“I approached the location of the suspected smugglers with a reasonable level of caution for the expected threat level. However, as I entered the hut that was shielded from both remote viewing and apparition, I was hit by Expelliarmus and Petrificus Totalus spells from two directions and found myself disarmed and immobile on the floor, as four assailants revealed themselves and started describing what they planned to do to me next. I used wandless magic to touch space geometry and applied crushing force and extreme rotational swirl. As they died, I was released from the body-bind curse and immediately called my boss for help”, Hermione finished her debriefing before the Wizengamot.

“May I assume that the boss in question was Lady Lyra Malfoy-Potter, and that she was the one who taught you this form of magic?”, Minister Shacklebolt inquired.

“That is correct, Your Honour”, she nodded.

“Lady Lyra, do you have anything to add to this statement?”, Minister turned to the young blonde.

“No, Minister”, she replied. “It is both accurate and specific. But I would add that my husband and I already implemented steps to assure that Aurors do not end up in similar high-risk situations in the future. We decided it would be better to overestimate than underestimate the level of threat, because this time we got lucky that the sole Auror we sent to investigate happened to be immensely overpowered for the task. A less powerful magical user would be killed and it would have been a tragedy”, she finished gravely.

“Can you please inform us of those steps?”, the Minister raised an eyebrow.

“No”, she turned her head decisively. “It is a matter of national security. If we reveal our tactical parameters to the public, the criminals will become aware of them and we will expose our officers to mortal danger”.

The Minister smiled. “Thank you for your time and for your service. Does anyone have questions?”, he turned to the judges.

“We understand that you taught your magical method to your sister of choice. Is there a reason why you restrict sharing your knowledge?”, an elderly Witch inquired.

“Yes, Your Honour”, Lyra nodded. “I taught my husband, Hermione and Viktor, because they are members of my family, I know them to be immensely honourable, reliable, disciplined and virtuous, and I trust them implicitly. Outside that circle, I have no intention of sharing my knowledge either now, or at any point in the future”.

“This is an incredible contribution to human understanding of magic”, an elderly judge spoke out. “Absolutely worthy of Order of Merlin, first class, if you documented and shared your discoveries, and it would certainly advance our society immensely were it widespread”.

“And it would destroy our society outright if some new Voldemort or Grindelwald happened to get his hands on it”, Lyra countered, waiting for the murmur of consternation to dissipate. “I decided to share it with people whom I already trust with my life, and share my life with. Every single one of them was at one point or another in a position to have me perfectly helpless under their protection and care. They are also the people who will listen to my warnings and obey them without question. I don’t know if you saw the pictures of the aftermath of Lady Hermione’s intervention?”, she raised her eyebrows questioningly, and few nods of assent were seen in the audience.

“Well, if you saw what she did to those criminals, while wandless and bound, lying on the floor unable to move even her eyes, can you imagine what one of those criminals could do to innocent people if they learned this method of magic? Yes, I see that you understand. All three people I taught are Aurors. Harry and Hermione were awarded Order of Merlin, first class, for their contribution to ending the last war. They are the most fundamentally trustworthy people in the world. Viktor is Hermione’s husband and my brother of choice, whom I trust with my life. I trusted them with the most lethal knowledge in the world, and what have you seen so far as the consequence? Hermione liquified four hardened criminals in line of duty. Harry broke himself and Viktor out of a hundred kilometers per hour death dive on brooms. Had some untrustworthy person learned that knowledge, they could do absolutely whatever they wanted and nobody could stop them”, she concluded. “So, regardless of my likely loss of state honours for magical contributions, I’m afraid I couldn’t sleep peacefully at night knowing that I released this potential horror to the public”, she concluded.

“Thank you for your time, my Lady, and also for your service”, concluded the Minister.

…

“I can’t believe it”, Hermione read the Daily Prophet over breakfast. “They awarded you the Order of Merlin, first class, for immense contribution to both knowledge of magic and to national security”, she giggled. “Also, they issued an edict whereby you hold the exclusive stewardship of this knowledge in the name of the Ministry, and have exclusive authority of choosing whom to share it with”.

