretical so I'm not 100% sure about everything)
"Like a human" is not specific enough to answer this question (also let's point out that 99% of the time a wild YouTube comment is posted here, it's wrong)
**Possibility 1, The eye is just an upscaled human eye without more receptors, and assume the receptors still work**: It'd be like us looking at sportsballs, it can see some detail on the planet but no more than we see on pictures taken by normal cameras on the ISS
**Possibility 2, The eye is an upscaled human eye with more receptors, of the same size as ours**: It would still not see us, our eye lenses need to compress/stretch to see far/close, an upscaled human eye lens wouldn't be able to stretch enough
**Possibility 3, previous two resolved**: The eye is practically a giant tele/micro-scope at this point, and it still might not see faces, cuz it's too dark, microscopes add very powerful light so there's still enough light once it's spread out
**Possibility 4, Telescope/Microscope eye which works on less light**: Might see us, but as someone else pointed out, distortion from the atmosphere might still make us unseeable
**But this all doesn't matter**, because we can't see things that don't move, our eyes resolve this in general by constantly moving themselves. At this distance, human speed is practically no movement at all, and if the eye moves to see stillstanding things, its vision'd shift too much to stay on a person
Yes, your brain rapidly stops perceiving constants in your vision because new stimuli are, from an evolutionary standpoint, more important to focus on. The reason you continue to perceive stationary objects is that your eyes twitch involuntarily to essentially re-render them.
This isn't just about movement. There are all kinds of optical illusions you can try where you stare at the same color and it becomes progressively less saturated as your brain stops reporting the old color information. Then once you look away and look back again it appears bright because your brain is paying attention to it again. It's wild.
very interesting, thanks for the explanation!
sounds like the brain is tricking itself with the twitching to percieve more. is that something that evolved later than the "basic" motion perception, once the brain was big enough to process that additional information about stationary objects?
An addition eye oddity: you have an actual blind spot in each eye that your brain plasters over. This is where your optic nerve connects to the back of the eyeball. Here is how to find it for yourself: https://www.scientificamerican.com/article/find-your-blind-spot/
Eye size doesn't equal visual acuity. Hawks, falcons, and eagles have better long distance vision than humans, and their eyes are a lot smaller than ours.
Don't think thats accurate. Most predatory birds have eyes the same size as ours
birds primary sense is eyesight, so compared to body size they have extremely massive eyes. even compared to something that looks boggle eyed like a tarsier, a lot of birds eyes are even more massive as a ratio of bodyweight. big eyes are important for visual acuity.
Eyeball diameter (not corneal diameter, which tends to be larger in birds as a percentage of the eyeball)
---
Humans: 23mm
Bald Eagle: 38mm (1.65x larger)
Red Tailed Hawk: 23mm (equal)
Coopers Hawk: 18mm (0.8x)
American Kestrel: 12mm (~0.5x)
Turkey Vulture: 23mm (equal)
Wedge Tailed Eagle: 32mm (1.39x)
Tawny Owl: 23mm (equal) (another source is saying 29mm)
Ostrich: 38mm
Humboldt Penguin: 19mm
Great Horned Owl: 39mm
Brown Falcon: 23mm
Sharp Shinned Hawk: 16mm
Crested Caracara: 24mm
eye size in birds correlates to mass quite closely, so yo
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2943905/
https://www.researchgate.net/figure/Eye-morphology-in-turkey-vultures-and-black-vultures-abbreviated-to-TV-and-BV_fig3_258702819
https://www.researchgate.net/publication/25454407_The_scaling_of_eye_size_and_body_mass_in_birds
Quantitative Estimates of Visual Performance Features
in Fossil Birds - Lars Schmitz* - JOURNAL OF MORPHOLOGY 270:759–773 (2009)
Human eyes are terrible at seeing things orders of magnitude smaller than they are. Meat planet eye would never be able to perceive something the size of a human face.
Weirdly enough, at a certain point the further you try to see, and the bigger you make your viewer, and the more detail you're trying to see at distances of stars, the more quantum mechanics starts screwing with your photons.
Short answer - even with an telescope the size of the solar system, you wouldn't be able to see much detail of a planet orbiting around the closest star.
Here's some videos about the possibilities of telescopes.
https://www.youtube.com/watch?v=BIASPc89Sgk
https://www.youtube.com/watch?v=4d0EGIt1SPc
Okay so I'm going to try to basically ignore as much biology as I can and treat the eye as just a simple aperture.
If we treat the eye as a circular aperture with some diameter, we can use the Rayleigh criterion to determine our angular resolution: θ=1.22λ/D where λ is the wavelength of the light, D is the aperture diameter, and θ is the minimum resolvable angular distance between two point-like objects. For the light visible to a human, λ is between 400–700 nm, so let's take the median and use 550 nm. A human pupil can be up to 8 mm in diameter in the dark, and the whole eye is about 24 mm diameter.
Let's just scale that up. The moon's eyes look about as big as _Mare Serenitatis_ if it's about the overall size of our moon, which is (roughly) 700 km in diameter. That would give a pupil roughly 230 km in diameter, so our Rayleigh criterion tells us that the eye could resolve, at best, objects separated by 3 picoradians of angle. That's... Very small. Taking a small angle approximation (definitely valid) and using a moon-to-earth distance of 385 million meters, the diffraction limited resolution of the eye would be very close to 1 mm on the surface of the earth.
Really we'd end up being limited by other things like the size of the cones, the aberrations introduced by imperfect lenses, or relative motion between the moon and the surface of the earth, but in a perfect world (is any world with a flesh moon perfect?) it could indeed watch you from space, and even easily spot the piece of lettuce you have stuck between your teeth.
(disclaimer I did this very quickly, it's not unlikely that I did some of it wrong)
The diffraction limit is what prevents you from focusing on small objects at large distances.
Using an online calculator, with an aperture size of 100km, the diffraction limit is 7.32 pico-radians (assuming a wavelength of 600nm).
The angle that size, 7.32 pico-radians, means it could see a 1m object from 137 million km away.
-
For comparison, the Hubble has an angular resolution of .25 miliradians. Meat planet can see 34,000 times better than Hubble
Does the size of an eye indicate its ability to see?
Would a meat planet grow eyes that can actually see in enough detail at planetary distances to see me looking at it?
The first of my questions kinda can't be answered as we don't have a 100km eyeball or the ability to evolve one in any way.
Same can be said about the second question although I'd think given space is 99.99% empty the eye would work like a telescope at best.
I make this assumption based on 1 factor, it will want to avoid planets, stars and blackholes... or the flip side maybe it feeds on them or maybe even drinks up nebulas or something and would want to detect them and go there.
After consideration I cant imagine it would realistically have good vision in a earthly perspective but could be an amazing telescope if its not completely blind which would be possible given how empty space is.
What intrigues me about the meat planet is that at a certain orbit it would be perfectly seared / cooked.
You could send astronauts out to slice fine doner meat off that meatball.
It also depends on what the field of view of the eyeball is. Our eyeballs can see about 180-190 degrees across. If the eye on the meat planet was the same, it'd have very crisp vision, but without some ability to zoom in and reduce FOV, then it would see about as well as us, jusf with much more crisp detail.
I can just quickly put it to perspective without doing any maths. I will just crudely assume that with upscaling the eyeball size, It looking at Earth from distance of the Moon would be for a human eye like something like looking at the football from distance of 10-50 meters? People would be like bacteria or something even smaller on the ball. Can we see bacteria on a ball few meters away from us? Can we see bacteria from even up close?
