Chapter 103 – Illusion Chamber

Sebastien

Month 2, Day 3, Wednesday 10:40 a.m.

That Wednesday, Sebastien arrived to the Natural Science classroom a few minutes early, hoping to squeeze in some of her History reading before class started. She had a new schedule to optimize her productivity. It wasn’t so much different from the old one, just more rigid and regimented, with less room for breaks, side projects, or aimlessness. It—along with the beamshell tincture—was allowing her to keep up with all of her classes and projects, but allowed barely any leeway. She was hoping that a few stolen moments of extra work here and there would allow her to get ahead enough that she could take an hour or two to herself on occasion.

Ironically, despite her underlying fatigue, the hardest part of the plan was making herself get a full eight hours of sleep every night, in two four-hour chunks with only an hour of homework slipped between them in the middle of the night. She had to force herself to cast her dreamless sleep spell and actually attempt to rest every time.

Sebastien stopped before the closed door to Professor Gnorrish’s classroom, frowning at the paper stuck to the door. “CLASS MOVED TO LIBRARY TUNNEL,” it read in big block letters. With a quick check of her pocket watch and a put-upon sigh, Sebastien spun around, hurrying to the northern edge of the Citadel.

The crystalline tunnel between the Citadel and the library was dark, letting none of the outside light through with its normal shattered prisms of color. A couple people at either end of the tunnel had opened up a part of the wall that she’d never noticed before and were messing with something within. Sebastien stepped inside warily, letting her eyes adjust to the gloom.

Gnorrish stood in discussion with a handful of other men and women in the center of the tunnel, though beyond the glint of a faculty token it was too dim to make most of them out.

Sebastien sat cross-legged against the wall, imitating the handful of other students who had arrived before her. Her eyes were slowly adjusting, but it was far too dim to read, so she tried to let her mind relax. She was still buzzing with energy from her morning dose of the beamshell tincture, which tended to give her a feeling of bottled up energy that needed to be released somewhere.

Her eyes were attracted to a familiar silhouette as one of the professors that had been talking with Gnorrish turned in her direction.

“What are you doing here?” Sebastien blurted out to Professor Lacer, her voice entirely too loud, drawing the attention of the other professors and students.

Her eyes had adjusted well enough to the light to see the scathing look he sent her, and she ducked her head in an apologetic bow. “I meant, I’m surprised to see you, Professor Lacer,” she amended in a much softer tone.

“I am here to do a favor for a fellow professor, and not incidentally, for my apprentice as well,” he drawled.

She wondered what kind of favor would require so many of the faculty.

Reading the curiosity on her face, Lacer simply said, “You will see,” and moved to stand nearby, his expression clearly stating that the conversation was over and anyone who disturbed him with idle chitchat would feel his wrath.

The other professors split up as well, at mostly equidistant points along the length of the tunnel.

When Damien and Ana arrived, they looked around with curiosity. “What are we doing here?” Damien asked, the question aimed toward no one in particular.

“This is a simulation chamber focused on visual illusions,” Ana said. “I imagine there will be some sort of demonstration.”

Gnorrish loudly instructed the students to arrange themselves into groups of at least five, but no more than ten, and join a professor.

Sebastien’s trio was quickly joined by a handful of random other students, meaning that the rest of Damien and Ana’s friends had to form their own group, despite Alec’s muttered desire to simply force the other students to leave.

Sebastien tapped her fingers against her knee rapidly, letting Damien and Ana’s light chatter flow over her head.

Finally, Gnorrish began his lecture, walking slowly between the groups of students along the length of the tunnel, a ball of light floating above his head. His booming voice carried easily. “The next few weeks of this class will be an exploration of light. Or, more correctly, an exploration of the electromagnetic field that includes visible light. It is an important research area in modern natural science for multiple reasons. Not only is light a freely available energy source for your spells—in some cases even more abundant or useful than heat—it is both versatile and powerful. I believe it has the potential to do so much more, and as it is considered one of the more difficult energy sources to channel, we will be spending extra time learning about it.”

Sebastien tracked Gnorrish’s slow pace with her eyes, unblinking, as if she could suck the knowledge out of the man with her eagerness alone. ‘The more I understand through the concepts of natural science, the better control I’ll have with all magical applications that use light.

Lifting his hands to the sky, Gnorrish paused, and then, with a dramatic flourish like a conductor before an orchestra, he dropped them.

