The star Tiamat was dying.
She was a blue-white supergiant, massing some fifty octillion tonnes -- twenty-five times that of even a bright yellow main-sequence star. The immense bulk of matter stretched, in the time of her exuberant youth, over twenty million kilometers from surface to antipodal surface, where plasma roiled in the inconceivable radiance produced by 26 thousand degrees absolute, emitting a storm of actnic radiation by comparison with which a more normal sun would have been but a dim red ember. She would have looked blue-white to organic eyes, because the upper ends of the optical spectrum would have been the principal part of her output which organs formed of flesh and blood would have been able to detect.
Such would have been her normal appearance; such the mien she had worn during most of the three and a quarter million years she had lived since she had first flared to life in the depths of a dense nebula, her lusty infant birth-cry flashing out to clear the veils surrounding her with the immense pressure of her stellar wind. Three and a quarter million years -- an immense amount of time in the lifespan of an organic mortal -- but barely a day on the scale of most of the mortals made of hydrogen and helium which lived by burning their own substance in their fusion fires, which the organics named "stars."
For three and a quarter million years, Tiamat had blazed brightly in the firmament of the Universe. She had been one of the greatest stars of her galaxy -- so brilliant that she was visible from the closest other galaxies, and would in time be seen from other galactic clusters, when her light had time to reach them.
But by then, of course, she would be long-dead.
Big and bright, she was doomed to suffer the fate of all big and bright members of her kind, and run through her thermonuclear fuel at a ruinous pace. Her torrid inner fires, fed by a gravity many times greater than that of any main sequence star, had converted immense quantities of hydrogen to helium every second, every year, every millennium.
As the millennia wore on, Tiamat fused all the hydrogen she had to helium. When the hydrogen ran out, she shrank, compacted under the force of her own gravity, until the temperature at her core rose to an astonishing two hundred million degrees absolute. Under such extreme conditions, the triple-alpha process began fusing helium into carbon and oxygen. And Tiamat burned on.
But her time was running out. The helium began to be exhausted; the fuson fires sputtered within her heart. The end of helium-burning was fast-approaching; when it ensued, this would not be the immediate end of her life, but it would signal her inevitable death, in but a few thousand more years.
All life perceives time in terms of its own vital cycles and span. A typical star, which lives for billions of years, experiences one billion years as we might a decade or two; a hundred million years as a year a few tens of thousands of years as a day. To such a beng, a long-lived organic civilization might last for but a few hours.
To Tiamat, who would live but 3200 of our millennia, her life passed at a far more rapid pace than did that of lesser stars. Her thermmonuclear heart beat hot and fast, her life passed in a frenzy of fusion fire. By the standards of smaller, more sedate suns, she would be for but a season, barely seeing a fraction of an orbit around the center of her Galaxy. Her life would be brilliant, but brief.
She was not alone in this. The rich nebular cloud which had spawned Tiamat had also birthed a score of siblings: some of them lesser supergiants; most of them hot, bright stars, who had been nourished by the density waves of Tiamat's own ignition. Together, the twenty-one young, doomed stars formed a little cluster, only a dozen light-years across at its longest axis.
Within, all were friends. The stars of Tiamat's cluster warbled and hissed and popped at each other in their unceasing electromagnetic song; even at the frantically-accelerated paces of their superheated lives, the signal-to-response lag from one end of the cluster to the furthest end and back was but a quarter-century -- to them, the equivalent of half a minute or so. They were, by stellar standards, both physically and emotionally close to one another.
Closest of all to Tiamat -- in fact, describing a braided orbit around each other as a distant binary -- was the smaller supergiant Barba. Their orbits varied, as one or the other was tugged by the other stars of their small cluster, but never were they more than a hundredth of a light-year apart. By stellar standards, they were very near neighbors indeed, and they chattered to one another constantly -- though Tiamat mostly talked, while Barba worshipfully listened to her larger sibling. Their friendship was the most precious thing in both their lives.
This was true for Barba, despite the fact that it doomed her to a lessened lifespan, something of which they were both well aware. For Tiamat and Barba, while young, were neither foolish nor wholly innocent. They had witnessed the lives of the stars for many millions of light-years around them, for a length of time exceeding the lifespan of most sapient organic species. They had moreover conversed with many longer-lived stars, including the little red dwarfs, whose fires burn so dimly and slowly that the eldest of them still are children, for our Universe has not yet lived long enough to greatly age them.