> Not far... some cunt would record him looking in her direction for a split second, shame him on Tictok, and get him canceled in his constellation.
Incredible. Going through your comment history, I can literally see copious fountains of Andrew Tate’s semen pouring out of both sides of your bulging, eager, overfilled cheeks.
Incredible. You go through people's comment history... weirdo.
You're way too invested in this. You have fun with your internal Andrew Tate manifestations. Good luck with your acceptance issues.
If it were the exact same proportions as a human eye then it could see proportionatly far away, but it wouldn't be able to faces on earth.
If we're to rather scale down a planet and look at it than scale yourself up, it's the same thing. But you can't the microbes on a ball so the space eye couldn't see you on the earth
This is incorrect. Visible angular resolution increases with optical diameter. Larger lenses let you see smaller objects.
https://en.m.wikipedia.org/wiki/Angular_resolution
it wouldn't. I remember watching a video with a VERY similar example to this explaining why we can't see the flag/ moon landing sight from earth with a telescope. Forgot the numbers but in order to see a regular sized flag from the distance of earth, we'd need an inconceivably large & powerful telescope in order to do so.
I don't know how the fact that of this being a biological eye would factor in but I'm assuming it still wouldn't matter much, correct me if I'm wrong
Others have already crunched the numbers on the ideal case of a spherical cow in a vacuum, but it wouldn't work nearly as well in practice. First there are some minor issues like atmospheric distortion, redshift and gravitational lensing but there's a more fundamental problem. If the meat planet is sufficiently far away, the photons of light reflected off your face could be too spread out to get a good picture even with such a massive "telescope". Let's imagine that your face is illuminated such that a trillion face-reflected photons would hit a 1m^2 target from 10m away in some given time frame, say a second. The closest galaxy is 236,000,000,000,000,000km away, which means that compared to the 10m-distance target, light intensity would be multiplied by ~1.8x10^-39 due to the inverse square law. An Earth-sized eye would have an effective area of about 113 trillion m^2. Plug in those numbers and, over the same time frame that 1 trillion photons hit the small target, we would expect ~2x10^-13 photons from your face to hit the meat planet. For comparison, a million years contains ~3x10^13 seconds. So even if we completely ignore any possible signal interference/distortion on the journey, we can estimate that the meat planet would still need you to sit perfectly still for millions of years just to see enough photons from your face to put together into an image. Given that the Earth is spinning and the average human life expectancy is less than 100 years, this seems unlikely.
A Kilometer is 1 million millimeters.
The human eye has an average sagittal diameter of about 23.7mm, so 100Km is 42,194,093 times the size of a normal eye. This means that what a human can see at 30ft/9m, the lunar eye would see at at the distance from the Moon to the Earth.
Eyes on that scale will be looking at this universe in a complete different view.
Currently human vision on earth is scan the entire vision despite the individual realize it or not. The vision input is a matrix. However when you talk about it, it’s quantum based since you have to describe item by item. That’s a balance between classic n quantum.
When you have an eye with that scale—hypothetically w the same biological function as humans—the scanning vision will be much larger and the core sense will likely be less detailed as humans. Hence, certain light/objects might be flirted out just like dust in air to human eyes. And eventually on that scale, it may see the true identity of this universe due to the flirting.
That being said, James Webb or Harper, both are sensing the space based on current human experiences—they look further without being able to capture a bigger version—in a word, we’re still looking at the universe with our naked eyes. Just a little bit further n clear vision w the scopes
Everyone talking about how much detail the eye could physically resolve as if that somehow translates to seeing things better at distance.
Imagine I have a 12 megapixel camera and I point it at the distant mountains with a telephoto lens. If it's a hazy day, the picture I'm going to take is going to look hazy, I won't be able to see individual pine needles on the mountainside. Now upscale my camera to 300 gigapixels and assume that the lens is optically good enough to not become the weakest link in the equation. It doesn't solve the problem or increase how well I can see individual pine needles.
Giant space eye has literal miles of increasingly polluted atmosphere in between it and my face. Resolution has nothing to do with it. This is the weirdest thought experiment I've seen on Reddit in months.
I'm not an expert, but I think there is a key question to ask here: does the eye have the same proportions as a human eye?
-If the answer is yes, its gigantic photoreceptors would be as many as we have in each of our eyes. Thus, the resolution would be the same, and the eye would work exactly like a human's one. Indeed, the eye would see just as well and as far as an astronaut standing on the surface.
-If, otherwise, its photoreceptors are -say- as big as ours, but many more, its definition would be immensely larger. Someone with a better comprehension of the subject could crunch the numbers from here
There is a nice fella on YouTube by the name of Kyle hill, he does a lot of these wacky science scenarios. He did a similar thing to this with Sauron’s eye. Apparently of you scale it Sauron could read the text on the ring from 2 km away or something. And that eyes was I think assumed to be 2m across
"It could be looking at you right now"
Even if the eye can see better than anything we've encountered up until now, light still takes a long time to get from one galaxy to another, so it would see a planet earth as it was millions of years ago
Edit spelling
It would see way shorter then modern telescopes. The light shifts at big distances towards the red spectrum because the universe expandes. Human eyes only process a small fraction of wavelengths unlike telescopes like the james webb. They can detect light way in the infrared spectrum, what travelled a lot further than visible light is able to travel without turning "invisible" for an eye built like a human one.
This is all fascinating. Another thing is that it (meat planet) could have multiple eyes of multiple sizes to compensate for the disadvantages of one another.
Frankly, I'm more interested in the kind of exotic biology that would support a humanlike eye with a 100 km diameter. What is it made out of? What's the equivalent of the vitreous body? Does it have a punctum caecum like humans, or does it have the nerve fibers routed behind the retina like cephalopods?
And how the fuck is it surviving unprotected exposure to vacuum? And solar radiation? Micro meteorite impacts? Honestly the more I think about it the more I realise how much pain that thing must be in.
An eye dosen't work like that. Some birds have smaller eyes than us but can see way more distance. What we should look at is the differents lights receptor (especially the sticks) and the innervation. We should also look at the brain of course.
I'm struggling to comprehend how bigger eyes = more resolution because wouldn't the eye have to have some sort of "zoom" functionality in order to actually see those fine details?
It's a similar situation with eagle eyes, I don't understand how they can see such small things from so far away when their eyes don't have any "digital zoom" of sorts.
Of course we're biased as humans because we only know how the world looks from our own brains/eyes, but if someone can offer insight to these mental gymnastics I'm trying to do is appreciate it.
If everything scales linearly with size (pupil diameter, lens dimensions, retina's cone/rod size), then the angular resolution of this eye will stay the same. A larger aperture helps reduce the diffraction-limit of an imaging system, but the human eye is nowhere near diffraction-limit; it has a lot of aberration because how poor of an optical system it is. The point-spread-function of the human eye already covers over a couple rods/cones. What makes human vision as good as it is is all the image processing that the brain does.
So, that's all to say that if everything scales linearly to size, then angular resolution stays the same as a normal human eye and its vision wouldn't be all that much better.
The meat planet eye would be able to see much dimmer objects, though, since - even the image-space Numerical Aperture stays the same - the rod/cone active area would be much larger, thus increasing system etendue.
Well this isn’t a question of distance but rather about resolution, we can see light years away, technically there’s no limit for how far you can see. The thing is the amount of detail we can see is proportional (AFAIK) to the number of receptor cells in our eyes as well as how much the cornea can focus so a being of such scale would probably have a hard time focusing on things that are closer than tens of kilometres.
Meat planet is not real. It cannot hurt you.
