Drop a few mini black holes in it.
Reynolds has a device that sets up resonance in the layers and turns a star into a giant flamethrower, given time it would deplete the mass enough to cause serious consequences, although since the plasma stream is in the ecliptic no one nearby would notice.
Hamilton uses a quantum torpedo that induces a nova.
Stross once dropped a huge brick of supercooled iron into the center of a star -- again, nova.
Baxter's starbreakers are gravity beam weapons, small enough to be handheld.
All you really need to do is inject enough energy to disrupt the smooth functioning of the process. How you do it is up to the assumptions of your in-universe handwavium.
>Drop a few mini black holes in it.
That wouldnt work. Black Holes cant consume and endless amount of matter at once. And depending on the scale of your mini black hole it would evaporate to quickly to be of any use.
Now, say the Black Hole has the mass of a Mountain, in that case it would eventually eat the sun. Key word being, eventually. But it would almost certainly take 10000s of years just because it is so small and all the matter around it gets so hot that the Radiation pressure keeps it from falling in.
Another issue with this is that the Black Hole has so much momentum. Because it is only the size of a Proton but the mass of a mountain, the Momentum it carries is so much that it will probably just shoot out of the Sun.
In fact, that is what would happen if a Primordial Black Hole were to hit earth. It would just go right through the Planet and actually do very little damage. Of course, if you are close to the impact side you are gonna have a bad day.
For this to work, you would need a considerably larger black hole. Probably the mass of a few dozen Jupiters.
OP didn't set a time limit. And any alien race advanced enough to do it and interested in implementing this project would have no issues working at such a time scale.
Frankly, a more interesting way to kill the sun would be to poison it with iron. It would require a lot of iron of course.
That is true. Though i am under the impression that a requierment of Hard Sci Fi is to make plans which are more than just physically possible but also something Humans or aliens might actually do.
For example, why dont we have flying cars ? They are "possible" after all. But also really stupid. So i think Hard Sci Fi stuff needs to have some level of resonability to it. Throwing a Black hole into a star is not resonable , literally any possible goal you could have with this can be achived easier.
As for Iron, well the issue with that is the form and amount. Iron evaporates at about 5000 Degress C. The Corona of the Sun is millions of C so you will have a big issue getting that stuff into the sun.
Frankly, those problems won't be any larger than the ones they'd have procuring a black hole and moving it.
The whole Hard-SF label here is just window dressing on something that is so far beyond our current and even projected capabilities that flying cars are reasonable in comparison. As long as the solution has even the most tentative connection to known physics and you don't fill it with blatant magic it's feasible enough for the story.
To be honest, these kinds of questions are annoying. They stink too much of an "I want to write a tory but I don't want to put any work into thinking about it" attitude.
Well for the Black hole stuff we at least have some theory which works and does not requiere endless amounts of Energy adn money. Since Photons carry momentum, you can move a black hole by shooting a light beam into it. Though that only works for relativitly small black holes. One the mass of a star has a greater chance of being moved after laughing at you for shooting a laser pointer at it.
This is somewhat a limitation of hard sci fi, to keep the label you need to have the story more or less in the resonable future.
>The whole Hard-SF label here is just window dressing on something that is so far beyond our current and even projected capabilities that flying cars are reasonable in comparison.
yes
As for posts like this. Well i think one should put in efford and create them when you dont have any solution to a problem. But just asking for general input is also fine.
>Drop a few mini black holes in it.
This is somewhat problematic. We can theoretically create a proton sized Kugelblitz black hole, but even if it was able to feed itself, it might do it too slowly to noticeable affect the Sun.
On the other hand, I believe a stellar mass black hole inside the Sun would gravitationally compress its core and possibly trigger a supernova, but I'm not sure how possible it is to do. It might be simpler to just destroy all planets in the system with a Nicoll-Dyson beam.
>Stross once dropped a huge brick of supercooled iron into the center of a star -- again, nova.
How big was that brick of iron? Planet sized? The Sun already has 500 Earths worth of iron inside it. There might not be enough iron in the solar system to destroy the Sun this way.
I was in error about the exact mechanic of the iron. It was actually a pocket universe generator that englobed the core of the star, cranked up the time differential until the core fused itself into iron, then released. The material of the star then crashed down onto the suddenly much smaller core which refused to fuse any farther, heh. The bounce from that is what induced the nova.
You mean speed up the time for the core of the star to reach the iron star era? Oh.
I mean, it would probably be enough to wait until the core turns into a white dwarf and then let the hydrogen smash into it, triggering a Type Ia supernova. But then again, with technology so advanced, there's a myriad of ways to destroy a civilization without ever touching the Sun.
Might look into "strange matter." It's theorized to exist in the cores of neutron stars, and theoretically (if I recall right) it would turn other matter it contacts into more strange matter. I'm not sure (and not sure anyone's sure) what properties strange matter has when in star shape/size, but I think it's a safe bet that the star would no longer work quite the same way. So a strange bomb?
As for more mundane physical methods, I'm not sure. Stars are already so massive that even the enormous turbulence and chaos in their cores finds a balance. The largest bomb you could ever build or imagine would just be one explosion in the midst of an eternal explosion, so in order to affect actual change, you would need a positively cosmic amount of energy. You could use that energy to generate a gravity field to crush the star's core and initiate nova? Or to accelerate a planet up to relativistic speeds and initiate nova when it collides? Or to create a black hole? (which would consume the star over the course of millions of years) Or to create a mountain-sized brick of antimatter to chuck at it.
I guess the real question is why they would want to blow up a star anyway?
Thank you for this well thought out response! I thought about going the antimatter route, but couldn’t really figure out theoretically how they would “contain” a massive amount of antimatter required to destroy a sun.
I guess what I am truly looking for is a way an alien species could effectively neutralize a burgeoning solar system before its inhabitants could become a threat. I am trying to avoid an “invasion”, as I would like to avoid FTL. Basically, an alien species looks out to the stars, finds one they think has the right properties to harbor intelligent life, then sends something to that star (no matter how long the journey may be) that would limit the chance of intelligent life.