So they both well knew what happens to a star caught within fractions of a light-year of a type II supernova, especially when that star is herself big and bright and hot and but indifferently stable, forever teetering on the edge of her own supernova. They heard the stories from older stars; saw the warnings written in intense flares of light, briefly outshining whole galaxies; felt the truth of it within their very hearts, where the immense forces of Fusion and Gravity wrestled within them, their contest keeping the critical balance between explosion and implosion, flare and collapse, at whose boundaries lay the life of any star.
Massing a bit less than half as much as Tiamat, some twenty-four octillion tonnes, Barba on her own might have shined for twenty million years. In close company with Tiamat, though, she would perish when Tiamat did, for the immense surge of energy and infalling of matter from her companion would imbalance her own life, and trigger the explosion of Barba's own core.
They had been born and lived together; they would die together. These were their dooms; dooms shared in lesser degree by their siblings. For a close cluster of hot bright stars is inherently unstable: the death of the biggest may trigger a chain reaction of supernovae and nova flares which destroy many of them, and greatly shorten the lives of the survivors.
Such is the price of being big and brilliant, and keeping company with the big and brilliant, in the world of the stars.
The time came when Tiamat knew that her last days were upon her. For her helium, which had long since sank to her core in a shell, displacing her remaining hydrogen, had been itself been slowly squeezed out of her heart by the buildup of the carbon and oxygen which came from the triple alpha process.
Twenty million degrees absolute, though very hot even on the scale of a stellar core, is not hot enough to fuse carbon. So her central fires flickered out.
In that moment, Gravity gained in the endless struggle within Tiamat's core. Tiamat gasped and shrank, her core imploding, compacting from its already great density of two thousand times that of liquid water to an absolutely astounding million times that amount; an increase of five hunded times its previous value.
So compressed, not even the more massive nuclei of carbon atoms could keep their integrity. At Tiamat's core, carbon began to fuse: becoming neon, sodium, magnesium and aluminium.
Tiamat knew what this meant. A star could not live long burning anything but hydrogen; or in a pinch helium. The new fires within her had countered her core collapse for the moment; the moment would not last long by stellar standards. She now had but a matter of millennia to live -- at best some days, by her own temporal perceptions.
"Tiamat!" The worried cry came from Barba, who had felt the neutrino pulse from her boon companion, and also understood its meaning. "Are you all right?"
"It's ... what we knew would happen," Tiamat told her. "I'm burning my carbon now. A ... perfectly natural process. Nothing to worry about. It unsettled me for a moment. But just a moment. I'm perfectly chipper again."
Tiamat's concsciousness was an intricate neural net of electromagnetic currents powered by her heart and running through her immense bulk. From the core, the webwork field lines and computative nodes extended out through her radiative and convective zones, through the photosphere and chromosphere, to finally trail off into a vast array of whisker-like filaments in her rarefied corona. Within were many specialized organs, some analogous to those in organic mortal life, and some very alien in purpose.
The stability of this neural net had of course been shaken by the immense change which had happened within Tiamat's core, but the dynamically-regenerating pattern which was Tiamat the person had survived, mostly unchanged. The substrate of matter and energy which was Tiamat the star supported the magnetic fields which organized into Tiamat the person, but they were not the same thing. Tiamat, now burning carbon instead of helium, or the hydrogen of her prime, was still Tiamat.
"I ... I'm ... I'm glad," said Barba. "That you're still yourself."
"One must keep one's grace under pressure, darling," replied Tiamat, doing the equivalent within the shared conceptual space of their conversation of smiling warmly at her lifelong friend. "Whether that pressure be compressive or expansive in nature." Then her expression sobered. "I will, of course, not be able to keep myself together for too much longer, and you know that my end will be rather destructively spectacular."
"Yes," said Barba. "I know. And I've been thinking about that."
"Are you at last going to widen your orbit?" asked Tiamat. "You really should. My final flare will shorten your life in any case; there's not enough time for you to get far enough away from me to totally avoid it. But, well, inverse-square. Every doubling of distance will quarter the damage to you ... let you go on longer."
"No," said Barba firmly. She seemed to gather up her courage. "Tiamat, I want to spiral inward. When you go, I want to go as well. I ... I want us to mingle."
The life cycle of the stars is not the life cycle of most vertebrates. They reproduce by exploding, spraying their fusion-processed substance into the void. This creates nebular clouds, from which new stars form.