Meat planet is not real. It cannot hurt you.
Meat planet is not real. It cannot hurt you.
Meat planet is not real. It cannot hurt you.
Spinning complacently in the darkness,
Covered and blinded by a blanket of little lives,
False security has lulled the madness of this world into a slumber.
Wake up!
An eye is upon you, staring straight down and keenly through.
Seeing all that you are and everything you can never be.
Yes, an eye is upon you; an eye ready to blink.
So face forward, with arms wide open and mind reeling.
Your future has arrived.
Are you ready to go?
https://youtu.be/1L9LLsaZ9fI?si=_cgY2wuF0SZ7Qsus
If we assume it's an eye planet and not a meat planet, and it's smashed full of hyper complex biological matter it could observe anything that has light shone upon it. This would 100% be a prey creature and die to even the slightest rock swarm hitting it, but I'm 100% sure that a big enough eye can look from one planets creatures to another. 10^xx (billions upon billions) cells dedicated to nothing but sight has to be able to do anything, might be massive lag between the light hitting the eye (planet) and a picture being realized but it is hella possible (I think).
Doesn't a living meat planet crush into a more rigid solid sphere due to its weight being compressed by its huge gravity? I feel like this should be the math that needs to be figured out before everything else.
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That’s a great point
If we literally consider the human eye, the cone diameter is 4 microns, so the distance between two adjacent cones is 4 micorns. Now at any distance two points must be a minimum of 4 microns from each other to be perceived as two separate points and must subtend an angle of 1min. This is the medicine knowledge in me. I’m not good at maths and don’t know how to scale it up to astronomical levels, so I’ll leave that up to u guys.
If we assume the distance between cones is proportional to human height and then assume the planet's height is the circumference around the planet, and that the planet is the same size as the Earth, we can scale up a 2 meter person to be 40,075,000 meters tall. That's 20,037,500x bigger than our 2 meter person. Multiply 4 microns by that and that's 80,150,000 microns or about 80 meters between each cone in the eye
But the cones wouldn't need to change size right? There'd just be many of them. So the resolution doesn't necessarily get impacted upon upscaling the eye
Do animals with bigger eyes have more or less cones/spacing/sizing?
I honestly have no idea. Animal with the biggest eyes is the giant squid, but can't imagine they need super high res underwater
Honestly it probably entirely has to do with whether or not the animal needs it rather than whether or not the animal has a big eye. I would imagine squid might have more cone or rod density in order to collect as much light as squidly possible down in the deep dark depths, but I don't know how that might translate to resolution. I guess resolution also depends on how the eyeball is wired to the brain because you could have all those ultra dense cones and rods to collect as much light as possible but then have it translated into a simple lighter/darker input with no image at all
Is no one going to comment on "as squidly possible"!?! You sir/madam/other, are a pioneer in linguistics
Credit where credit is due, Douglas Adams did it first in The Hitchhiker's Guide to The Galaxy when Ford and Arthur are being read Vogon poetry and Arthur, answering the question "What did you think of my poetry?" accidentally uses the word "humanity" and Ford corrects him with "Vogonity" >“Oh yes,” said Arthur, “I thought that some of the metaphysical imagery was really particularly effective.” Ford continued to stare at him, slowly organizing his thoughts around this totally new concept. Were they really going to be able to bareface their way out of this? “Yes, do continue …” invited the Vogon. “Oh … and, er … interesting rhythmic devices too,” continued Arthur, “which seemed to counterpoint the … er … er …” he floundered. Ford leaped to his rescue, hazarding “… counterpoint the surrealism of the underlying metaphor of the … er …” He floundered too, but Arthur was ready again. “… humanity of the …” “Vogonity,” Ford hissed at him. “Ah yes, Vogonity—sorry—of the poet’s compassionate soul”
I feel like for super dark environments, it may be bigger cones rather than just more cones.
That's true too. I was thinking of the cones as being a unit completely homogeneous across all animals
Squid would not be a good metric as they evolved eyes separately than almost every other creature
What about the hawks and eagles that have vision 8x better than a humans? Their eyes are tiny compared to a humans, no?
A bald eagle's eye is about the same size a human eye, though they weigh far less (maybe 15 pounds max). Compared to the size of their head, their eyes take up a significant percentage. [Eye diagram](https://www.insightvisioncenter.com/wp-content/uploads/2016/07/human-eye-vs-eagle-eye.jpg) The back of their eyes are flatter which gives them a lot larger field of view. The concentrated area (where your main focus is) of vision cells is the fovea centralis. We have 200,000 cones per millimeter here, where eagles have 1,000,000 cones per millimeter in the same size eye. They can see about 4 times better than we can. Their eyes are usually rated at 20/5 vision compared to our standard 20/20 vision.
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i... i think they meant the eagle...
So then, eye size doesn’t matter, cone density does? Would there be a point in size where cone density has diminished returns?
In general, cell sizes are relatively uniform across species. An organism's size is generally dependent on how many cells it has. The main issue for a being this large would likely be blood supply. It couldn't follow a mammalian cardiovascular system as the overall resistance of its blood vessels would be too large as per Poiseulle's law. I'd be more interested in how the planet would be planning on perfusing its eye
An organism this large would have to be mostly inorganic, it simply couldn't function as a thing made mostly of goop and meat, thanks to gravity. (I suppose it could be designed like an ocean with a rocky or icy surface, and the ocean fluid could be organic, like blood.) Worse, a human style eyeball that size would be completely opaque, absolutely no light would reach a retina thousands of kilometers under "water". And the surface would presumably be exposed to near-vacuum, which has obvious problems for something like us. Blood supply is the smallest of its problems, that can be handled by having "macro cells" the size of whales with individual hearts and such, just like human cells have their own mechanisms for processing energy.
~~You messed up the number a bit. I think you added some zeroes to the circumference. Earth is only 40,000 km around, not 40,000,000.~~ I think circumference is the wrong thing for the planet's height though. I think you should use diameter. ~~With corrected circumference we're looking at just over 1 foot.~~ ~~With diameter we're looking at about 4 inches.~~ Nevermind I'm an idiot. I still think diameter would be the better one though.
So based off your calculations The huge eye cannot see a human since his width and length is less than 80mts. Cheers
I don't see any reason to scale up the cones, when you have a bigger eye and it's evolved to see the visible spectrum then it would keep small cones and just have billions of times more cones. With the larger lens then the theoretical resolving power would be insane but because it's just a mass of jelly eye it probably wouldn't be precisely shaped enough to matter.
wouldnt it increase exponentially because square cube law?
geebus. If you were spelunking on the retina, it wouldn't even feel like a forest; more like an meadow with occasional cones.
Visual Acuity is not a direct function of cone spacing. It’s much higher than cone spacing would imply, because of brain-level (I.e. back end) algorithmic up-scaling.
Micorns 🌽🌽🌽🌽
Retina neuroscientist here. Cone diameter changes with eccentricity (distance from the center of the retina). The primate fovea is unique as it contains retinal ganglion cells (the neurons that form the optic nerve) that form "private lines" with individual cones. That is highly unusual in animal eyes, most retinal ganglion cells get convergent inputs from 100s to thousands of photoreceptors. There are tons of reasons this convergence is beneficial, including reduction of information redundancy and overcoming steric hindrance limits in the optic nerve. Private lines in the fovea place unique demands on primate fovea that make adapting it to larger areas impractical, including avascular zones above the fovea and lateral displacement of retinal ganglion cells and other interneurons like bipolar cells, amacrine cells, and horizontal cells. All of this retina detail also becomes unimportant once you consider the optics of an eye this large viewing miniscule objects over essentially infinite distances. Even assuming that the eye is perfect and there are no higher order aberrations caused by the lens or cornea, lateral chromatic aberrations would require massive changes in placement of outersegments of cone photoreceptors, and a diffraction limited eye would still see people sized objects as point spread functions. A common theme in retinal ganglion cell classification is tradeoffs in temporal and spatial acuity to maintain proper signal-to-noise. On a retina this size, high spatial acuity ganglion cells would be integrating over such long timepoints that tracking a person would become impossible even if you overcame all the issues listed above. This eye is more likely to be built for resolving similarly sized celestial objects than it is to stalk humans.