An illusion sprang to life in front of each student group, not unlike what they were learning to do in Practical Casting, but somehow, perhaps because of the surrounding darkness, seeming more tangible. “Behold! One of the many utilizations of light magic,” Gnorrish trumpeted, throwing his arms wide with a grin.

The illusion spell displayed a stack of waving lines. They all seemed to be moving, flowing, from left to right, with the ones at the top at such a gentle slope they barely seemed to rise or fall at all, and the ones at the bottom in such a zig-zagging frenzy that they seemed almost a solid scrunch of light.

Sebastien peeked toward Professor Lacer, who had once hand pressed against a section of the tunnel wall and the other curled around his Conduit, his focus on the illusion hanging in the air before them. The other professors seemed to be doing the same, and though the image in front of each group was almost identical, Sebastien thought theirs seemed more tangible than most. As if she would feel the lines if she reached out to touch them.

“Light is a form of energy, and it travels in waves,” Gnorrish said. “There is no difference between light and the rest of electromagnetic radiation. Electromagnetic waves, just like ocean waves, have different wavelengths, the distance between their peak and trough ranging from hundredths, maybe even thousands the width of a pinhead, to miles wide. I suspect there may be no limit to the range, one end approaching an infinitely small distance and the other an infinitely large one, but we have not developed the measuring tools or spells to tell if my theory holds weight.” Gnorrish paused, his eyes trailing over the students to gauge their response. “Light with a shorter wavelength has more energy, while light with a longer wavelength has less. Imagine you’re in a boat on the ocean. If each wave is so far apart that you rise and fall over them so gently it’s barely noticeable, you might say the waves were low-energy. If you were in the middle of a storm, with your boat pitching and swaying so steeply that you needed to grab onto something to keep from being thrown off the side…” Gnorrish mimed the wild scramble for purchase against the pitching deck of a boat, to the laughter of many of his students. “Those are high-energy.”

Gnorrish stopped his wild flailing, pointing to a very small section of light waves in the middle of the illusion, which took on a rainbow spectrum. “Our eyes and brains are adapted to perceive this range of wavelengths. Can anyone tell me what’s special about this range, which we call ‘light?’”

Students shifted uncomfortably as his eyes roved over them, but no one spoke.

He looked to Sebastien.

She shook her head to silently signify that she didn’t know, either, but to her dismay he called, “Mr. Siverling! What do you think?”

Her gaze flicked to Professor Lacer, then back to Gnorrish. She opened her mouth to admit she didn’t know, but realized he had already given them the answer. “The only thing special about it is that we can all see it, and we gave it a label called ‘light.’”

Gnorrish lifted his hands, bobbing them back and forth as if weighing something on an invisible scale. “That’s not entirely wrong, but not entirely right, either. The leading theory is that we see this part of the spectrum because it’s the most relevant for us. The majority of our sun’s radiation happens to fall in that part of the spectrum. There’s a lot more of these wavelengths consistently available. Another theory is that good color vision is important for animals—such as humans—that subsist largely on fruits and vegetables, rather than as carnivores, many of which are color blind. It could also be because visible light is the only set of electromagnetic radiation that propagates well in water, where it is theorized all the mortal races rose from. Yet another theory is that radiation in that part of the spectrum is easily stopped by matter. If we had evolved to ‘see’ using super-long wavelength radiation, for instance, which can pass through matter, we’d be bumping into trees and falling into holes because they’d be invisible to us!”

With another conductor’s wave, Gnorrish changed the illusion to show a tree standing before a huge eyeball, which was sliced in half so they could see its pieces and what was happening inside it. “Thousands of years ago, people thought that sight came from our eyeballs sending out tiny little information-gathering probes, which returned with the images we see.” The eyeball shot out little birds, which landed on the tree and then returned, flying back through the pupil. “Of course, we know today that sight comes from light entering our eyes, passing through our pupil, and hitting the retina, which lines the back of our eyeballs.”

The illusion changed to show multiple rays of light hitting the illusory eyeball, some managing to enter through the pupil and others bouncing off. “The retina contains two types of photoreceptors, both rods and cones. Rods work at very low levels of light and allow us to see in greyscale at night. Cones require a lot more light to activate, and they are used to see color.” With a spreading motion of Gnorrish’s arms, as if he were swimming through the air, the eyeball expanded to show the details. “We have three types of cones: blue, green, and red, and all the colors we perceive are some variation of or a mix of those. Did you know that human infants only perceive black, white, and grey, which will later become red?”