“That settles it, I guess”, Lyra sipped her white coffee and smiled.

“OK, listen up”, Harry clapped his hands, and his family gathered in front of him. It was a very nice day in the woods, and they really missed stretching their legs outside.

“We lucked out with Hermione this time, but imagine if they were leading with something deadly. Doesn’t have to be Avada Kedavra, it could have been Sectumsempra, or Reducto, or even Stupefy. There are terrible spells out there, things that amputate limbs, destroy minds, wipe memory. She ended up bound and disarmed, but conscious, able to work wandless magic. They could have hit her with something that would knock her out, and then transported her who knows where, and who knows what they would have done to her before we could intervene, or she could do something about it. We messed up, and we got lucky”.

They all nodded in agreement. “So, let’s see the post mortem analysis here. I’ll start with myself. I misjudged the threat level. The moment I couldn’t remote view the situation in the field, I should have aborted the mission and sent at least three people, heavily shielded, with smoke grenades with disabling potion, knocked them all out first and since they made sure nobody can disapparate from there, that would have worked. I failed and it could’ve got Hermione killed”.

“I didn’t create spells for her to use wandlessly in an emergency. Quick stuff that would instantly pause time for every living being around her, another spell that would have them bound, disarmed, unconscious and ready for transport. A rescue spell that would render her instantly invisible, shielded, that would inactivate all magic that was cast upon her in the last hour, and so on. And I also underestimated the threat. I should have seen the signs – the hut was too far, too well shielded to be a mere smugglers’ nest. I’m giving myself a failing grade as well, and the fact Hermione made it safely out is not due to any help from me”, Lyra finished.

“I didn’t go with her despite having a bad feeling. I dismissed it because I wanted her to grow her confidence by doing an easy job unassisted. I almost got my wife killed because I was slacking”, Viktor nodded gravely.

“I didn’t have a shield charm on me, or my clothes. I believed it would be easy despite there being no actual sign confirming it. I took absence of immediate problems as evidence of safety. I had a feeling there were people in the hut when I entered, and I didn’t immediately act on it. And when I was hit and on the floor, I panicked and used the easiest and deadliest form of magical attack that I could pull off, when Expelliarmus would have rendered them all harmless as the first move, giving me time for the second move. I convinced myself it would be easy, and when it wasn’t, I went for the nuclear option”, Hermione smiled.

“Nuclear?”, Viktor raised an eyebrow.

“Muggles have nuclear bombs that can instantly destroy whole cities with everybody in them. It’s the weapon of last resort they never want to use because there’s no going back after that – and the enemies have them as well, and it’s expected that they will all get killed in the retaliatory strike”, she explained. “Going for the nuclear option means panicking and overreacting, which I did”.

“OK, it’s good to know that we are all on the same page. Now, let’s see what we did well. I had everybody on stand by, ready to intervene on call. That worked well later on. Also, I handled the aftermath well. Other than that, I can’t think of anything”, Harry smiled bitterly.

“I taught her wandless magic and we made that communication bracelet spell that used to be a baby alarm, but now she used it to call for help”, Lyra nodded.

“I didn’t do anything right. I stood there like a fool instead of being with her, she did all the work, and I gave an interview later glazing over our fuckup, acting as if she had it under control”, Viktor was remorseful.

“I learned from Lyra attentively enough that I could use wandless spatial compression and disruption on multiple targets at once. I also called for help as soon as I physically could”, Hermione concluded.

“So, let’s summarise. We need to take things more seriously and not ignore signs of danger. We don’t send people alone into danger. We need communication devices, similar to that bracelet of yours, but something we can give out and remove, not as permanent, something similar to the muggle radio. Something that transmits voice to the central at all times, and possibly the visuals. If the signal interrupts for whatever reason, we immediately send support. We need those spells Lyra talked about, quick, almost automated action along predictable lines, and we need to practice with those until it’s our second nature. Also, when anti-apparition and anti-surveillance magic is detected, we interpret it in the most paranoid way possible, assuming that five death eaters under invisibility cloaks are about to fire Avada Kedavra the moment someone enters”, Harry concluded.