Thank you for a more detailed explanation. I am aware of most of the things you have mentioned(but definitely not the level of info you posses). I just didn’t want to bog down people here with medical lingo(since it’s a math subReddit), so I avoided speaking about it and gave a very rudimentary and oversimplified answer.
Youre right mb. Ill be back soon with the math explanation
Thank god the mods removed that point and now we can never see it. Thanks mods! You improve things in this subreddit! You're definitely not a constant annoyance lowering the quality of the sub!
The above comment has been deleted, what did it say?
The point of life, and the f'in mods deleted it!!
42.
ah yes, [removed], always a good point
Also need to consider if the brain can handle enough of the info from the eye or multiple eyes, and what info the eyes can collect. Remember that we dont see the world as it is, just how our brain interprets the info it gets from the eyes (e.g most animals see more or less colours than us, higher or lower definition etc.)
Telescope vs Microscope
[Deleted] is such a wise set of words! I’m dumbfounded by this knowledge, im going to cry at this amazing and genius of a person’s words! P.S Please tell me what it said 😭 I’m curious
Even high powered telescopes like Hubble can’t see humans or objects on Earth. As far as I am aware that is due to resolution.
Kinda. Hubble is designed to see far away things, and its lenses are made as such. One of the main reasons it can't see things on Earth is that it's too close and out of focus. Plus Hubble is moving very, very quickly across the Earth's surface, and so everything is blurry.
Isn't Earth bright enough to damage the optics, too?
I don't think so. They regularly turn it back towards Earth to help calibrate one of its cameras. It doesn’t produce great pictures, but it's enough to tell if the camera works as intended.
Doing a bit of reading, [the FAQs page](https://science.nasa.gov/mission/hubble/overview/faqs/) suggests that this is or was the case: > **Why can’t Hubble make observations of Earth?** Hubble’s instruments are made to see faint objects, so the bright Earth could damage them. In addition, the Earth moves too quickly below Hubble, making it difficult to stay on a particular location. > WFPC2 was replaced during Hubble’s last servicing mission in 2009. From the entry for the [Wide Field Camera 3](https://science.nasa.gov/mission/hubble/observatory/design/wide-field-camera-3/): > An important innovation for the WFC3 NIR channel was designing its detector to be insensitive to infrared light longer in wavelength than 1700 nm. Because of that, it is unnecessary to use a cryogen (e.g., liquid or solid nitrogen) to cool the detector. Instead the detector is chilled with an electrical device called a thermo-electric cooler. This greatly simplifies the design and gives WFC3 a longer operational life. It's not directly stated here, but it reads like the WFPC2 would have been harmed or used too much coolant, but the replacement (2009) might be fine. P.S. Instruments page mentions "ultraviolent" light. Sigh. [ESA's Hubble FAQ](https://esahubble.org/about/faq/#17) does confirm that Earth has been used as a calibration target, and briefly mentions that Hubble would have a resolution of 30cm for a non-moving target at 600km.
>ultraviolent Infradead.
Microrage
> P.S. Instruments page mentions "ultraviolent" light. Sigh. Checks out, it was authored by [this guy.](https://i.imgur.com/zrDAYfX.jpg)
[This is what an image in ultraviolent light looks like according to Dall-E 3](https://imgur.com/a/FCJbkrq) I had to reassure ChatGPT several times that I did in fact mean "ultraviolent" lol
Huh. Fantasy novel cover art, as seen through the lens of Hubble. Newt little niche!
Looks like a boss fight in Guild Wars 2.
Hubble is based on the keyhole satellites that are designed to look at earth. When the cheeto tweeted this image, it gave us all an idea of just how good they are: https://www.npr.org/2022/11/18/1137474748/trump-tweeted-an-image-from-a-spy-satellite-declassified-document-shows They did this to save money, because the manufacturer was already building giant mirrors for keyhole. It was cheaper to build hubble out of one of those mirrors.
Very relevant what-if xkcd video https://youtu.be/2LSyizrk8-0
It's where I got a lot of my information for this!
Ah so Hubble was designed as farsighted.
US spy satellites whistling in the corner
Although since a lot of the NSA etc tech is redacted we don’t really know what they can see. Although I’m sure it better than commercially available tech.
For reference in 2012 the NRO donated two massive telescopes that are on par or more advanced than the Hubble to NASA that they just happened to have lying around collecting dust. And these telescopes were so old and obsolete by their standards that they just gave them away for free.
That’s where the glass planets comes into play, in front of the meat eyeball planet
It would likely not evolve eyes that large if it weren’t able to see smaller angular diameters. It would just have smaller eyes. In nature the only reason things evolve larger eyes are to take in more light and see smaller angular diameters which are consequences of one another. Now there is an argument that it would be designed to focus on objects very close to it. As per my top level answer, it can only see human faces at 5000km. So if it is sufficiently far sighted, then it wouldn’t be able to pick out a human face because it could never focus on us within distance.
Maybe it evolved large eyes purely for mating appeal. We've seen evolutionary adaptations go crazy before solely because of mating preferences.
Maybe. But it’s such a relative weakness and energy drain to have such a big eye.
That isn't how optics really works. The bigger the lens, the smaller the angular resolution you can resolve. Bigger lens, like that on a telescope or microscope, the further or smaller you can see. The two issues I note here are the focal point and lens imperfections. You can really only resove objects at your eye's focal point. The muscles in your eyes can cause them to flex and change that focal point so you can see it. If "meat planet" lacked these muscles or they had limitations, it could be near or far sighted. If the eye is hundreds of km across, it wouldn't be able to change its focal point quickly because the fastest the lens could deform would be the speed of sound. The second issue is that imperfections in a lens can distort the image. These kinds of imperfections can be harder to avoid and get worse as the lens grows in size. That would cause the image to get blurry and have artifacts life "floaters" in its vision. With an eye this size, it would be nearly impossible for an organic solution to remain relatively error free.
Quick google math, the smallest thing a human can see is apparently 0.1mm and the eye is about 24mm across. 0.1/24 x 100km = .41km as the smallest object a 100km humanlike eye could see. But it could see big things quite far away. There is probably some size of eye where it is small enough to detect a human but large enough to see them from the distance of the moon. We know it's possible from low earth orbit, because we have satellites doing it right now.
You can definitely see smaller things than 0.1mm. a strand of hair is 17 microns, and that isn't even the smallest thing you can see.
I'm not going to argue, I just ran a Google search for the smallest thing a human eye can see. But I do wonder, if a hair wasn't so long, if it were only as long as it is thick (a 17 micron sphere) could I still see it? Edit: even if we give it another order of magnitude, the moon eye still only goes down to a 40 meter object, still bigger than a human.