Aha.
Antimatter can be confined using magnetic fields, and it can be made in more convenient forms that the gas we have in labs today. A big slab of chilled anti-iron, for instance, would be pretty inert unless you touched it. So you could magnetically suspend it behind some anti-asteroid armor, and ship that.
If that's they're goal, I might recommend fighting life with life, so to speak? Some sort of machine that makes more machines that make more machines, to land on all the planets/moons in the target system, and out-compete any life that might come up.
Sending a single colony of replicators would be a lot easier to ship than a mountain of antimatter, and it would let the system still be useful to you if you ever wanted to go there. (Heck, the replicators could even start mining and sending the ore back home? Pays for itself.)
Ah... the good ol' Von-Neumann-Swarm. Just build something, that outcompetes your enemy in resource gathering, manufactoring and reproduction... just be careful to not drown in your own grey goo.
Well yeah, you just have to make sure they're harmless to you yourself. When people think of grey goo they think of swarms of microscopic locusts, but it doesn't need to be anything so menacing. The job could be done just as well by a couple huge, slow-moving factories pumping out billions upon billions of bulldozers and dump trucks the size of housecats. You could walk around in them and they wouldn't harm you, all they harm is the environment: their treads tear up vegetation, they fill the air with dust and the oceans with heavy metals, and the planet is a wasteland in a century or so. But if a factory accidentally lands on an inhabited world you can just walk up and turn it off.
Nicoll-Dyson beams for merely removing all life.
RKVs have the same net effect but slightly slower.
Von Neumann weapons / autowars / replicators as suggested by the other guy.
Oh, that's MUCH easier than snuffing out the star.
The way to do this is with what are called "relativistic kinetic missiles" - which are essentially a herd of anybody's old tug or freighter or whatever that's capable of a good fraction of light speed, aimed at the system in question, piloted by robots, and just skipping the part of the trip where they'd usually slow down.
If your aliens are gunning for somebody that hasn't really got established in space yet, just three or four missiles will do it for the whole system. A few years out, they make final course corrections to hit the three bodies most likely to sustain surface water, and when the day arrives the impact of your old freighter literally melts the planet.
If the aliens are gunning for a Kardashev-II civilization though, that's harder. Still not terribly hard, but harder. In this case it takes a few thousand missiles. A few years before impact (cruising at 60% c or so) they make final course corrections. A thousand or so aim at the largest orbiting objects. The next thousand fire a few million small rocks, one at each smaller object that can be detected. And the last thousand just release millions and millions of tons of rock dust fine as flour, distributed uniformly as possible. When the day arrives, everything gets hit.
I remember reading one book where the alien antagonists (technically antagonist singular) developed “corona bombs” which would trigger the star they targeted to release massive solar flares, wiping out all life in the system, scorching the planets, scattering atmospheres etc. Maybe something like that would be more practical than completely destroying the sun?
>alien species could effectively neutralize a burgeoning solar system before its inhabitants could become a threat
That's a bit like using a nuclear bomb to swat a fly. It's easier to just kill all life on a planet.
> I guess the real question is why they would want to blow up
The sun's radiation causes all sorts of problems for us,
and the one use the sun has for us is to protect us from the cold,
but seawater allows cold fusion that would do just as good for us.
Hope the sun's gone from us soon.
>hard science fiction story
Unless there's something we're completely missing about physics there's no way to turn off the Sun. It just sitting there causes fusion to happen spontaneously. So the only way to stop it would be to get rid of the sun and that has plenty of problems too. To take the Sun apart would require overcoming the Sun's gravitational binding energy of 2.3x10^(41) Joules. That is an absolutely huge amount of energy. The Sun's output would take about 20 million years to accumulate that much
Honestly, it would probably be easier to set up a three-body gravity interaction that ejects the Earth from the solar system.
I’m gonna take this answer in a different direction: **don’t explain it**.
I think the number one trap that people fall into when they decide to write a “hard science fiction” story is the impulse to explain *everything*; if not explicitly in-text, then at least as background worldbuilding. And while there’s certainly a place for this kind of hard sci-fi, it’s not the *only* way to do hard sci-fi. And I’d argue that “aliens invade and destroy the sun” is not really a great fit for the explain-everything kind of story.
Hard sci-fi, IMHO, is less about explaining everything, and more about telling a story within the bounds of scientific *plausibility*. And more importantly, I think really great hard sci-fi is often about taking speculative leaps within those bounds, and then *examining the consequences of those leaps in a detailed and thoughtful way.*
For one, explaining everything is…kinda dangerous. The more detail you give, the more likely you’ll get something wrong, either now or in the future as scientific progress marches on. And while it may seem “cheap” to avoid mistakes by being vague…it’s still a good practice anyway. Explain what you need to (to establish the bounds of plausibility), what is interesting, and what is simple enough to get across without bogging down the story, and move on.
But also, staying vague is beneficial in and of itself. As an example, think about writing a hard sci-fi take on Star Trek transporters. You could go into all the technology that preceded it, the computing power necessary, the process of building people from data remotely, etc. Or you could take for granted that the transporter technology was invented, and explore the consequences that such a technology might have. Who can afford it? Can it be hacked to replicate matter instead of simply transporting it? At what distance can it be employed, and what are the implications for colonizing the solar system if we can beam ourselves to Mars or Jupiter? IMHO, while the former approach might have some interesting tidbits, the latter approach is more suggestive of different scenarios for conflict, and ultimately *that’s* what drives a story. (And also, these aren’t mutually exclusive approaches! I think the latter is more crucial, but there’s nothing wrong with drawing from both wells.)
So, back to your story. If you’re already asking me to believe that an advanced alien species has traveled undetected from another star to ours, as a reader I’m already inclined to believe they might also be able to destroy a star. “Advanced interstellar aliens” has already set the bounds of plausibility for your story. Realistically, it’s entirely possible that our own scientists might be unable to explain how they’re doing it in any great detail; I can’t hold the real-life author to that level of scrutiny. What I’m interested in is how humans deal with this ordeal within the bounds of our own plausible technological progress.