Sebastien reached out, letting the tips of her fingers trail over the gigantic slice of eyeball, and almost jumped when it rotated away from her finger as if she’d actually touched it. She snatched her hand back, rubbing the tips of her fingers—which hadn’t felt anything—and looked to Professor Lacer. She wasn’t sure if she was imagining the almost imperceptible expression of smugness on his face, but her attention was soon enough drawn back to the lecture.

“It’s not until about five months of age when we begin to see all the colors. Prognos children, however, see all colors from birth.” The illusion morphed into a series of red and green balls of slightly different shades. “And how do you know that the ‘red’ you see is exactly the same as the ‘red’ someone else sees? The colors themselves don’t exist, only the electromagnetic radiation. The color is in your mind. Studies with shared perception spells have proven that even among humans, not everyone sees the same colors. Some are varying degrees of color-blind, unable to distinguish between different colors, and some women can see even more colors differentiations than the rest of us.”

With a snap of his fingers, the balls all adjusted to be the same color, to Sebastien’s eye, but Gnorrish said, “About ten percent of women can distinguish between these shades of red.”

Sebastien squinted, wondering if, in her other body, she would be able to tell them apart.

“Now, some of you might wonder, why does understanding all this matter? What kinds of magic might use this knowledge, other than the illusion spell we’ve just demonstrated?” This time, he didn’t immediately answer the question himself, staring at them expectantly.

As student raised her hand, and when Gnorrish pointed to her, said, “Well, shared perception spells, like you were saying.”

He nodded. “What else?”

Sebastien raised her hand, but was preempted by another student. “The eagle vision potion and spell,” the man said. “Darkvision magic, too.”

“Some magical beasts are really attracted to the color red,” another young man piped up without waiting to be called on. “Maybe it’s the only color they can see? That’s important to know if you want to survive in the wilds.”

“Image-capturing artifacts,” Ana said. “They work on a similar principle to the retina, but instead of sending signals to the brain, they affect the photo disk, changing its shade according to the level of energy in the captured light. They end up creating a black-and-white version that has exactly the opposite values of darkness and light from reality, which allows the correct-value image to be transferred to photo paper with the help of some alchemical solutions.”

Gnorrish gave Ana a thumbs-up. “Very good, Miss Gervin. I see you’ve done your research on the latest advancements in that field, and let me point out that it is possible only because of a greater understanding of natural science. Those artifacts use the principles of transmutation. Any more ideas?”

“A temporary blindness hex,” Sebastien offered, joining the trend of blurting out answers. “You could interrupt someone’s sight without permanently damaging them just by keeping light from hitting their retina.”

It was also useful to understand because it meant that the philtre of darkness she’d found so useful was catching, and perhaps absorbing, all the visible light that entered it. But an opponent might be able to circumvent the clouds of darkness with a spell that allowed them to see a slightly broader spectrum. Or, with this understanding, she could make the philtre catch even non-visible radiation the next time she brewed it, to ward against someone with an otherwise clever counter-spell.

Damien leaned forward. “Hidden messages! If you could tune a spell’s output to create a specific wavelength, you could have a receiver spell set up to recognize that exact wavelength—ideally one of the invisible ones—and you could use it to send pre-set signals.”

Though Professor Lacer seemed uniformly unimpressed with the students’ offerings, Gnorrish was pleased. “All good ideas!” One hand sketched out a wide arc, and the illusions morphed into bright light passing through a prism, splitting into the full spectrum of color. The rainbow beam stood out starkly against the relative darkness, revealing fine particles of dust in the air.

“This is what it looks like when you separate light into its different wavelengths, which is easy to do using a prism. Humans can see seven distinct colors on our tiny spectrum of electromagnetic perception. Right on the edge, below violet, there is another color.” He paused dramatically. “Ultraviolet is the wavelength just slightly shorter—and higher energy—than violet. Some creatures, such as bees and butterflies can see ultraviolet. It’s useful for them to be able to easily identify nectar in flowers. Prognos can also see it. They say it’s beautiful.” He paused wistfully for a moment, staring at the scattered rainbow prism. “Other creatures can see further on the spectrum in the other direction, known as infra-red, which allows them to identify heat sources even in relative darkness, making them wonderful predators.”