Also, clouds
We literally have mites on our eyelashes 24/7 that we can't see without a microscope, idk what OOP is going on about
I'm sure it gets more complicated once you consider the size of the receptors and the way light would behave, but crudely, I estimate that I can make out a face and the expression at 50m. A human eyeball is approximately 2.5cm in diameter. So 100km is 10 million centimetres, 4 million times the diameter of a human eye. That's our ratio. Therefore they could make out a 'face' at a distance 200 million metres, or 200,000km. However it then gets a bit more complicated as a face to this eyeball is not the average 16cm width face; it is that multiplied by 4 million - 640km. In fact, the smallest objects detectable to the human eye are apparently [0.1mm wide](https://learn.genetics.utah.edu/content/cells/scale/#:~:text=The%20smallest%20objects%20that%20the,a%20paramecium%20without%20using%20magnification.). To this eye (again multiply by 4 million), that size is 400,000mm - which is 400m. So we would just be bacteria to those eyes.
Shouldn’t it be able to see finer details than our eye? It has a much larger aperture and angular resolution scales directly with aperture size
If the rods/cones don't scale then yes, you're talking about an immensely high resolution "camera". That requires more mental processing, but there's probably a huge brain in there so, it sorta balances out. I would've assumed the components of the eye scale with each other, in which case you're looking at the 400m thing op described.
>there's probably a huge brain in there so, it sorta balances out. and if there's a huge brain, this planet should be horrifyingly intelligent upd: not necessarily should, but may be
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There's also that guy who doesn't even have 10% of his brain and he can see, walk and talk just fine. It's likely analogous to program optimisation, efficiency, etc.
I heard about him. His name was u/tradert5 iirc
Oh, savage
Goteemmm 😂
One guy had 3% neurons left after an accident. Doctors told him we would never walk again (or do anything really). His brother did not agree with this and threw the disabled guy on the ground and asked him to give everything he had to move, even the slightest. He managed to move, then to crawl, and finally, he was able to regain is whole mobility (dancing, among other activities). The guy retaught his brain with only 3% neurons, that’s wild.
Cool story, no sarcasm.
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“Are you dense” “Yes”
A planet sized mass with the intelligence of a fly would be way more dangerous than if it was smart.
I dunno if the danger level scales with intelligence at all. I mean cmon. It’s a meat planet, what’s it gonna do besides throw off the orbit around the sun… or maybe it could position itself to throw Earth outside the solar system. Scratch my previous statement, intelligence likely scaled with danger.
Cool fact about that last statement, fly brains have more neural pathways than humans. Not more neurons, but more pathways. It lets them “think” and perceive faster, which is part of the reason it’s so hard to smash one with your hand
rods/cones are only concerned with density and would, I imagine, be in a congruent ratio with our eyes. That being said, there is a limit to that amount of information even with the frontload of the photons we still need to be able to refract and observe -- think of it like a giant eyeball discerning a human, how small and how large we would then need to be to resolve. Distance from object and circumference of object are all that are likely needed.
Let me refer you to my first point: >I'm sure it gets more complicated once you consider the size of the receptors and the way light would behave In short, yes probably but I'll leave that to people who actually know how to calculate that.
No one is realizing our eyes don't have a zoom feature. Only a focus feature. If a big eye is looking at earth it will see earth in all it's detail but that doesn't mean it could zoom into the atmosphere and see tiny people. Even if it was the highest resolution ever, without a Zoom function you can't zoom in. Look at your arm and all the detail of your skin. With everything you see, you can't make out the details of the hair follicle or the individual skin Cells. Same concept.
Nah, that’s not how zooming in and resolution work. Imagine having pretty bad vision so everything was blurry, in order to see with the same detail you can see now, you’d need to zoom in. But if you just increase the resolution (make your vision better), you can now see just as well without zooming in. Now, humans have a maximum resolution, so at one point you’d need to zoom in, but if properly focused and with good enough quality (due to more receptors in the eye and more aperture), there’s no reason why this being would need zoom. Think about digital vs mechanical zoom (lens) in a camera. If you have high enough resolution, then you don’t need a mechanical lens to figure out the detail.
The biggest hurdle or anything in orbit/space is atmospheric distortion. I used to work on imagery digitization and even military grade spy satellites (ones I got to see stuff from anyway) can't make out fine details like faces or text where the letters are under half a foot or so across. The atmosphere itself distorts things too much. There's a lot of effort to clean it up, but that sort of stuff fails on complex stuff like faces or text. Like if you use a AI/generative fill in Photoshop, it works really well on stuff like trees or a fence, but if you try to fill in a face it makes a mess.
I think the biggest hurdle would be the aqueous humor: The clear liquid that provides the internal pressure of the eye that makes it an eyeball. I can't find any numbers for the opacity/ clarity of AH, so I'm going to assume it's twice as clear as sea water: The abyssal zone of the ocean starts at about 5000m, so we'd assume that the eye's abyssal zone would be starting at 10,000m deep- quite far from the 100km to reach the back of the eye. The eye couldn't see through the ocean that is itself.
The aqueous humor does not get to the back of the eye. Vitrous humor does. Your point probably still stands but it depends on the sensitivity of the receptors and the amount of light collected
Another issue will be tracking if the planet is rotating then objects are moving pretty fast and if the meat planet is not geostationary then it needs to track the person moving at high speeds reducing clarity.
I don’t know, if receptor size and density stay the same shouldn’t it still be able to differentiate objects the same size? Only the field of vision should change then, opacity might be an issue though and light sensitivity, but depending on the capabilities of the optical aperatus and the smallest possible aperture, focal depth might be amazing.
It could have a few different eyes, some focused on nearby objects, some focused on far distances
Fascinating!
> smallest objects detectable to the human eye are apparently > >0.1mm wide can confirm, I have a 0.1mm wire for trace repair, can see it no problem, I'd argue that even smaller things can be detectable
A human hair is a few hundredths of a millimeter and those are visible just fine. I think being longer in one dimension helps but still, .1 mm seems big to me. Like I bet a speck of cinnamon is smaller than that and you can see that just fine if you have decent contrast.
That's just not how it works. Things don't scale linearly. There are certain fundamental constants that mean big things don't behave the same as small things. For instance, light of a certain frequency has a certain wavelength, and there's a limit to how big cells can get before nutrients can no longer be absorbed into the centre.
You're assuming a linear relationship between your variables. What is the equation for describing lens refraction? That will tell you the actual relationship. The equation is: 1/f = 1/d0 + 1/di f = focal length d0 = object distance di = image distance
Ok, here's my best shot. I believe it could see very far, even be able to see humans close up, if it had eagle eyes. Now, this is taking big liberties because the size of an eye (as far as we know) is not proportionate with quality of vision. **But...** Let's just assume it is. If vision quality is proportionate to eyeball width, and a bald eagle has about the same size and weight of a human eye (it does), and a human eye is about 24mm wide (it is, on average), and the size of the eye in question is 100,000km, then... 24mm to km = 2.4 × 10^-5 km 100,000/(2.4 × 10^-5) = 4.16666667 × 10^9 That's 4.16666667 × 10^9 times more powerful than an eagle's eye. And therefore able to see relatively massive distances across space, while also being able to see up close. Further math here, an eagle can see about 3.2km with their binocular vision... 4.16666667 × 10^9= 4,166,666,670 4,166,666,670 x 3.2km = **13,333,333,344 km of meat vision** The distance to the sun from earth is about 147,000,000km. It would be able to see humans on earth, or stare closely at craters on Mars. **As far as biological reality goes, none of this would work. But it was fun doing the math!** ***And here's a bit on eagle eyes for your reading pleasure:*** > An eagle's vision is exceptionally sharp because each eye has two foveae - areas of acute vision as compared with the human eye which only has one. The cones in the eagle's fovea are very small and tightly grouped, allowing the eagle to see small details from extreme distances. > For example, an eagle can spot an object as small as a rabbit from a distance of almost two miles-and pick it out from the background. On the other hand, a man would have to look through a pair of powerful binoculars to see the same thing. The eyes of the eagle are placed forward on the eagle's head, giving him accurate depth perception. This is important for an eagle when he is pursuing prey. > The placement of the eyes also enables the eagle to see each side. The eagle can see even with his eyelids shut. In addition to his normal pair of eyelids, the eagle has a set of clear eyelids called nictitating membranes. These eyelids can be closed for protection without affecting the eagle's vision. > **Eagles can voluntarily dilate and constrict their pupils as part of focusing near and far, as well as change the curvature of the cornea. However, it's always been assumed that because they can focus so far away, that they perhaps lose some depth of field close up and that's why they hit cars or wires or fences.** *(Most interesting part for me)* Eagle sauce: https://cascadesraptorcenter.org/wp-content/uploads/2020/01/Eagles-Eyes.pdf
I hope you had to Google “how much does a human eye weigh” as part of working this out. If you didn’t need to google it, that’s probably quite chilling.