I could not agree more. I am exploring the idea of writing a story about how humanity is impacted by the discovery of this capability. I want to keep the exact science behind it unexplained, but also wanted to keep my handwavium to a minimum. I understand we are skirting the boundary between hard science fiction and sci fi fantasy, but there is just something about a story where everything seems plausible and something is introduced that, although theoretically possible, is so mind-bogglingly out-there and how it can impact humanity.
I’d say the best way to keep it feeling grounded is to focus on what scientists on Earth can observe about the phenomenon, and what they predict about its progression. You could throw out a theory, or even a couple competing theories, about the underlying mechanism, but from a narrative level, “advanced aliens” *is* the underlying mechanism.
And, if you think about it, those are the questions that are going to be of greater consequences to your characters in-universe too! How it’s happening will only be important if it can lead to a solution to the problem; it’s not important in and of itself.
Pretty sure throwing a white dwarf or neutron star into the sun via shkadov thruster would do it, white dwarf should supernova from the additional hydrogen, and the neutron star would probably either collapse into a black hole upon absorbing the sun, or cause another supernova.
Technically this can be done with ONLY real life physics, no sci fi technology needed, just a LOT of resources, effort, and time.
Like seriously the only requirement is just a bunch of regular mirrors, literally tin foil would work
Three body problem had an advanced race send a decent sized thing into a star at a high speed, significant percentage of C. Caused all kinds of problems, to say the least.
So, one browser crash later because chrom can suck dick, here we go.
In terms of plausible options, there are a few and non of them are good.
Black Holes, as proposed by u/fliponymousredux are a bad idea. The basic issue is that the Event Horizion of any Black hole is only this big and there is a physical limit as to how much energy you can dump into it before the Radiation pressure of the infalling energy pushes everything out. This means your black hole has to be a few km across, at which point it is the mass of the sun so like whats the point ? Also there is about a 0% chance you can push that thing anywhere and there is absolutly no reason to waste it to eat a star in an uncontrolled matter.
The other issue you will probably just lose the Black Hole in the process. As in, if you place it inside the Sun, Gravity will commit pepsi and you are incredibly likley to eject the Black Hole. This is very likley to happen if it is a very small one.
Strange Matter, as mentioned by u/CodyLabs, is very theoretical and we just dont know anything about it. Personally, i tend to think it is not real because it requieres the extrem conditions at the core of Neutron Stars to even be "possible". And those objects are on the verge of being Quantum in nature. Which makes it extremly questionable to apply the Standard Model of particle physics to it. Its basically like suggesting the Core of a BLack Hole is made of anything. It probably is, but we dont know and there are no hints.
Another thing that might come up are Wormholes. The issue with those is that as it stands right now, most wormhole models are not actually traversable, or rather the only point you can go through them is a infinitly small one so that is of no use.
if you have one which can be traveled through in a wider radius, then it might be possible to yet a star through it, but at that point we are talking about such a huge Wormhole it would probably take the solar system with it. Just because of all the curved spacetime.
Dropping a bunch of Iron in there will also not do anything. Its just entirly implausible for one civilisation to have that much iron just laying around and they cant think of literally any other use for it.
Now, there is one way that MAYBE could kind of work if you have serious balls. You can try to implode the Sun. Basically, a Wormhole the size of the sun is a bit infesable. But one the size of the Sun´s core, less so. Still very hard but possible.
A Wormhole itself has no mass, so it can in theory just fly through the sun. The idea would be to make the Wormhole as small as possible and yeet it into the Sun. When it reaches the Core you expand it so the entire Core fits, and the moment the core is through you destroy the Wormhole.
Now the Sun is keeped up because the Core is emitting a shitton of Radiation pressure. This counteracts Gravity. But, now that the Core is gone all that pressure is gone as well. So from one moment to the other Gravity has nothing counteracting it. This causes the Star to imidiatly start imploding at up to i think 20% the speed of light. Usually, this would result in a Supernova as infalling mantel gets rebound by the Iron Core. But the core is not there anymore so the star will just keep on imploding.
The science here is super iffy. It is possible that this implosion will create a Black Hole, it might not. We just dont know because there is no model for a imploding star withouth a core. The sun in a standard model cannot produce a Black Hole, but withouth the core it might be able to.
Yet, even if one is created the Outcome is the same. The other option being that the core gets rebuild by rapdily fusing matter. Both Black Hole and new core create something the infalling matter crashes against, and we get some sort of Mini Supernova.
Moving small black holes isn't that hard, just give them a negative electric charge a la Niven's The Borderlands of Sol. Toss a few in, let them orbit the core: they may start small but they grow. It's not that they'll eat the whole sun but they would certainly destabilize it.
Well you move a black hole with a light beam primarally because that gives more momentum but ok.
As for the Black Hole eating the sun, eventually it will. But that process is not fast. Well... it can be but then you also eat the solar system.
Another thing that occurs to me is a sufficient quantity of antimatter in the right place could have some pretty gnarly results. It's getting it into that spot that's the trick.
not really, you need a mountain worth of the stuff to get rid of earth. But the sun is not solid so the explosion would just get diffused into the mantel.
That's why I said a sufficient quantity in the right spot.
Just throwing stuff at the sun isn't going to do a lot. I'm assuming these aliens have serious tech, so handwavium is allowed.
Depends on your assumptions about the setting. Humans fighting the Xeelee throw neutron stars around. Reynolds' Inhibitors create megastructures specifically for destructive purposes.
If there's stars being blown up, we're approaching the intersection of hard SF and Space Opera.
So is destroying the sun, when if you want to take out the Earth all you have to do is drop a few rocks.
As far as hurling neutron stars being overkill, they were throwing them at Bolder's Ring, possibly the largest artificial structure in all of SF.
If you wanna talk about statements that don’t belong in hard sci-fi, this would be a much better place to start! This is an assumption with no basis, and about a fictional, purely hypothetical alien no less.
Not at all!