As if reading Sebastien’s mind, Gnorrish answered her immediate question. “Attempts have been made to create spells that allow people to temporarily see beyond our normal visible spectrum, but they haven’t made it into general use, even among adventurers who would seem to particularly benefit from additional sensory abilities. Why?” He didn’t pause long enough for anyone to attempt an answer. “Basically, these spells have too many side effects. Synesthesia, where the brain confuses ones sensory pathway with another and you begin to feel, taste, or smell colors. Other side effects are confusion, disorientation, and pain—in some cases to the point of causing mental trauma. And in a few unfortunate cases, people have experienced rupturing of the vessels of the eye or brain due to incompatibility and overstimulation. Please do not experiment with this.”

He paused to let that warning sink in, meeting students’ gazes again to impress his seriousness upon them. “There are some potions that work safely, particularly for the infra-red wavelengths, but they require an ongoing regimen over several months to adapt the brain to the expanded sense, and then continued upkeep to maintain that adaption, which is very expensive and hasslesome, especially in the beginning.”

He turned back to the rainbow prism, which returned to the waving spectrum of lines with that small section in the middle rushing through the colors of a rainbow. “To reiterate, our eyes capture the majority of the light that is thrown at us by our sun, but not the majority of the entire range of light.”

He paused for a moment, using a handkerchief to wipe away the sweat on his forehead and take a few deep breaths. “Now, you’ve all heard of refraction, and seen examples of it. Refraction happens when electromagnetic radiation passes through a substance with a different density, at an angle. A medium such as water is more dense than air. As light enters, it slows down. But the light doesn’t change energy; you’ve all seen that light doesn’t change color just because it passes through water or clear glass. What does change is the distance between the wavefronts.” The illusion morphed to show a series of waves hitting a glass block straight-on. As they passed through it, they grew much closer together, stretching out again as they exited. The block slowly rotated, and the waves within angled with it, straightening out again as they exited the block on the other side—but now slightly lower down.

“Imagine a sheet of metal is passing through the air toward you. It’s too stiff to bend. You press your finger against one side of it and apply a little resistance. The part you pressed on is suddenly moving slower, and so the whole sheet of metal pivots toward that side, and is now moving at an angle. The light has just entered a substance with a different density. Now, say someone else is behind you, and when the metal sheet reaches them, they poke the other side and straighten the metal sheet out again, sending it off in the same direction but at a slightly different location than its original trajectory would have caused. The light has just exited the substance. Refraction works kind of like that, and its why you’ll only see refraction when light enters or exits a substance at an angle. The really interesting thing is, that angle doesn’t need to be a straight line. It can be curved. This is the concept that optical lenses are based on, allowing the creation of eyeglasses, telescopes, and even your own eyeballs.”

Instead of undulating waves, the light changed to be depicted by flat sheets passing through the block of glass.

Remembering her earlier attempt, Sebastien reached out to the block, moving slowly and telegraphing her intention. She adjusted its angle and watched as the representation of refracted light moved with it, forced to turn as it passed through, and then allowed to straighten as it exited.

The students around her gasped. For once, she agreed with the general sentiment. ‘This is amazing!

Gnorrish continued as some of the other groups started to pick up on the true nature of this lecture and the utility of the simulation chamber. “Now, when the substance is too dense for light to propagate within, instead of refracting, it reflects. Glass, water, and other semi-transparent substances are only reflecting a small percentage of the overall light that hits them, but when their surfaces are smooth enough, it allows a mirror-like reflection. In fact, if any substance was smooth enough, you would get that same mirror-image reflection, because there’s no natural substance with complete transparency.”

He again asked for examples of magical uses for this knowledge.

“Invisibility spells,” a young woman piped up immediately. “You could just bend light around yourself so people see whatever’s behind you.”

A young man lifted his hand. “That works for illusions, too, making people think something is there when it really isn’t.”

Gnorrish nodded, pointing at the man as he replied. “That effect is encountered in nature through mirages, including the superior mirage known as the Fata Morgana, which have created illusions of floating islands that lure sailors to their deaths. It’s also why, in the morning, you can see the edge of the sun before it has geometrically risen above the horizon. Continue.”

A girl with a clear, jelly-like eel from the Plane of Water winding around her damp shoulders, marking her as a witch, said, “Healing spells to mend or replace eyeballs. Or augmenting spells to improve the distance or ocular precision, even. Eagle vision could be permanent, if you did it right.”