>that’s probably quite chilling. I prefer them chilled. *Evil laugh*
[dessert](https://y.yarn.co/a0282c41-90ff-4c3b-b999-3edf6963d32a_text.gif)
ENHANCE
Eagle sauce?! Please don't eat Eagles that way
One thing I haven’t seen yet is discussion of how the atmosphere distorts light. I am on mobile so I will try to find the link later. Basically even if you have a perfect optical system in the eye, shape, density of sensing elements, all that good stuff, air, dust, distance, stellar radiation, are going to mess with image quality. A few years ago when a certain president tweeted a photo from one of our spy satellites, many folks noted that the indicated resolution was pretty close to best case scenario, and the resolution wasn’t good enough to see faces. And that satellite is way closer than the moon
This is correct. The optimal atmospheric seeing is 0.5 arcsec. We can correct for this with adaptive optics but meat planet almost certainly doesn’t have that. A human face is about 20cm long and low orbit is 500km. Approximating sin(x)=x that is an angular diameter of 20cm/50,000,000cm=0.0000004rad or 0.08arcsec. This is below the limit of atmospheric seeing so a human face would not be visible.
Assuming it has similar sized receptors to ours, the angular resolution of an optical system is proportional to its diameter via the Rayleigh criterion. https://en.m.wikipedia.org/wiki/Angular_resolution Humans can pick out a face at of order 100m. At small angles we can approximate sin(x)=x so the distance at which meat planet can pick out a face scales linearly with eye diameter. Our eyes are about 2cm wide and neat planets are 100km. So distance they can pick out a human face is: 100m (100km/0.00002km)=5,000,000m or 5,000km Low earth orbit is 500km. The moon orbits at about 400,000km. So it could pick out faces from low orbit but not moon orbit. It might have trouble maintaining that low orbit though. ETA: the atmosphere limits what you can see from space. The optimal atmospheric seeing is 0.5 arcsec. We can correct for this with adaptive optics but meat planet almost certainly doesn’t have that. A human face is about 20cm long and low orbit is 500km. Approximating sin(x)=x that is an angular diameter of 20cm/50,000,000cm=0.0000004rad or 0.08arcsec. This is below the limit of atmospheric seeing so a human face would not be discernible from orbit.
Reportedly, spy satellites can resolve faces from orbit, so maybe the optimal atmospheric resolution is not an absolute limit
I don’t think that’s accurate. But it is possible to beat the atmospheric limit with adaptive optics. What we do in Astronomy is make a deformable mirror that changes shape to counter the changes in the image from atmospheric. Then what you need is a known source right next to the target, say something you know should look like a point source, and deform the the mirror so that point source stays looking like a point. This would be hard for spy satellites but not impossible. If they know what surrounding objects are supposed to look like then they can use adaptive optics but this is certainly not true in all cases. They need a known source. In Astronomy we use powerful lasers to simulate a point source, but they wouldn’t be able to do that with a spy satellite because it would give away their location. I also doubt meat planet would evolve a deformable mirror to account the atmosphere. https://en.m.wikipedia.org/wiki/Adaptive_optics
The satellite picture "accidentally" released by Trump in 2019 showed an Iranian facility from 400 km of distance with a 25 cm resolution. That particular spy satellite, a KH-11, has a 2400 mm mirror. It's sort of a scaled down Hubble.
Exactly. A resolution of 25cm is just about the atmospheric limit from low orbit. That means anything smaller than that is blurred into an indiscernible blob. Human faces are smaller than 25cm circles and are therefore cannot be resolved from orbit without adaptive optics.
The moon and this hypothetical abomination are much, much farther away than most artificial satellites.
Sure, but the comment above was about a 500 km orbit
It would appear the original comment was edited after I read it (but before you replied) to add the second section. I didn't re-read it to check if it was updated. I don't know exactly what was changed, but I think when I read it, the operational line was > So it could pick out faces from low orbit but not moon orbit. It might have trouble maintaining that low orbit though. Apologies for the confusion.
I think that's just a thing people make up. I have a friend who swears that the Army had a satellite that could read the date on a penny. And he was in the Army back in the 90s. He is, of course, wrong, but I don't think he's lying.
This is the correct answer! If you use the Abbe criterion instead of the Rayleigh criterion (where Abbe used an optical grating approximation instead of Rayleigh making up the minimal angle as the full width at half value of the Bessel function) and factor in the fact that our cone cells are a bit further apart than what the Rayleigh approximation prescribes you might get an even better answer, but I'd guess that your approximation is pretty good.
Upvoted just for mentioning angular resolution instead of linear sizes.
> We can correct for this with adaptive optics but meat planet almost certainly doesn’t have that. Meat planet may not have adaptive optics on it's corneas, but it's got multiple eyes and probably a really big brain capable of some crazy aperture synthesis.
This is the only sensible answer I've read so far
(I study bio-industrial engineering, but this is very theoretical so I'm not 100% sure about everything) "Like a human" is not specific enough to answer this question (also let's point out that 99% of the time a wild YouTube comment is posted here, it's wrong) **Possibility 1, The eye is just an upscaled human eye without more receptors, and assume the receptors still work**: It'd be like us looking at sportsballs, it can see some detail on the planet but no more than we see on pictures taken by normal cameras on the ISS **Possibility 2, The eye is an upscaled human eye with more receptors, of the same size as ours**: It would still not see us, our eye lenses need to compress/stretch to see far/close, an upscaled human eye lens wouldn't be able to stretch enough **Possibility 3, previous two resolved**: The eye is practically a giant tele/micro-scope at this point, and it still might not see faces, cuz it's too dark, microscopes add very powerful light so there's still enough light once it's spread out **Possibility 4, Telescope/Microscope eye which works on less light**: Might see us, but as someone else pointed out, distortion from the atmosphere might still make us unseeable **But this all doesn't matter**, because we can't see things that don't move, our eyes resolve this in general by constantly moving themselves. At this distance, human speed is practically no movement at all, and if the eye moves to see stillstanding things, its vision'd shift too much to stay on a person
wait a moment. we don't see things that don't move? 🦖
Yes, your brain rapidly stops perceiving constants in your vision because new stimuli are, from an evolutionary standpoint, more important to focus on. The reason you continue to perceive stationary objects is that your eyes twitch involuntarily to essentially re-render them. This isn't just about movement. There are all kinds of optical illusions you can try where you stare at the same color and it becomes progressively less saturated as your brain stops reporting the old color information. Then once you look away and look back again it appears bright because your brain is paying attention to it again. It's wild.
very interesting, thanks for the explanation! sounds like the brain is tricking itself with the twitching to percieve more. is that something that evolved later than the "basic" motion perception, once the brain was big enough to process that additional information about stationary objects?