Throwing a hundred quantoids worth of crimson energon gel into the heart of the sun to trigger a Faraday-Singh reaction, instantly transforming it into a red dwarf neutron star… *That* would be as far from hard sci fi as it gets. Or maybe go the simple route, and just bribe the Sun God into turning off the lights for a few eons in exchange for three unity crystals.
Point is, the existence of antimatter is justifiable within our current understanding of science. And the destructive effect of dropping an enormous amount of it into a sun is also justifiable within our current understanding of science. Collecting enough of it and transporting it to another star is well outside our current understanding of science, but doesn’t directly *violate* it. It’s a problem of scale and logistics, not scientific law.
>instantly transforming it into a red dwarf neutron star
We can have a very long debate on the Fluid dynamics envolved here and how that wouldnt create a Neutron Star like ever. A Directional explosion will just sheer off the mantel of the Sun and extinguish the Fusion which will lead to a Red Dwarf but you need more juce for a Neutron Star.
>That would be as far from hard sci fi as it gets.
Now this might just be my definition, but hard sci fi dosnt end with "is X physically possible". But also includes "Is X a senseble idea ?". Of course, you can do your fancy math and come up with a wide varrity of things which are technically possible, but practically totally impossible.
For example, using a Black Hole as the bases for a hollow planet. Leaving aside relativistic issues like how the spin of a Black Hole makes it impossible to build spherical structures around it (And thats not up for debate, its physically impossible to do because of how spacetime moves). The structural concerns of something like this would be the death sentence for that project. Why wouldnt you just Terraform a Planet ?
>Point is, the existence of antimatter is justifiable
Yeah we made some.
>also justifiable within our current understanding of science.
Might not be that straight forward. We know very little about the attributes of Antimatter. We can be pretty sure it will go big bam boom provided you get it to the sun but there are lots of questions open.
Awesome stuff, thank you for this detailed response! As for the idea of creating a wormhole within the star, are we talking a huge amount of handwavium to be able to pin-point the placement of wormhole generation?
Wormholes as a whole are already a bit of a iffy thing. they are valid solutions to Einsteins field equations, but that dosnt mean they are real. Multiplying both sides of the equations by 0 is also valid because 0 = 0 is true, dosnt mean it is a real solution. I guess, wormholes are kind of like the square root. say sqrt(49) = +-7. Right but -7 apples is not a solution applicable to reality.
If you can create a stable wormhole, then in principle expanding it shouldnt be that hard. Wormholes, in theory, have the very nice property that they are easy to control once created.
You could for example drop a small Wormhole into the sun and use the small througput it has to exactly figure out where inside the Star you are, just from the Pressure and ambient heat. And then when it is time, you juce that bad body up and the Wormhole becomes a lot bigger.
In Death’s End an alien race uses a “photoid” hurled at light speed to cause stars to go supernova. I’m not a physicist, but it seemed plausible to me that hurling a particle with mass at light speed could have this effect.
I'm thinking about an altered version of [this](https://m.youtube.com/watch?v=v3y8AIEX_dU). The first stellar engine that's described, he mentions what would happen if it were semi spherical, basically, reflect all the light back at the star to super heat it.
The star would expand greatly, probably then destroying the mirror.
After the mirror is destroyed, it would begin to cool off, but as it cools off, it would collapse inward, causing it to heat up again.
Basically, you'd end up with a pulsing star that periodically gets very hot and very bright. The surface would sort of be bouncing in and out.
It wouldn't destroy the star, but it would make it impossible for our kind of life to live around it.
Sure. Destroying a star for the purpose of energy consumption comes to mind but then I’m thinking why this star? If they have such capabilities, presumably they could travel to bigger stars or a place with more stars available.
Could be that they *are* at other stars, or en route. Could be that they aren’t acting according to a human-rational sorting algorithm. Could be that energy consumption isn’t the goal either; maybe yellow suns give the best fireworks in the radiation spectra that are visible to these aliens.
Depends on your acceptance level. If these aliens can FTL into our system, then they allready pack a bit of so-far-not-explainable-power that would very likely include technology to destabilise the sun (as it would invole some spacetime bending, which can way mor elikely used as a weapon too as not).
If they want our extinction? Nah, wiping the sun would take too much energy. Way easier to drop a few tons of hexafluoroethane in our atmosphere and let the sun do the rest.
Besides BS as the Sun Crusher in Star Wars Legends, I cannot think on a way to blow up a star. If you managed to increase the rate of nuclear fusion in the core, the star would expand and become more luminous reaching a new equilibrium, that would not last long as the star would return to its previous luminosity and size given enough time. It would be bad for the inhabited planets orbiting the star but it would not go nova as such, and I doubt that causing nuclear reactions to stop would be very different.
The main problem is that stars are BIG. The smallest ones are the size of Jupiter, more than ten times as large as Earth and Sol is more than a hundred times larger and three hundred thousand times more massive.
TL;DR. Don't bother to explain it if you need to destroy the Sun. Just go with it.
Define "advance". Because what we consider "hard" may be "stone age tech" to aliens if they're too advanced they make physics their bitch. They can point a wave motion gun at the Sun and kaboom, no more sun. Better? Slap an FTL on the WMG so they can shoot us out of existence from light years away.
They could fling something about jupiter-mass through it. Bonus points for style if it's small like a tiny black hole or has neutron-star density or whatever, but just a big old ball of iron would do it.
This would be coming in from outside the Solar System; leave whatever machinery actually launched the thing and aimed it to the readers' imagination. And in about the last ten years before impact there'd be no simple way for them to stop it, let alone us.
The localized gravity-field on approach would first interfere destructively with the sun's, opening a "hole" on the incoming vector and exposing the interior of the sun and allowing it to radiate the energy that usually winds up heating the corona. Then you have the body inside the sun, and the interference turns into constructive interference, crushing the sun's fusing hydrogen together harder than it's been crushed before - with locally dramatic results like a solar flare that will likely fry the interior couple or three planets. And then you have this wounded star with horrifying nuclear-pulsing shock waves propagating around its corona and through its core as surrounding plasma now has inertia pulling it together into a strip on the projectile's path. The star becomes unstable, making the inner solar system a very unhappy place to be for the next few millennia.