A man, scribbling notes without looking up, said, “It has applications in sound spells. Those are waves, too. It could be used to develop long-distance communication spells, or even targeted communication spells, to give information to allies while excluding enemies without the need of any sympathetic connection.”

It’s probably also applicable to wards against certain kinds of divination or revealing spells.’ Sebastien thought. ‘Reflect or redirect the magical waves. I wonder if my ward uses any of these principles?

Damien raised his hand, speaking before Gnorrish had a chance to point to him. “There’s a shield spell that looks like a super-smooth silver mirror and reflects all kinds of energy attacks. Aberford Thorndyke used it to survive being thrown into a pool of lava. And maybe you could make a spell that turns infra-red radiation into red light, to help illuminate the dark!”

Some of the students laughed, but Gnorrish only grinned wider, “Indeed, both very creative applications of the principle we’ve discussed.”

Sundered zones,’ Sebastien thought. She only realized she must have said it aloud when Damien’s head snapped around to look at her. She shrugged. “They’re obviously reflecting all light, to be that perfectly white, and magical effects can’t pass through them.” It didn’t explain, however, how an Aberrant like Red Sage managed to affect the world through its prophecies, if the sundered zone was truly keeping all magical effects from entering or exiting. Information about that barrier spell was highly restricted, so she could only speculate about how it, or the Aberrants contained within them, worked.

Gnorrish continued lecturing, explaining how refraction worked in mirages, rainbows, sunsets and sunrises, and various different lens shapes, with illusory illustrations for all of them. He even used a couple equations to explain things for the more mathematically inclined.

Then he let them play with light themselves, setting them various tasks with light sources, lenses, and different substances. Sebastien took charge without allowing any dissent, using hand motions and the occasional verbal request to Professor Lacer to change brightness, angles, and shapes.

Under her guidance, her group created their own simple eyeball, then both a telescope and a microscope, and some fun-house mirrors that morphed their reflections in various ways. They simulated infra-red vision in one of the mirrors, and at her request, Professor Lacer attempted to make a ball of light give off only ultraviolet radiation just on the edge of visible light, which was very strange and caused normally invisible smears and splatters on their clothes and surroundings to stand out with a peculiar glow.

By the time class ended, they were trying to produce their own mini Fata Morgana mirage of a floating island in the sky, though having some trouble with the delicate balance of the required conditions.

Sebastien had lost herself in it like a gleeful child playing with a fascinating toy, and looked up as the illusion dispersed and the walls of the tunnel lightened, allowing the weak sunlight to come through in blinding rainbow-colored sprays and sparkles.

All of the professors looked exhausted. Professor Gnorrish didn’t even have the energy to raise his voice or wave his arms about as he dismissed them. Even Professor Lacer had a faint sheen of sweat on his brow, but when he met Sebastien’s gaze and her incandescent smile, the corners of his lips twitched up faintly in response.

Author Note 4/21:

Got the site up an running properly again, and I’m also going to be making some tweaks to improve user-friendliness in a couple areas over the next week or so.

This chapter, and following chapters related to it, took a TON of research about how light actually works. Just like pretty much everyone else in the world, I know a lot of keywords and can place those keywords into the correct position in a sentence to get good grades on a test, but I actually UNDERSTAND almost nothing. With all the research I did, I have a slightly better grasp on how light works…but I don’t actually understand what it is. There’s still a lot more for me to learn, but I doubt I’ll be able to actually understand, because I’m pretty sure no one actually understands light. Maybe one day.

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Isa Lumitus
Isa Lumitus
23 hours ago
Reply to  Azalea Ellis

Nifty! I refused to comment here earlier, given the way the site destroyed my attempts at formatting.

Melinda Hutson
1 day ago

I’m really enjoying the book and will of course buy a copy when the entire thing is out. I know more about electromagnetic waves than I do about water waves, but I think your analogy is flawed and you might want to remove the bits about water waves. Small ripples do not carry the same energy as large waves created by storms and hurricanes. Partly this is because water waves (unlike EM waves) require a medium (water). Stolen from the internet: “The energy in an ocean wave consists of both the kinetic energy of the moving water, and the potential energy associated with the up-and-down peaks and troughs of the sea water above and below average sea level.” Tsunamis (which have enough energy to move quite a distance inland, picking up buildings as they go) have wave depths that extend to the ocean floor. Another stolen quote from the internet: “A further feature of tsunami waves is that these high-speed waves lose very little energy as they travel across the open ocean, because the rate at which a wave loses its energy is inversely related to its wave length.” EM waves don’t lose energy as a function of their wavelength. The energy is spread out over ever increasing surface area. Sorry. You can delete this post. I’m not trying to be pendantic; this just pulled me out of the chapter as I was reading.