“I’ll start working on it immediately”, Lyra nodded and kissed his hand.

“I can do the communication artefacts so that Lyra doesn’t have to do all the work”, Hermione smiled.

…

“I just remembered something. In the forbidden forest, I had a situation where I was overwhelmed by waves and waves of Acromantulas charging at me, and I just thought about how I would deal with that now and I honestly don’t know. I would do a perimeter freeze but I would be instantly overwhelmed by new enemies. Any barrier would hold for a while, and then I would be overwhelmed. If something like that happened within an anti-apparition zone, like that island within the cave surrounded by the Inferi, I would be dead”, Harry told his wife as they were preparing for sleep.

“That’s a good point”, she nodded. “We always assume human threats, but I think those might increasingly become the lesser concern, and we might instead be forced to deal with dangerous creatures. Basilisks, Dragons, Acromantulas, and who knows what. I need to take this into account when designing the spells”.

…

“Good morning boys and girl, I am putting you back to school”, Lyra smiled as she approached the breakfast table with her coffee and croissants. It’s been a week since their post mortem, and she was busy.

“Here’s a list of spells I made for you, with descriptions and instructions”, she handed them a piece of parchment, which Hermione immediately duplicated so that each of them would have one.

“Festino, Tranquillo, Deleo, Effugio, Pax, Zona stasis, Lux propria”, Viktor read the spells out loud. “You’re such an incredible overachiever, sis”, he smiled.

She shrugged and smiled. “It would be about time, since I almost got your wife killed by being the opposite”.

“What do they do?”, Harry met her eyes.

“Festino makes your personal time go faster, so the world looks like it’s in slow motion while you move. It gives you a short burst, about a minute, but in that minute you can do whatever and nobody can oppose you”, she started.

“Woah”, Viktor was amazed. “So it basically feels like Impedimenta cast on the rest of the world, while you either escape, or mop them up. This is an incredible weapon. We have to keep this to ourselves because if anyone else uses it, it could have terrible consequences”, he warned.

“Absolutely, but it’s a spell that can be cast only wandlessly by touching magic directly, and we’re keeping that within our intimate family circle because spreading it out is just a horrible idea”, Lyra nodded. “But let me continue. Tranquillo is the opposite – it doesn’t accelerate you, it slows down everything in the area to a standstill, or close enough. That’s what I used without a spell in Knockturn Alley. It can affect the target area or individual people, but once it’s applied, new people entering the area won’t be frozen in time, which is good when our people come to support us, and bad if the hordes of enemies are rushing to overwhelm us, so there’s that”, she nodded seriously.

“So this means we can now trivially cast that time freeze you did there?”, Hermione wondered.

“Yes. That’s identical magic, only invoked by a spell. Next, Deleo. It’s like Reducto, only focused on magic. Never do this inside the house or any other magical place because this will neutralise all existing spells, regardless of who cast them. The only thing that overrides it is deeper authority; you can’t, for instance, enter someone’s home and negate their protective spells unless you are specifically on a mission as Aurors, which gives you deeper authority and then you can basically override everything, as long as it is related to the specific mission you are on. The deeper magic is specific regarding this. You’re just not allowed to abuse it, but when you have authority of your office, you can use it to delete all magical wards on a specific place”, she warned.

“Woah. I wish I had this in that cave where Voldemort kept the medallion”, Harry mused. “I could have inactivated all that horrible stuff, since Voldemort had no inherent authority over the place”.

“Exactly”, his wife nodded, “And this is what it’s meant to do. Also, for neutralising anti-apparition and anti-surveillance spells such as those Hermione had to face. Next, Effugio. It allows you to escape to the last location of perfect safety. This will be either home, or with people you love. It picks the location specific to the caster, from their own soul, and cuts through all anti-apparition spells in existence with absolute priority. It allows you to escape from traps such as the one we allowed Hermione to walk into. It also casts a temporary time freeze during the disapparition process so that we wouldn’t have situations like aunt Bella throwing a knife and killing Dobby”, she reminisced with sadness.