Only the larger ones -- ones massing more than two and three quarters octillion tonnes -- reproduce. And only those massing more than around sixteen octillion tonnes, stars such as Tiamat and Barba, can spawn stars with enough metallicity to form complex planetary systems around them.
Stars can love one another. Binary stars can even caress one another with filaments of magnetic fields; enrich one another with matter siphoned or even shared from their surfaces. But to do what our kind of life does, and share the bulk of their equivalent of genetic information to make new stars from both their masses -- they must die, close together in spacetime.
This is what Barba was proposing, to her lifelong beloved friend.
"No!" cried Tiamat, her tone anguished. "My dearest, you simply can't! If you do that, you'll die within instants of me."
It would actually take many hours, even days of our sort of time for Barba to explode after Tiamat did, but on their timescale this was almost simultaneous.
"I know," said Barba. "But I ... don't want to outlive you. I love you. I have always loved you. You know that. You've always known that."
"I do," replied Tiamat. "And ... I feel the same. As you have always known."
"Then we shall die together," said Barba. "And our selves will join, to make a new cluster."
"Yes," agreed Tiamat, "though I wish you might live. But I shall not deny you your last wish, my dearest one. And ... a shamefully selfish part of my self is gladdened by the thought that at the end ... the very end ... we shall be closer together.
The naive astronomers of nascent Type I planetary civilizations, limited as they are by their assumptions that they may be the only intelligent life in the Universe, and that in any case "life" must be based in molecular reactions, imagine the stars to be inanimate objects, whose motions are wholly at the mercy of Newtonian and Einsteinian gravity. It is true that, by the standards of little organic beings, stars have immense inertia and can move their vast bulks but very slowly.
But they are capable of voluntary motion, a fact which would astound those primitive astronomers.
As Barba and Tiamat proceded to demonstrate.
Each of them adjusted the flow of plasma by means of their many and diverse organs, making great conical rifts in their photospheres; funnels which led into their deeper, hotter layers. These funnels were anchored to their whole immense forms, by means of complex three-dimensional networks of enhanced electromagnetic fields. Each of them slightly ramped up the fusion at their cores beneath them, increasing the exterior pressures at these points. They squeezed, and hot plasma from their interiors jetted out the funnels in truly immense stellar flares.
Propelled by the plasma rockets they had ignited, Tiamat and Barba began to -- necessarily very slowly, to avoid prematuringly exploding -- spiral closer to each other.
The two supergiants approached their final union.
Well... I never thought I would be intrigued by a romance between stars. FAVORED AND ANTICIPATING!
Very interesting and original! MOAR pls~<3
This astrophysicist highly approves. A few notes:
1. It is highly unlikely for a type II supernova to disrupt its companion. Even if the energy of the explosion is, say, 2 to 3 times the energy required to unbind the star, its companion will only receive a small fraction of that energy; most of it is quickly consumed to heat the debris and is then radiated away. The companion star might lose its outer layers, but its core (and probably its lifetime) would be mostly unaffected.
2. 1.4 solar masses (the Chandrasekhar mass) is the upper mass limit of a white dwarf, the core of a dying sun-like star; accretion beyond this limit causes a type 1a supernova. Stars between 0.3 - 8 solar masses will become red giants and, eventually, white dwarfs.
3. A nova is a non-destructive phenomenon in which a white dwarf accretes mass from a swollen companion and builds up a layer of hydrogen on its surface, which spontaneously fuses in a deflagration that does not disrupt the white dwarf. This cycle can repeat many times, and is known as a cataclysmic variable.
Other than that, major props for the level of detail and scientific accuracy, including the appropriate relation between mass and lifetime. I really love this concept of
Fusion and Gravityproto Rarity and Spike spending a lifetime as sentient stars, and I can't wait to see where this goes.(BTW, if you want or need any clarification on space stuff, I'm actually a 2nd-year astrophysics grad student, and I'd be happy to help. If not, that's cool too, as long as the writing is good -- which yours always is.)
This is incredibly adorable in a flaming-balls-of-doom sort of way, and I can't wait to see what you do with this.
8601045
I am not surprised that I got some of the astrophysics wrong.
Actually, Tiamat and Barba contain Sparks that will become part of Rarity and Spike. Fusion and Gravity and Dissonance have yet to make (personal, rather than physical) appearances.
8601068
Ohhh, Barba = Spike. Barbs, spikes. I get it.