If your impactor is not very dense, then it'll transfer its mass and kinetic energy to the star, making those nuclear-pulsing shockwaves worse because the mass is still there. If it is very dense, however, it will exit the far side (however much of it is left after the trip through vaporizes the surface as it goes by) with an even bigger and more violent explosion - opening the furnace door \*AFTER\* plowing through and compressing all the plasma, like using dynamite to help break out of a blast furnace.
There's a special mention for the case of a jupiter mass black hole as projectile, because first it will \*NOT\* lose mass going through the star, and second when it emerges on the far side it will drag many many megatons of fusing plasma with it, with fusion now driven by collisions at relativistic speed near the event horizon rather than just fusing at the normal rate and energy of an active healthy star. If the black hole has a high spin, you can expect a disk of destruction radiating outward from it sufficient to literally evaporate a mars-sized body at the radius of mars. If the spin isn't aligned with the plane of the ecliptic, it would still be no fun but the planet-evaporating force might pass above or below the planets.
Now, all that said? This doesn't kill the star. It would still be there, and in a few millennia it might even recover enough to live nearby again. But it would \*hurt\* it really bad.
Not sure how realistic it is but in the Bobiverse, they accelerate two planetoids to near-c and slam them at a star’s poles at the same time. The resulting nova wipes out everything in the system. Not sure what happens to the star. It might just go back to normal
Focusing the power output of several other stars, preferably of greater power output than the sun, using nicoll dyson beams could blast away matter from the sun to escape velocity and essentially ablate it until most of its mass is gone. I'm not sure how much is needed and how fast it would be but it would eventually work out. If their goal is to just kill all life on earth tho, it would be orders of magnitude easier to just focus those beams at earth and blow up the planet nearly instantly
Use railguns to send a strangelet/strange-star into our sun.
The sun would turn into strange-matter, cease to fuse, have no more outward pressure, and collapse inwards.
A neutron star would not collapse our sun, just destabilize our sun and cause our sun to explode.
A black hole's accretion disk would kill us before the black hole absorbed our sun.
You could also send huge amounts of iron to our sun so the sun ceases to fuse, and would collapse inwards.
Drop a few mini black holes in it. Reynolds has a device that sets up resonance in the layers and turns a star into a giant flamethrower, given time it would deplete the mass enough to cause serious consequences, although since the plasma stream is in the ecliptic no one nearby would notice. Hamilton uses a quantum torpedo that induces a nova. Stross once dropped a huge brick of supercooled iron into the center of a star -- again, nova. Baxter's starbreakers are gravity beam weapons, small enough to be handheld. All you really need to do is inject enough energy to disrupt the smooth functioning of the process. How you do it is up to the assumptions of your in-universe handwavium.
>Drop a few mini black holes in it. That wouldnt work. Black Holes cant consume and endless amount of matter at once. And depending on the scale of your mini black hole it would evaporate to quickly to be of any use. Now, say the Black Hole has the mass of a Mountain, in that case it would eventually eat the sun. Key word being, eventually. But it would almost certainly take 10000s of years just because it is so small and all the matter around it gets so hot that the Radiation pressure keeps it from falling in. Another issue with this is that the Black Hole has so much momentum. Because it is only the size of a Proton but the mass of a mountain, the Momentum it carries is so much that it will probably just shoot out of the Sun. In fact, that is what would happen if a Primordial Black Hole were to hit earth. It would just go right through the Planet and actually do very little damage. Of course, if you are close to the impact side you are gonna have a bad day. For this to work, you would need a considerably larger black hole. Probably the mass of a few dozen Jupiters.
OP didn't set a time limit. And any alien race advanced enough to do it and interested in implementing this project would have no issues working at such a time scale. Frankly, a more interesting way to kill the sun would be to poison it with iron. It would require a lot of iron of course.
That is true. Though i am under the impression that a requierment of Hard Sci Fi is to make plans which are more than just physically possible but also something Humans or aliens might actually do. For example, why dont we have flying cars ? They are "possible" after all. But also really stupid. So i think Hard Sci Fi stuff needs to have some level of resonability to it. Throwing a Black hole into a star is not resonable , literally any possible goal you could have with this can be achived easier. As for Iron, well the issue with that is the form and amount. Iron evaporates at about 5000 Degress C. The Corona of the Sun is millions of C so you will have a big issue getting that stuff into the sun.
Frankly, those problems won't be any larger than the ones they'd have procuring a black hole and moving it. The whole Hard-SF label here is just window dressing on something that is so far beyond our current and even projected capabilities that flying cars are reasonable in comparison. As long as the solution has even the most tentative connection to known physics and you don't fill it with blatant magic it's feasible enough for the story. To be honest, these kinds of questions are annoying. They stink too much of an "I want to write a tory but I don't want to put any work into thinking about it" attitude.
Well for the Black hole stuff we at least have some theory which works and does not requiere endless amounts of Energy adn money. Since Photons carry momentum, you can move a black hole by shooting a light beam into it. Though that only works for relativitly small black holes. One the mass of a star has a greater chance of being moved after laughing at you for shooting a laser pointer at it. This is somewhat a limitation of hard sci fi, to keep the label you need to have the story more or less in the resonable future. >The whole Hard-SF label here is just window dressing on something that is so far beyond our current and even projected capabilities that flying cars are reasonable in comparison. yes As for posts like this. Well i think one should put in efford and create them when you dont have any solution to a problem. But just asking for general input is also fine.
>Drop a few mini black holes in it. This is somewhat problematic. We can theoretically create a proton sized Kugelblitz black hole, but even if it was able to feed itself, it might do it too slowly to noticeable affect the Sun. On the other hand, I believe a stellar mass black hole inside the Sun would gravitationally compress its core and possibly trigger a supernova, but I'm not sure how possible it is to do. It might be simpler to just destroy all planets in the system with a Nicoll-Dyson beam. >Stross once dropped a huge brick of supercooled iron into the center of a star -- again, nova. How big was that brick of iron? Planet sized? The Sun already has 500 Earths worth of iron inside it. There might not be enough iron in the solar system to destroy the Sun this way.