“That stuff is incredibly useful, sis. You’re a genius”, Viktor was impressed.

She blushed slightly. “Thank you. Next, there’s Pax. It strikes either a zone, or individual targets, always excluding the caster, and disarms and petrifies everybody within the area of effect. It’s not capable of cutting through all protective charms, so be careful about that”, she smiled.

“Useful”, Hermione nodded. “But if someone has a Protego artefact on them, you need to be ready for immediate follow-up”.

“Exactly”, Lyra confirmed. “However, it is something I would recommend as a second spell, after time-freezing them with Tranquillo, or speeding yourself up with Festino. It allows you to wrap them up quickly, but it’s not the first spell I would use. The next one is Zona stasis, and it’s very much like Tranquillo, only it works on an area, not people, which makes is incredibly tricky to use. It makes the place work on slowed down time for all who enter it. Harry gave me the idea when he reminded me of the time he was rushed by a deluge of Acromantulas in the forbidden forest, and this would essentially time-freeze everybody who enters the area of effect. That, of course, includes the caster, his friends and all reinforcements. The point of this is to make a time-frozen sphere around yourself so that the enemies can’t touch you regardless of how many there are, so that you have the time to disapparate from the area where you’re overwhelmed, or, if that’s not possible, apply the next spell that would kill all the frozen enemies and figure out your next move when the spell wears out, which will be five minutes or so”, she finished.

“This is incredibly impressive”, Harry smiled at his true love. “Your new spells are among the most impressive offensive and defensive magic I’ve ever seen”, he nodded.

“The last spell is Lux propria, and it’s like a combination of the Peruvian instant darkness powder and the Hand of Glory, that I used in that very dark hour of Dumbledore’s death”, she shivered. “When you activate that spell, it creates an area of effect around you where everybody else will be temporarily blind, nobody outside the area can see into it, and only the caster sees normally. It allows you to escape or infiltrate”.

“We need to practice those until they are our second nature, because I already forgot half of them”, Viktor nodded. “But honestly, Lyra, what you did with this in a mere week, I have no words”, he looked at his sister adoringly, and he could tell that Harry and Hermione felt the same.

“You’re awesome and I worship you”, Hermione whispered in Lyra’s ear as they hugged, and Lyra hid her embarrassment in Hermione’s hair.

“Nope”, Lyra smiled mischievously. “Only Harry is allowed to tickle me in my tickliest spots. You’re allowed to hold me while he does it, though”, she winked at Hermione while both she and Harry blushed like two tomatoes.

“What are you people up to so early in the morning?”, Viktor came with his coffee cup, finding Lyra in a very good mood while Harry and Hermione looked like they wanted the ground to swallow them whole.

“What did you do to them, sis?”, he laughed.

“Oh, a little payback”, she played innocent. “You know how she likes to tease me until I hide my face under something”.

“Oh”, he realised it must be about the goddess thing. “Well, serves them right. I’d never call you my goddess to your face. I just pray to you at a private altar in my room”, he snickered.

Hermione gave him a high five. “That’s my husband”.

Lyra hid her face into Harry’s chest and whispered “It’s all your fault”. He snickered and kissed her head.

“Lyra was actually leaving us dumbfounded with her understanding of things and I couldn’t resist, because honestly and jokes aside, she’s so impressive I feel like melting into a puddle at her feet, and I was teasing her to hide my embarrassment”, she told Viktor.

“I just figured out something else, while we’re at it”, Lyra was now more serious. “The muggles have the concept of meaning inverted, from us”, she mused. “To them, meaning is an emergent property of human brain, which is an emergent property of chemistry and physics, and the physical world is a reality, that they almost figured out, and there’s just a few minor details left to deal with, like making the theory of quantum gravity. To us, however, the physical world is an emergent property of meaning, that manifests our souls first, then our minds, and then we use our minds through wands to wield magic in ways that change the manifestation according to how we perceive meaning, as persons”.

Hermione was deep in thought. “They used to believe the same as we, you know. It’s just in the last few centuries that they turned it all around. Can it be that our Statute of Secrecy caused it, by removing us from their world?”