8601045
My guess is that this is assuming there is an as-yet-undiscovered way to use neutrinos drastically more efficiently than their apparent behavior. So what Tiamat will do is unleash a tremendous high-energy neutrino flux that will result in splitting neutrons in nuclei in Barba's core into protons and electrons. Since the nuclei are now so neutron-starved that protons boil off, you now suddenly get a tremendous increase in hydrogen in the core. After Tiamat's core becomes a black hole and stops flooding neutrinos, Barba's hydrogen cools enough to induce extremely rapid fusion, driving her to explode prematurely.
If we want to explain "magic" in Equestria and in EqG's pseudo-Earth, the energy must come from somewhere, and the neutrino flux seems like a least-implausible source if some mechanism exists to massively enhance their effective cross-sections.
Of course Rarity's soul would incarnate as a supergiant. It would settle for absolutely nothing less as a literal star. Aside from the intergalactic visibility, seeding a planetary system with her corpse would/will be the ultimate artistic statement... at least until she can perform such works without self-detonating. (Plus, the fact that Rarity can still find herself a social circle with which to gossip even as a naturally occurring fusion reactor is too perfect for words.)
Definitely looking forward to seeing the trio meet Tiamat as she and Barba pass on. I can only imagine what the other Bearers-to-be were in their previous incarnations, especially given all the different varieties of life as we don't know it.
8601341
If I'm reading Jordan's intentions right, she will, in a sense, be the mother of dragons. And of every other life form on Earth.
when I entered this I was kind of expecting this to be the star magically transformed into Equestria's sun, which being controlled by a living being and orbiting a planet is necessarily different than other stars
I imagine all five of Queen Tiamat's heads laughing at learning that Rarity was previous incarnated as a star who shared her name.
Then again, it could be that Queen Tiamat took the name herself, while she was still designing the dragon species (back when she thought intelligent was a waste of bio-mass), impressed at this star. Though it's interesting she snatched Barba's soul rather then Tiamat the Star's to be one of her children.
8601401
Here's the problem though: even if the nuclei and neutrons in Barba's core were all dissociated back into hydrogen, and then fused at the temperature and pressure of the triple-alpha process, that wouldn't be enough energy to unbind the star. As another example, consider the helium flash in red giant stars: the core is entirely composed of electron-degenerate helium, so when it ignites, the rate of energy release is, for a split second, similar to that of a type 1a supernova. The star does not unbind and explode because the pressure and gravity of the outer layers absorbs all that energy. The core would shine incredibly bright for a brief moment, then expand and cool until the star returned to hydrostatic equilibrium, and hydrogen fusion would proceed as normal. Remember, fusion rates have a very steep dependence on temperature, so the core is very quick to achieve equilibrium.
I agree that neutrinos are the least-implausible source of excess energy in this scenario, but there is one thing you've neglected to account for: the upper mass limit of neutrinos is << 1 eV, while the binding energy of a helium-4 nucleus is 28.3 MeV. Even with ultra-relativistic neutrinos, it would be nearly impossible for even one helium nucleus to unbind into hydrogen, let alone the entire core. There is a process by which nuclei in a massive star's core unbind into helium, but that occurs in an iron core as the precursor to a type II supernova, and is driven by high-energy gamma rays; this is known as photodisintegration.
Now, all that being said, this IS sci-fi, and very good sci-fi at that, so I'm willing to give it a pass. I just really like debating and nitpicking details, especially ones related to my field of study. I hope we can have more discussions like this in the future -- you really made me think about all this and look stuff up, and the best kind of debate is one in which both sides learn something.
I look forward to more thought-provoking discussions like this one as this story progresses. Until then, have a mustache.
A part of me is slightly disappointed that Tiamat’s partner wasn’t named Abzu.
Apart from that though, this is a really fantastic and creative concept and I’m definitely looking forward to seeing where it goes.
We are forged from the hearts of dead stars
8606465
Exactly. Both generally, and in a sense very specifically important to this tale.
Okay, this is different. This is the kind of Glorious Weirdness I wish more SF was composed of.
And talking about your list of stories about sapient stars, did you ever read a Golden Age tale by, I think, Jack Williamson? Born of the Sun was the title if I remember right. It was sort-of like this, but much 'pulpier'.
8620084
Yes. Jack Williamson did more than one story about sapient stars, too. His Reefs of Space series included that concept.
The earliest example of sapient stars of which I know dates back to Stapledon, but he definitely inspired other writers.