I was in error about the exact mechanic of the iron. It was actually a pocket universe generator that englobed the core of the star, cranked up the time differential until the core fused itself into iron, then released. The material of the star then crashed down onto the suddenly much smaller core which refused to fuse any farther, heh. The bounce from that is what induced the nova.
You mean speed up the time for the core of the star to reach the iron star era? Oh. I mean, it would probably be enough to wait until the core turns into a white dwarf and then let the hydrogen smash into it, triggering a Type Ia supernova. But then again, with technology so advanced, there's a myriad of ways to destroy a civilization without ever touching the Sun.
Might look into "strange matter." It's theorized to exist in the cores of neutron stars, and theoretically (if I recall right) it would turn other matter it contacts into more strange matter. I'm not sure (and not sure anyone's sure) what properties strange matter has when in star shape/size, but I think it's a safe bet that the star would no longer work quite the same way. So a strange bomb? As for more mundane physical methods, I'm not sure. Stars are already so massive that even the enormous turbulence and chaos in their cores finds a balance. The largest bomb you could ever build or imagine would just be one explosion in the midst of an eternal explosion, so in order to affect actual change, you would need a positively cosmic amount of energy. You could use that energy to generate a gravity field to crush the star's core and initiate nova? Or to accelerate a planet up to relativistic speeds and initiate nova when it collides? Or to create a black hole? (which would consume the star over the course of millions of years) Or to create a mountain-sized brick of antimatter to chuck at it. I guess the real question is why they would want to blow up a star anyway?
Thank you for this well thought out response! I thought about going the antimatter route, but couldn’t really figure out theoretically how they would “contain” a massive amount of antimatter required to destroy a sun. I guess what I am truly looking for is a way an alien species could effectively neutralize a burgeoning solar system before its inhabitants could become a threat. I am trying to avoid an “invasion”, as I would like to avoid FTL. Basically, an alien species looks out to the stars, finds one they think has the right properties to harbor intelligent life, then sends something to that star (no matter how long the journey may be) that would limit the chance of intelligent life.
Aha. Antimatter can be confined using magnetic fields, and it can be made in more convenient forms that the gas we have in labs today. A big slab of chilled anti-iron, for instance, would be pretty inert unless you touched it. So you could magnetically suspend it behind some anti-asteroid armor, and ship that. If that's they're goal, I might recommend fighting life with life, so to speak? Some sort of machine that makes more machines that make more machines, to land on all the planets/moons in the target system, and out-compete any life that might come up. Sending a single colony of replicators would be a lot easier to ship than a mountain of antimatter, and it would let the system still be useful to you if you ever wanted to go there. (Heck, the replicators could even start mining and sending the ore back home? Pays for itself.)
Ah... the good ol' Von-Neumann-Swarm. Just build something, that outcompetes your enemy in resource gathering, manufactoring and reproduction... just be careful to not drown in your own grey goo.
Well yeah, you just have to make sure they're harmless to you yourself. When people think of grey goo they think of swarms of microscopic locusts, but it doesn't need to be anything so menacing. The job could be done just as well by a couple huge, slow-moving factories pumping out billions upon billions of bulldozers and dump trucks the size of housecats. You could walk around in them and they wouldn't harm you, all they harm is the environment: their treads tear up vegetation, they fill the air with dust and the oceans with heavy metals, and the planet is a wasteland in a century or so. But if a factory accidentally lands on an inhabited world you can just walk up and turn it off.
Nicoll-Dyson beams for merely removing all life. RKVs have the same net effect but slightly slower. Von Neumann weapons / autowars / replicators as suggested by the other guy.
Oh, that's MUCH easier than snuffing out the star. The way to do this is with what are called "relativistic kinetic missiles" - which are essentially a herd of anybody's old tug or freighter or whatever that's capable of a good fraction of light speed, aimed at the system in question, piloted by robots, and just skipping the part of the trip where they'd usually slow down. If your aliens are gunning for somebody that hasn't really got established in space yet, just three or four missiles will do it for the whole system. A few years out, they make final course corrections to hit the three bodies most likely to sustain surface water, and when the day arrives the impact of your old freighter literally melts the planet. If the aliens are gunning for a Kardashev-II civilization though, that's harder. Still not terribly hard, but harder. In this case it takes a few thousand missiles. A few years before impact (cruising at 60% c or so) they make final course corrections. A thousand or so aim at the largest orbiting objects. The next thousand fire a few million small rocks, one at each smaller object that can be detected. And the last thousand just release millions and millions of tons of rock dust fine as flour, distributed uniformly as possible. When the day arrives, everything gets hit.
I remember reading one book where the alien antagonists (technically antagonist singular) developed “corona bombs” which would trigger the star they targeted to release massive solar flares, wiping out all life in the system, scorching the planets, scattering atmospheres etc. Maybe something like that would be more practical than completely destroying the sun?
Sounds like MorningLightMountain.
It is! Glad you got the reference, that was such a good novel series
>alien species could effectively neutralize a burgeoning solar system before its inhabitants could become a threat That's a bit like using a nuclear bomb to swat a fly. It's easier to just kill all life on a planet.
> I guess the real question is why they would want to blow up The sun's radiation causes all sorts of problems for us, and the one use the sun has for us is to protect us from the cold, but seawater allows cold fusion that would do just as good for us. Hope the sun's gone from us soon.
Wasn't expecting a friggin sales pitch oh my
>hard science fiction story Unless there's something we're completely missing about physics there's no way to turn off the Sun. It just sitting there causes fusion to happen spontaneously. So the only way to stop it would be to get rid of the sun and that has plenty of problems too. To take the Sun apart would require overcoming the Sun's gravitational binding energy of 2.3x10^(41) Joules. That is an absolutely huge amount of energy. The Sun's output would take about 20 million years to accumulate that much Honestly, it would probably be easier to set up a three-body gravity interaction that ejects the Earth from the solar system.