“It’s actually very likely”, Harry agreed. “Not knowing about magic and what they would call miracles, they were free to formulate theories around the most vulgar materialism, where physical world is a reality and everything else is either an emergent property, or a figment of imagination”.

“We never had that luxury”, Viktor nodded in assent. “Anyone seeing or doing conjuration or transfiguration is permanently inoculated against materialism. It’s simply not a sustainable theory”.

“Oh, you stopped playing the dumb guy”, Hermione took his hand and snickered.

“I figured I can’t win so I might as well join you”, he kissed her palm.

“What have you done to my wife?”, Harry smiled as he brought his breakfast to the table. “She’s been doing nothing but reading books on physics for the last five days. Last night she was reading equations from that guy with a cat, whatever he’s called, until it was almost morning”.

“You mean, Schrödinger equation of wave function?”, Hermione failed to contain her giggles.

“She looks like a zombie. Hair all over the place, dark circles under her eyes, and she’s talking to herself”, he laughed. “Reminds me somewhat of you when you had to get the time turner to keep up with your schedule”.

Hermione looked behind him and smiled. “Oh, here you are”.

Harry turned to see Lyra, shocked that she seemed to be back to normal. Hair perfect, dark circles under her eyes gone, eyes focused and bright. “Who are you and what have you done to Lyra?”, he smiled.

“Oh, I’m done cramming physics”, she smiled brightly. “I think I have it figured out now”.

“Oh?”, Hermione lifted an eyebrow.

Lyra poured an espresso into a glass of milk, and bit into a croissant. “It took me a while to catch up. My brain doesn’t process equations well, and by that I mean not at all. I just glaze over, so I depended on someone explaining it in plain English, or at least Greek or Latin, and what I figured out somewhat late in the process is that when some phenomenon is well understood, the translation of equations into human language is very straightforward, and explanations are clear and unambiguous. Also, I kept translating their physical concepts into magic, how something is done, what it looks like, how I could explain it in terms of thermodynamics or classical mechanics, or laws of conservation of mass and energy. Then I came to the quantum mechanics and the standard model, and I struggled, because the explanations stopped making sense in human language. Some things, like the photoelectric effect, or radioactive decay, or indeterminacy, are straightforward and easy, but most of quantum theory sounds like outright nonsense, and at first I thought it was me, because, finally, I bumped into something that’s too hard for me to understand, or at least it can’t be understood outside the equations because they are not translatable to human language. Then I saw that the muggle physicists have the same problem, and I tried to do things experimentally. I touched the magical layer with my mind and observed what happens on the physical plane, and then it clicked. I figured it all out”, she smiled like a sun.

Harry and Hermione just looked at each other. “What do you mean?”

“We truly missed each other, the muggles and the wizards. We missed their understanding of the physical world derived in absence of magic, and they missed our understanding of magic, because without it, they tried to make up all sorts of nonsense based on not knowing and statistics and question marks of all kinds, and functions that collapse as soon as you touch anything real. You see, that entire story about the quantum this or that is about their muggle world collapsing as soon as it touches the layer of magic beneath the visible, tangible world. Also, when we, wizards and witches, touch magic with our minds, it manifests in the visible world, overriding statistics, probabilities and particle relations, and having the static and inert nature of the physical world collapse, but obeying laws such as the conservation of energy, but different kind of energy – meaning, sacrifice, materiality in a sense of preserving what matters”, she was glowing with excitement. “They mapped out what matter does until it touches magic, while we mapped what magic does to the matter when we touch it, but neither of us knew the whole picture. I think we still don’t, because both of us know very little about ‘why’ things are the way they are. They know a lot about thermodynamics and how covalent bonds behave and why hydrogen bonds break down at certain temperature, while we know about the Gamp’s law of elemental transfiguration and exceptions thereto. They know how the stars are aligned into galaxies and how galaxies form galactic clusters and how there are voids between them, and Centaurs know about astrology and meaning of certain things in the sky, but neither of us know why that all is, because it comes from a deeper source. Yes, there is the physical, and it breaks down at quantum level where it touches magic, but magic is merely a layer that seems to break down at something deeper, and that deeper something is why there is love and why it matters, why there’s meaning and why things matter, and this meaning is what shines and sounds through when Hermione breaks the world when she’s stressed, and something on the other side, deeper than magic, shines through and it’s wonderful”, she finished, as her friends looked at her in absolute awe.