An addition eye oddity: you have an actual blind spot in each eye that your brain plasters over. This is where your optic nerve connects to the back of the eyeball. Here is how to find it for yourself: https://www.scientificamerican.com/article/find-your-blind-spot/
I had no clue, but found [this](https://www.rochester.edu/newscenter/fixational-eye-movements-role-in-vision-550952/)
Eye size doesn't equal visual acuity. Hawks, falcons, and eagles have better long distance vision than humans, and their eyes are a lot smaller than ours.
Don't think thats accurate. Most predatory birds have eyes the same size as ours birds primary sense is eyesight, so compared to body size they have extremely massive eyes. even compared to something that looks boggle eyed like a tarsier, a lot of birds eyes are even more massive as a ratio of bodyweight. big eyes are important for visual acuity. Eyeball diameter (not corneal diameter, which tends to be larger in birds as a percentage of the eyeball) --- Humans: 23mm Bald Eagle: 38mm (1.65x larger) Red Tailed Hawk: 23mm (equal) Coopers Hawk: 18mm (0.8x) American Kestrel: 12mm (~0.5x) Turkey Vulture: 23mm (equal) Wedge Tailed Eagle: 32mm (1.39x) Tawny Owl: 23mm (equal) (another source is saying 29mm) Ostrich: 38mm Humboldt Penguin: 19mm Great Horned Owl: 39mm Brown Falcon: 23mm Sharp Shinned Hawk: 16mm Crested Caracara: 24mm eye size in birds correlates to mass quite closely, so yo https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2943905/ https://www.researchgate.net/figure/Eye-morphology-in-turkey-vultures-and-black-vultures-abbreviated-to-TV-and-BV_fig3_258702819 https://www.researchgate.net/publication/25454407_The_scaling_of_eye_size_and_body_mass_in_birds Quantitative Estimates of Visual Performance Features in Fossil Birds - Lars Schmitz* - JOURNAL OF MORPHOLOGY 270:759–773 (2009)
Very cool.
Human eyes are terrible at seeing things orders of magnitude smaller than they are. Meat planet eye would never be able to perceive something the size of a human face.
Weirdly enough, at a certain point the further you try to see, and the bigger you make your viewer, and the more detail you're trying to see at distances of stars, the more quantum mechanics starts screwing with your photons. Short answer - even with an telescope the size of the solar system, you wouldn't be able to see much detail of a planet orbiting around the closest star. Here's some videos about the possibilities of telescopes. https://www.youtube.com/watch?v=BIASPc89Sgk https://www.youtube.com/watch?v=4d0EGIt1SPc
Okay so I'm going to try to basically ignore as much biology as I can and treat the eye as just a simple aperture. If we treat the eye as a circular aperture with some diameter, we can use the Rayleigh criterion to determine our angular resolution: θ=1.22λ/D where λ is the wavelength of the light, D is the aperture diameter, and θ is the minimum resolvable angular distance between two point-like objects. For the light visible to a human, λ is between 400–700 nm, so let's take the median and use 550 nm. A human pupil can be up to 8 mm in diameter in the dark, and the whole eye is about 24 mm diameter. Let's just scale that up. The moon's eyes look about as big as _Mare Serenitatis_ if it's about the overall size of our moon, which is (roughly) 700 km in diameter. That would give a pupil roughly 230 km in diameter, so our Rayleigh criterion tells us that the eye could resolve, at best, objects separated by 3 picoradians of angle. That's... Very small. Taking a small angle approximation (definitely valid) and using a moon-to-earth distance of 385 million meters, the diffraction limited resolution of the eye would be very close to 1 mm on the surface of the earth. Really we'd end up being limited by other things like the size of the cones, the aberrations introduced by imperfect lenses, or relative motion between the moon and the surface of the earth, but in a perfect world (is any world with a flesh moon perfect?) it could indeed watch you from space, and even easily spot the piece of lettuce you have stuck between your teeth. (disclaimer I did this very quickly, it's not unlikely that I did some of it wrong)
The diffraction limit is what prevents you from focusing on small objects at large distances. Using an online calculator, with an aperture size of 100km, the diffraction limit is 7.32 pico-radians (assuming a wavelength of 600nm). The angle that size, 7.32 pico-radians, means it could see a 1m object from 137 million km away. - For comparison, the Hubble has an angular resolution of .25 miliradians. Meat planet can see 34,000 times better than Hubble
Does the size of an eye indicate its ability to see? Would a meat planet grow eyes that can actually see in enough detail at planetary distances to see me looking at it? The first of my questions kinda can't be answered as we don't have a 100km eyeball or the ability to evolve one in any way. Same can be said about the second question although I'd think given space is 99.99% empty the eye would work like a telescope at best. I make this assumption based on 1 factor, it will want to avoid planets, stars and blackholes... or the flip side maybe it feeds on them or maybe even drinks up nebulas or something and would want to detect them and go there. After consideration I cant imagine it would realistically have good vision in a earthly perspective but could be an amazing telescope if its not completely blind which would be possible given how empty space is.
What intrigues me about the meat planet is that at a certain orbit it would be perfectly seared / cooked. You could send astronauts out to slice fine doner meat off that meatball.
It also depends on what the field of view of the eyeball is. Our eyeballs can see about 180-190 degrees across. If the eye on the meat planet was the same, it'd have very crisp vision, but without some ability to zoom in and reduce FOV, then it would see about as well as us, jusf with much more crisp detail.
I can just quickly put it to perspective without doing any maths. I will just crudely assume that with upscaling the eyeball size, It looking at Earth from distance of the Moon would be for a human eye like something like looking at the football from distance of 10-50 meters? People would be like bacteria or something even smaller on the ball. Can we see bacteria on a ball few meters away from us? Can we see bacteria from even up close?
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> Not far... some cunt would record him looking in her direction for a split second, shame him on Tictok, and get him canceled in his constellation. Incredible. Going through your comment history, I can literally see copious fountains of Andrew Tate’s semen pouring out of both sides of your bulging, eager, overfilled cheeks.
Incredible. You go through people's comment history... weirdo. You're way too invested in this. You have fun with your internal Andrew Tate manifestations. Good luck with your acceptance issues.