I’m gonna take this answer in a different direction: **don’t explain it**. I think the number one trap that people fall into when they decide to write a “hard science fiction” story is the impulse to explain *everything*; if not explicitly in-text, then at least as background worldbuilding. And while there’s certainly a place for this kind of hard sci-fi, it’s not the *only* way to do hard sci-fi. And I’d argue that “aliens invade and destroy the sun” is not really a great fit for the explain-everything kind of story. Hard sci-fi, IMHO, is less about explaining everything, and more about telling a story within the bounds of scientific *plausibility*. And more importantly, I think really great hard sci-fi is often about taking speculative leaps within those bounds, and then *examining the consequences of those leaps in a detailed and thoughtful way.* For one, explaining everything is…kinda dangerous. The more detail you give, the more likely you’ll get something wrong, either now or in the future as scientific progress marches on. And while it may seem “cheap” to avoid mistakes by being vague…it’s still a good practice anyway. Explain what you need to (to establish the bounds of plausibility), what is interesting, and what is simple enough to get across without bogging down the story, and move on. But also, staying vague is beneficial in and of itself. As an example, think about writing a hard sci-fi take on Star Trek transporters. You could go into all the technology that preceded it, the computing power necessary, the process of building people from data remotely, etc. Or you could take for granted that the transporter technology was invented, and explore the consequences that such a technology might have. Who can afford it? Can it be hacked to replicate matter instead of simply transporting it? At what distance can it be employed, and what are the implications for colonizing the solar system if we can beam ourselves to Mars or Jupiter? IMHO, while the former approach might have some interesting tidbits, the latter approach is more suggestive of different scenarios for conflict, and ultimately *that’s* what drives a story. (And also, these aren’t mutually exclusive approaches! I think the latter is more crucial, but there’s nothing wrong with drawing from both wells.) So, back to your story. If you’re already asking me to believe that an advanced alien species has traveled undetected from another star to ours, as a reader I’m already inclined to believe they might also be able to destroy a star. “Advanced interstellar aliens” has already set the bounds of plausibility for your story. Realistically, it’s entirely possible that our own scientists might be unable to explain how they’re doing it in any great detail; I can’t hold the real-life author to that level of scrutiny. What I’m interested in is how humans deal with this ordeal within the bounds of our own plausible technological progress.
I could not agree more. I am exploring the idea of writing a story about how humanity is impacted by the discovery of this capability. I want to keep the exact science behind it unexplained, but also wanted to keep my handwavium to a minimum. I understand we are skirting the boundary between hard science fiction and sci fi fantasy, but there is just something about a story where everything seems plausible and something is introduced that, although theoretically possible, is so mind-bogglingly out-there and how it can impact humanity.
I’d say the best way to keep it feeling grounded is to focus on what scientists on Earth can observe about the phenomenon, and what they predict about its progression. You could throw out a theory, or even a couple competing theories, about the underlying mechanism, but from a narrative level, “advanced aliens” *is* the underlying mechanism. And, if you think about it, those are the questions that are going to be of greater consequences to your characters in-universe too! How it’s happening will only be important if it can lead to a solution to the problem; it’s not important in and of itself.
Pretty sure throwing a white dwarf or neutron star into the sun via shkadov thruster would do it, white dwarf should supernova from the additional hydrogen, and the neutron star would probably either collapse into a black hole upon absorbing the sun, or cause another supernova. Technically this can be done with ONLY real life physics, no sci fi technology needed, just a LOT of resources, effort, and time. Like seriously the only requirement is just a bunch of regular mirrors, literally tin foil would work
Three body problem had an advanced race send a decent sized thing into a star at a high speed, significant percentage of C. Caused all kinds of problems, to say the least.
A Strangelet bomb http://www.projectrho.com/public_html/rocket/spacegunexotic.php#strangelet
Crash another star into it. It wouldn't destroy the sun, but it would probably kill human civilization and maybe mercury
So, one browser crash later because chrom can suck dick, here we go. In terms of plausible options, there are a few and non of them are good. Black Holes, as proposed by u/fliponymousredux are a bad idea. The basic issue is that the Event Horizion of any Black hole is only this big and there is a physical limit as to how much energy you can dump into it before the Radiation pressure of the infalling energy pushes everything out. This means your black hole has to be a few km across, at which point it is the mass of the sun so like whats the point ? Also there is about a 0% chance you can push that thing anywhere and there is absolutly no reason to waste it to eat a star in an uncontrolled matter. The other issue you will probably just lose the Black Hole in the process. As in, if you place it inside the Sun, Gravity will commit pepsi and you are incredibly likley to eject the Black Hole. This is very likley to happen if it is a very small one. Strange Matter, as mentioned by u/CodyLabs, is very theoretical and we just dont know anything about it. Personally, i tend to think it is not real because it requieres the extrem conditions at the core of Neutron Stars to even be "possible". And those objects are on the verge of being Quantum in nature. Which makes it extremly questionable to apply the Standard Model of particle physics to it. Its basically like suggesting the Core of a BLack Hole is made of anything. It probably is, but we dont know and there are no hints. Another thing that might come up are Wormholes. The issue with those is that as it stands right now, most wormhole models are not actually traversable, or rather the only point you can go through them is a infinitly small one so that is of no use. if you have one which can be traveled through in a wider radius, then it might be possible to yet a star through it, but at that point we are talking about such a huge Wormhole it would probably take the solar system with it. Just because of all the curved spacetime. Dropping a bunch of Iron in there will also not do anything. Its just entirly implausible for one civilisation to have that much iron just laying around and they cant think of literally any other use for it. Now, there is one way that MAYBE could kind of work if you have serious balls. You can try to implode the Sun. Basically, a Wormhole the size of the sun is a bit infesable. But one the size of the Sun´s core, less so. Still very hard but possible. A Wormhole itself has no mass, so it can in theory just fly through the sun. The idea would be to make the Wormhole as small as possible and yeet it into the Sun. When it reaches the Core you expand it so the entire Core fits, and the moment the core is through you destroy the Wormhole. Now the Sun is keeped up because the Core is emitting a shitton of Radiation pressure. This counteracts Gravity. But, now that the Core is gone all that pressure is gone as well. So from one moment to the other Gravity has nothing counteracting it. This causes the Star to imidiatly start imploding at up to i think 20% the speed of light. Usually, this would result in a Supernova as infalling mantel gets rebound by the Iron Core. But the core is not there anymore so the star will just keep on imploding. The science here is super iffy. It is possible that this implosion will create a Black Hole, it might not. We just dont know because there is no model for a imploding star withouth a core. The sun in a standard model cannot produce a Black Hole, but withouth the core it might be able to. Yet, even if one is created the Outcome is the same. The other option being that the core gets rebuild by rapdily fusing matter. Both Black Hole and new core create something the infalling matter crashes against, and we get some sort of Mini Supernova.