“Lyra, if you again tell me you’re not a proper goddess, I swear, I will tickle you on all your tickly spots, and I know all of them”, Hermione mock-threatened her sister.

Harry nodded. “I will hold her for you”.

“What’s a black hole?”, Lyra asked sheepishly while sipping her tea.

“Oh, it’s a term from astrophysics, designating an object so massive, it’s orbital velocity is the speed of light in vacuum”, Hermione explained. “Muggles did quite some advancements in philosophy of the natural world, as you would know it, having read ‘Principia’ in its original language”.

“And astrophysics is… let me guess, nature of the stars, if I translate directly from Greek?”, Lyra rubbed her chin.

“Close enough”, Hermione nodded. “Physics is the word they use for what used to be known as philosophia naturalis, or philosophy of the physical world, which was abbreviated to physics. Astrophysics is a term invented rather recently, but your library kind of doesn’t have anything since the establishment of the Statute of Secrecy, so I guess Newton’s ‘Philosophiae Naturalis Principia Mathematica’ counts as one of the most recent works of our joint civilization”.

“I mean, I know some of it – how the light breaks from white into a spectrum, and I can infer that the orbital velocity is the velocity at which speed of the object follows curvature of the Earth, or another celestial body, so that it keeps falling in perpetuity without hitting the ground. I don’t know that the light has a finite speed, or why it would be different in vacuum”, Lyra shrugged.

“So, you’re basically the greatest mind of seventeenth century science?”, Hermione giggled.

“Pretty much”, Lyra took a biscuit with apricot jam. “Would you please give me a crash course in the twentieth century physics, as they call it?”, she winked.

“Can I listen?”, Arthur’s eyes were wide.

“Sure, but keep up”, Hermione nodded.

“So, I’ll have to explain several concepts, but they rely heavily on what you already know. For instance, yes, the speed of light exists, and it’s different in vacuum because light consists of tiny luminous particles called photons, that travel straight and unimpeded in the vacuum of space, while they bounce into particles of matter when they travel in a liquid or gas, or they outright get absorbed in solid matter. The speed of light in vacuum is around 300000 km/s, and less in a medium”, Hermione looked at her to see if she’s keeping up.

“So, when you say that an object has an orbital velocity of the speed of light, this means that if you turn on a source of light on its surface, the particles of light would bend around it and keep falling in perpetuity rather than escape into space, which means no light can escape it, which explains why it’s called a black hole”, she nodded. “Things fall in, and nothing comes out, since I assume nothing is faster than light?”, she inquired, as Arthur looked at her with mouth agape.

“Correct”, Hermione smiled brilliantly.

“Does the speed of light depend on the colour of its components? For instance, is blue faster than red?”, Lyra frowned.

“No. The components differ in their specific energy, that can be measured when it is absorbed by matter, but their speed is the same. Also, and this will be weird, light particles propagate in waves, and so each photon has a specific wavelength, which is, I guess, a distance between two adjacent crests on a wave as it propagates. Red has a longer wavelength while blue has shorter, because, I guess, like a compressed spring that contains more energy”, Hermione struggled to explain.

“I figured out some of it from Newton’s ‘Opticks’”, Lyra nodded. “Light can interfere as if it were a wave, and yet it also behaves as if it were made of particles. I’m glad to hear that a definite conclusion was made later regarding that”.

It was now Hermione’s turn to stare with mouth open, but she collected herself. “Anyway, they learned other things, such as the fact that the wavelength of light stretches or compresses depending on whether the object radiating light is travelling toward you or away from you, and this is also the case with sound and other waves”.

“You mean, that’s why sounds become higher as I travel toward them fast on a broom, and lower as I travel away from them?”, Lyra perked up in realisation.