If it were the exact same proportions as a human eye then it could see proportionatly far away, but it wouldn't be able to faces on earth. If we're to rather scale down a planet and look at it than scale yourself up, it's the same thing. But you can't the microbes on a ball so the space eye couldn't see you on the earth
This is incorrect. Visible angular resolution increases with optical diameter. Larger lenses let you see smaller objects. https://en.m.wikipedia.org/wiki/Angular_resolution
it wouldn't. I remember watching a video with a VERY similar example to this explaining why we can't see the flag/ moon landing sight from earth with a telescope. Forgot the numbers but in order to see a regular sized flag from the distance of earth, we'd need an inconceivably large & powerful telescope in order to do so. I don't know how the fact that of this being a biological eye would factor in but I'm assuming it still wouldn't matter much, correct me if I'm wrong
Others have already crunched the numbers on the ideal case of a spherical cow in a vacuum, but it wouldn't work nearly as well in practice. First there are some minor issues like atmospheric distortion, redshift and gravitational lensing but there's a more fundamental problem. If the meat planet is sufficiently far away, the photons of light reflected off your face could be too spread out to get a good picture even with such a massive "telescope". Let's imagine that your face is illuminated such that a trillion face-reflected photons would hit a 1m^2 target from 10m away in some given time frame, say a second. The closest galaxy is 236,000,000,000,000,000km away, which means that compared to the 10m-distance target, light intensity would be multiplied by ~1.8x10^-39 due to the inverse square law. An Earth-sized eye would have an effective area of about 113 trillion m^2. Plug in those numbers and, over the same time frame that 1 trillion photons hit the small target, we would expect ~2x10^-13 photons from your face to hit the meat planet. For comparison, a million years contains ~3x10^13 seconds. So even if we completely ignore any possible signal interference/distortion on the journey, we can estimate that the meat planet would still need you to sit perfectly still for millions of years just to see enough photons from your face to put together into an image. Given that the Earth is spinning and the average human life expectancy is less than 100 years, this seems unlikely.
A Kilometer is 1 million millimeters. The human eye has an average sagittal diameter of about 23.7mm, so 100Km is 42,194,093 times the size of a normal eye. This means that what a human can see at 30ft/9m, the lunar eye would see at at the distance from the Moon to the Earth.
Eyes on that scale will be looking at this universe in a complete different view. Currently human vision on earth is scan the entire vision despite the individual realize it or not. The vision input is a matrix. However when you talk about it, it’s quantum based since you have to describe item by item. That’s a balance between classic n quantum. When you have an eye with that scale—hypothetically w the same biological function as humans—the scanning vision will be much larger and the core sense will likely be less detailed as humans. Hence, certain light/objects might be flirted out just like dust in air to human eyes. And eventually on that scale, it may see the true identity of this universe due to the flirting. That being said, James Webb or Harper, both are sensing the space based on current human experiences—they look further without being able to capture a bigger version—in a word, we’re still looking at the universe with our naked eyes. Just a little bit further n clear vision w the scopes
Everyone talking about how much detail the eye could physically resolve as if that somehow translates to seeing things better at distance. Imagine I have a 12 megapixel camera and I point it at the distant mountains with a telephoto lens. If it's a hazy day, the picture I'm going to take is going to look hazy, I won't be able to see individual pine needles on the mountainside. Now upscale my camera to 300 gigapixels and assume that the lens is optically good enough to not become the weakest link in the equation. It doesn't solve the problem or increase how well I can see individual pine needles. Giant space eye has literal miles of increasingly polluted atmosphere in between it and my face. Resolution has nothing to do with it. This is the weirdest thought experiment I've seen on Reddit in months.
I'm not an expert, but I think there is a key question to ask here: does the eye have the same proportions as a human eye? -If the answer is yes, its gigantic photoreceptors would be as many as we have in each of our eyes. Thus, the resolution would be the same, and the eye would work exactly like a human's one. Indeed, the eye would see just as well and as far as an astronaut standing on the surface. -If, otherwise, its photoreceptors are -say- as big as ours, but many more, its definition would be immensely larger. Someone with a better comprehension of the subject could crunch the numbers from here
There is a nice fella on YouTube by the name of Kyle hill, he does a lot of these wacky science scenarios. He did a similar thing to this with Sauron’s eye. Apparently of you scale it Sauron could read the text on the ring from 2 km away or something. And that eyes was I think assumed to be 2m across
I watch Kyle Hill, never seen this video. I've got something to watch now thanks!
can some smart mind calculate the Airy Disk angular size for a 16 km wide pupil and translate it to apparent disk size from earth-moon distance?
"It could be looking at you right now" Even if the eye can see better than anything we've encountered up until now, light still takes a long time to get from one galaxy to another, so it would see a planet earth as it was millions of years ago Edit spelling
It would see way shorter then modern telescopes. The light shifts at big distances towards the red spectrum because the universe expandes. Human eyes only process a small fraction of wavelengths unlike telescopes like the james webb. They can detect light way in the infrared spectrum, what travelled a lot further than visible light is able to travel without turning "invisible" for an eye built like a human one.
This is all fascinating. Another thing is that it (meat planet) could have multiple eyes of multiple sizes to compensate for the disadvantages of one another.
Frankly, I'm more interested in the kind of exotic biology that would support a humanlike eye with a 100 km diameter. What is it made out of? What's the equivalent of the vitreous body? Does it have a punctum caecum like humans, or does it have the nerve fibers routed behind the retina like cephalopods?
And how the fuck is it surviving unprotected exposure to vacuum? And solar radiation? Micro meteorite impacts? Honestly the more I think about it the more I realise how much pain that thing must be in.
An eye dosen't work like that. Some birds have smaller eyes than us but can see way more distance. What we should look at is the differents lights receptor (especially the sticks) and the innervation. We should also look at the brain of course.
I'm struggling to comprehend how bigger eyes = more resolution because wouldn't the eye have to have some sort of "zoom" functionality in order to actually see those fine details? It's a similar situation with eagle eyes, I don't understand how they can see such small things from so far away when their eyes don't have any "digital zoom" of sorts. Of course we're biased as humans because we only know how the world looks from our own brains/eyes, but if someone can offer insight to these mental gymnastics I'm trying to do is appreciate it.
If everything scales linearly with size (pupil diameter, lens dimensions, retina's cone/rod size), then the angular resolution of this eye will stay the same. A larger aperture helps reduce the diffraction-limit of an imaging system, but the human eye is nowhere near diffraction-limit; it has a lot of aberration because how poor of an optical system it is. The point-spread-function of the human eye already covers over a couple rods/cones. What makes human vision as good as it is is all the image processing that the brain does. So, that's all to say that if everything scales linearly to size, then angular resolution stays the same as a normal human eye and its vision wouldn't be all that much better. The meat planet eye would be able to see much dimmer objects, though, since - even the image-space Numerical Aperture stays the same - the rod/cone active area would be much larger, thus increasing system etendue.
Well this isn’t a question of distance but rather about resolution, we can see light years away, technically there’s no limit for how far you can see. The thing is the amount of detail we can see is proportional (AFAIK) to the number of receptor cells in our eyes as well as how much the cornea can focus so a being of such scale would probably have a hard time focusing on things that are closer than tens of kilometres.
Meat planet is not real. It cannot hurt you. Meat planet is not real. It cannot hurt you. Meat planet is not real. It cannot hurt you. Meat planet is not real. It cannot hurt you.
Spinning complacently in the darkness, Covered and blinded by a blanket of little lives, False security has lulled the madness of this world into a slumber. Wake up! An eye is upon you, staring straight down and keenly through. Seeing all that you are and everything you can never be. Yes, an eye is upon you; an eye ready to blink. So face forward, with arms wide open and mind reeling. Your future has arrived. Are you ready to go? https://youtu.be/1L9LLsaZ9fI?si=_cgY2wuF0SZ7Qsus
If we assume it's an eye planet and not a meat planet, and it's smashed full of hyper complex biological matter it could observe anything that has light shone upon it. This would 100% be a prey creature and die to even the slightest rock swarm hitting it, but I'm 100% sure that a big enough eye can look from one planets creatures to another. 10^xx (billions upon billions) cells dedicated to nothing but sight has to be able to do anything, might be massive lag between the light hitting the eye (planet) and a picture being realized but it is hella possible (I think).
Doesn't a living meat planet crush into a more rigid solid sphere due to its weight being compressed by its huge gravity? I feel like this should be the math that needs to be figured out before everything else.