Qwat
Qwat
1 day ago
Reply to  Melinda Hutson

For me the blurring of material waves and em waves is not that bothering, as I could imagine they haven’t gotten that far regarding scientific knowledge. For a long time it was assumed that there is an underlying ‘material’ (aether) that transmits these waves similar to the actual material ones. I think it was the theory of relativity that contradicted that it can not be an actual material, but I might be incorrect.

Qwat
Qwat
1 day ago

Hello, I liked the chapter a lot, but there is one slight inconsistency in the explanation of the teacher:
Imagine you stopped the waves in the ship example, so they do not change in time, they are basically a landscape. Then they have the same wavelength, but do not carry the same energy as when they were bouncing fast. (Though their amplitude and material are same.) Now if you slowly speed them up, you can feel that the energy is increasing. Generally this would not bother me but at the refraction explanation the teacher says that it does not lose its energy in the material, while stating that the wavelength is not the same, contradicting his initial explanation.
So he should know, that it is either determined by frequency, or by velocity and wavelength together, if you disregard amplitude.

Otherwise everything is very neat.

miles
miles
1 day ago

>electromagnetic field

I think you meant spectrum. An electromagnetic field is just what the electic and magnetic waves are doing in a particular section of space.

Isa Lumitus
Isa Lumitus
23 hours ago

Hmm… You know, I’ve got my own theory on why we see the color range we do: It’s what makes it through the atmosphere best. Go too far into the UV or IR range, and the intensity of sunlight starts falling off.

Also, I think I could make a better spell/potion for seeing IR. Instead of adding that type of cone, I’d temporarily replace the red cones. All colors would look wrong, but I wouldn’t have to make any changes to my nerves or brain.

Isa Lumitus
Isa Lumitus
21 hours ago
Reply to  Isa Lumitus

Having thought about it… I’m not sure that would work. Just because the eye has receptors for IR doesn’t mean it that wavelength wouldn’t be blocked by the vitreous humor or lens. That’s why we can’t see UV, after all.

Speaking of… If I ever get cataracts irl, I want to go with an option that will let me see UV. That’d be either really thick glasses, or some sort of synthetic cornea.

AVR
AVR
19 hours ago
Reply to  Isa Lumitus

Near IR, up to about twice the wavelength of visible light isn’t blocked by water/parts of your eyeball. OTOH that’s not different enough to ordinary light to be all that interesting; the IR radiation from ordinary warm objects is mainly in the long IR band. It might be a way around spells blocking visible light though.

cucio
cucio
23 hours ago

Don’t get me wrong, I love PGtS, but I’m puzzled about this chapter.

While the effort in researching and putting together an optics primer is not small and should be properly appreciated, I’m not sure this chapter contributes enough to the narrative to belong in a fantasy book. I have a good foundation on the subject, so I found myself just speed-skimming through and all I have to show for these few thousands words is “Sebastien sat through an elementary lesson in optics with cool simulation tools.” I wonder what readers not familiar with the topic that are here for the magic and adventure will think of this chapter.

Regarding the topic of “being pretty sure about no one understanding light”, I found that statement a bit short-sighted, if you’ll pardon the pun 😉 . Physicists who make it their object of study would probably object.

I mean, if we get philosophical, obviously no one understands everything about anything, you can always dig deeper. You could say things like “no one understands literature”, “no one understands bread baking”, etc. and it’d be technically true. But understanding light is pretty damn useful and experiments in optics have a long history, so the knowledge people like physicists and medical researchers have accumulated about it through the centuries is *vast*

As an example, just recently a group of astronomers managed to synthesize an image of the gas cloud surrounding the black hole at the center of our galaxy using a network of eight radio telescopes distributed all around the planet. Taking into account the distances involved, relativistic effects, interference sources all along the way, all the processing to combine the information conveyed by the handful of photons coming from the source that hit our tiny rock… not half bad understanding of light, I’d say.