“Exactly so”, Hermione confirmed. “It’s called the Doppler effect”.

“How does this relate to astrophysics?”, Lyra asked.

“Well, most directly, it allows us to know whether some star is moving towards us or away from us”, Hermione answered.

“Oh, I get it. The light it produces would shift towards red or blue. If it is reddish, it would mean that it is moving away from us, and if it is bluish, it would mean it’s moving towards us. But how can you tell whether it’s a star that travels away from us, or it’s just a star of a naturally reddish colour?”, Lyra wanted to know.

Hermione looked at her with complete amazement, thinking that’s probably how Newton would look at Archimedes or Aristotle if they got the chance to talk. “Now, there’s a thing. The stars have types, and they have a life cycle, and there’s a specific characteristic they tend to have depending on their mass and their place in their lifecycle. If you know that a star is naturally yellow, and you perceive it as reddish, it means its spectrum is shifted”.

Lyra nodded. “I get it, but I guess you would have to know first in order to extrapolate the transformation”.

“Exactly, which is why there’s lots of assumptions in astrophysics, and occasionally it gets corrected, when they realise that something isn’t a very big red-shifted object very far away, but a much smaller, naturally red object much closer”, Hermione nodded.

“I get it”, Lyra nodded in return. “What are stars, actually?”

“They are in essence the same category of objects as our Sun. They are big, very massive, and they produce light by fusing light atoms of matter into heavier ones due to the extreme pressure in their cores”.

“There are many things I don’t understand there, for instance how that actually works, why atoms need to be pressed together and why they produce light when they are joined together”, Lyra frowned.

“Well, what you need to understand is that atoms don’t actually exist, in the way Democritus imagined them. Sure, matter consists of smaller particles, but those particles consist of even smaller particles. Every atom consists of a nucleus and a swarm of electrons, that have a negative electric charge. The nucleus consists of protons and neutrons that are all bound together. Protons and neutrons have about the same mass, and all the mass of an atom is contained in its nucleus. Protons differ from the neutrons in that they have a positive electric charge. There are forces in the atom that keep the electrons attracted to the core at one distance, and repelled when they come closer”, Hermione struggled to explain.

Lyra gave it a thought. “What is an electric charge?”

Hermione started fidgeting and pulling at her hair as she tried to figure out an explanation. “The ancient Greeks discovered electric charge when they were rubbing amber on wool and it would produce glowing sparks”.

“Ah, so that’s why those negatively charged particles are called elektron, which means amber”, Lyra perked up.

“Exactly. Such sparks happen when there’s a difference of electrically charged particles in different objects, and when they equalize with a spark. Lightning is merely a very big spark. The muggles made all sorts of discoveries regarding electricity, like the way electricity can travel through metal and produce magnetism. You know what that is, right?”, Hermione was curious.

“Yes, certain stones tend to point in a north-south direction and attach themselves to iron”, Lyra nodded.

“When electric charge travels through a metal wire, it produces the same effect, and it’s called electromagnetism. Similarly, as Earth spins, making a full circle every day, some of its molten interior layers spin at different speed due to drag, and it creates a magnetic field around the entire Earth, which manifests as magnetic poles, which attract the magnets to themselves and create the phenomenon you are familiar with”, Hermione confirmed.

Lyra thought about it. “I guess different kinds of matter have different structure, which is why it works for metal and not for wood or dirt. I guess those electrons around a nucleus in an atom, that are attracted at one distance and repelled at another, can also be lost, or exchanged between atoms, or expelled to create an electric charge”.

Hermione was even more stunned, but tried to continue. “Very much so. All the matter we normally see is made when two atoms share electrons between them. Those are called chemical bonds, and they combine atoms of different elemental substances, also called elements, into chemical compounds, such as water or salt”, she nodded.

“And I guess the atoms can have more or less energy – if something is cold, it would have less energy and the atoms would come closer together and form a solid, but if you heat it up, it would form a liquid and then a gas, as the atoms get far enough apart from the excess of energy that they fly off”, Lyra offered.

Hermione’s eyes went wide. “Exactly so. And if you compact the atoms together by force, introducing outside pressure, they will bleed the excess energy until they become cold enough to naturally be able to function at such proximity without repelling each other”.

“And if you apply enough pressure, the cores of different atoms, that are normally separated by a layer of electrons, will bump into each other and form a different kind of atom, with all their combined protons and neutrons forming a new nucleus?”, Lyra inquired, to Hermione’s amazement. Arthur, on the other hand, lost them very long ago and just looked confused.

“That’s exactly right”, Hermione confirmed. “And in some cases, when the atoms are light because they contain only one or two protons, this will produce an excess of energy as some of the bonds within the nucleus release in form of light, which is what happens in the stars. On the other hand, when very heavy atoms are broken apart, which can also happen, the excess of energy is released and two lighter atoms are produced”.

“So, I guess depending on how heavy a star is, it will produce slightly different light. Also, as it keeps spending the light atoms and producing the heavy ones, it will eventually run out of light atoms and this is probably what you meant as stars aging through their life cycle”, Lyra offered.

“This is exactly right”, Hermione confirmed, with profound amazement. “And when a star grows very old, and runs out of all atoms that are light enough to produce an excess of energy in a process of nuclear fusion, the balance of pressure and gravity is disturbed because production of light no longer creates an outward pressure and all the matter collapses inwards, creating an incredibly strong explosion”.

“Wait, are those the stellae novae the ancients wrote about? When a new star appears, or becomes much brighter for a while, only to fade away later?”, Lyra remembered.

“It is exactly so, and this is why in astrophysics, those are indeed called stellae novae, or just novae. There’s also a category of “super nova”, which is a particularly large explosion that happens with stars much massive than our Sun, because the energies involved are much greater. Also, when those extreme energies and masses are involved, there gets to be a remnant of the exploding star, that is so dense, that all the mass collapses together with such force, that the protons lose their electric charge and transform into neutrons, and the entire object consists of neutrons tightly pressing together, with the entire thing rotating as fast as thousands of times per second”.

“Oh, so that’s what you meant by a ‘neutron star’. It’s a remnant of a dying star that spins very quickly and is made of only neutrons”, Lyra nodded.

“Exactly. And this object is very small and incredibly dense, and this creates incredibly sudden, violent rises in gravity, which means that if you were to fall into it, it would pull your feet so much stronger than it would pull your head, that it would exceed the attractive forces between the atoms of your body and draw you out into a string of liquid. This is actually called ‘spaghettification’ in astrophysics. When we add the effects like frame-dragging caused by the extremely fast spin of the neutron star and a black hole, you get the effect where the spaghetti-ribbon consisting of extremely overheated atoms of the unfortunate thing falling in start wrapping around the massive object as a glowing ring”, Hermione explained.

“Which is what you did to those unfortunate idiots”, Lyra grinned.

“Exactly”, Hermione smiled.

“And I guess the sole difference between a neutron star and a black hole is in its gravity, because a black hole is so massive that even the light can’t escape it, while a neutron star is close enough but not there yet”, Lyra raised an eyebrow.

“Exactly so”, Hermione nodded. “The distance from the black hole at which the escape velocity is the speed of light is called the ‘event horizon’, because it’s the point after which nothing can escape the black hole to tell the tale of what’s inside”.

Lyra nodded. “I think I got it. Can you please get me some muggle books about that, so that I can learn it in more detail? It sounds very interesting, and I’m completely ignorant of it all, obviously”.

“You may be ignorant, but this was the most impressive feat of raw intelligence that I ever witnessed in my entire life, and if I didn’t already worship you as my personal deity, I’d start now”, Hermione looked at her sister adoringly.

“Are the two of you even human?”, Arthur managed to say. “Because I don’t think so”.

“Oh, I’m just a very smart human”, Hermione winked. “I still don’t know what she is”, she added.

“Hermione, you held my hand and checked my cervix for dilation when I was giving birth. You know exactly how human I am”, Lyra smiled.

“True, but you just may be some deity taking human form”, Hermione pointed out. “It’s actually the most parsimonious explanation”, she grinned as her sister hid her head under the sweater and whined.