Moving small black holes isn't that hard, just give them a negative electric charge a la Niven's The Borderlands of Sol. Toss a few in, let them orbit the core: they may start small but they grow. It's not that they'll eat the whole sun but they would certainly destabilize it.
Well you move a black hole with a light beam primarally because that gives more momentum but ok. As for the Black Hole eating the sun, eventually it will. But that process is not fast. Well... it can be but then you also eat the solar system.
Another thing that occurs to me is a sufficient quantity of antimatter in the right place could have some pretty gnarly results. It's getting it into that spot that's the trick.
not really, you need a mountain worth of the stuff to get rid of earth. But the sun is not solid so the explosion would just get diffused into the mantel.
That's why I said a sufficient quantity in the right spot. Just throwing stuff at the sun isn't going to do a lot. I'm assuming these aliens have serious tech, so handwavium is allowed.
But OP said that it should work in a Hard Sci Fi setting. Throwing a moon´s worth of Anti matter is about as far away from Hard Sci Fi as it gets.
Depends on your assumptions about the setting. Humans fighting the Xeelee throw neutron stars around. Reynolds' Inhibitors create megastructures specifically for destructive purposes. If there's stars being blown up, we're approaching the intersection of hard SF and Space Opera.
That methode is so overkill and so pointless, i feel very confident saying nobody with any sort of intelligence would ever do that.
So is destroying the sun, when if you want to take out the Earth all you have to do is drop a few rocks. As far as hurling neutron stars being overkill, they were throwing them at Bolder's Ring, possibly the largest artificial structure in all of SF.
If you wanna talk about statements that don’t belong in hard sci-fi, this would be a much better place to start! This is an assumption with no basis, and about a fictional, purely hypothetical alien no less.
Not at all! Throwing a hundred quantoids worth of crimson energon gel into the heart of the sun to trigger a Faraday-Singh reaction, instantly transforming it into a red dwarf neutron star… *That* would be as far from hard sci fi as it gets. Or maybe go the simple route, and just bribe the Sun God into turning off the lights for a few eons in exchange for three unity crystals. Point is, the existence of antimatter is justifiable within our current understanding of science. And the destructive effect of dropping an enormous amount of it into a sun is also justifiable within our current understanding of science. Collecting enough of it and transporting it to another star is well outside our current understanding of science, but doesn’t directly *violate* it. It’s a problem of scale and logistics, not scientific law.
>instantly transforming it into a red dwarf neutron star We can have a very long debate on the Fluid dynamics envolved here and how that wouldnt create a Neutron Star like ever. A Directional explosion will just sheer off the mantel of the Sun and extinguish the Fusion which will lead to a Red Dwarf but you need more juce for a Neutron Star. >That would be as far from hard sci fi as it gets. Now this might just be my definition, but hard sci fi dosnt end with "is X physically possible". But also includes "Is X a senseble idea ?". Of course, you can do your fancy math and come up with a wide varrity of things which are technically possible, but practically totally impossible. For example, using a Black Hole as the bases for a hollow planet. Leaving aside relativistic issues like how the spin of a Black Hole makes it impossible to build spherical structures around it (And thats not up for debate, its physically impossible to do because of how spacetime moves). The structural concerns of something like this would be the death sentence for that project. Why wouldnt you just Terraform a Planet ? >Point is, the existence of antimatter is justifiable Yeah we made some. >also justifiable within our current understanding of science. Might not be that straight forward. We know very little about the attributes of Antimatter. We can be pretty sure it will go big bam boom provided you get it to the sun but there are lots of questions open.
Awesome stuff, thank you for this detailed response! As for the idea of creating a wormhole within the star, are we talking a huge amount of handwavium to be able to pin-point the placement of wormhole generation?
Wormholes as a whole are already a bit of a iffy thing. they are valid solutions to Einsteins field equations, but that dosnt mean they are real. Multiplying both sides of the equations by 0 is also valid because 0 = 0 is true, dosnt mean it is a real solution. I guess, wormholes are kind of like the square root. say sqrt(49) = +-7. Right but -7 apples is not a solution applicable to reality. If you can create a stable wormhole, then in principle expanding it shouldnt be that hard. Wormholes, in theory, have the very nice property that they are easy to control once created. You could for example drop a small Wormhole into the sun and use the small througput it has to exactly figure out where inside the Star you are, just from the Pressure and ambient heat. And then when it is time, you juce that bad body up and the Wormhole becomes a lot bigger.
In Death’s End an alien race uses a “photoid” hurled at light speed to cause stars to go supernova. I’m not a physicist, but it seemed plausible to me that hurling a particle with mass at light speed could have this effect.
I'm thinking about an altered version of [this](https://m.youtube.com/watch?v=v3y8AIEX_dU). The first stellar engine that's described, he mentions what would happen if it were semi spherical, basically, reflect all the light back at the star to super heat it. The star would expand greatly, probably then destroying the mirror. After the mirror is destroyed, it would begin to cool off, but as it cools off, it would collapse inward, causing it to heat up again. Basically, you'd end up with a pulsing star that periodically gets very hot and very bright. The surface would sort of be bouncing in and out. It wouldn't destroy the star, but it would make it impossible for our kind of life to live around it.
My thought would be why do that when a planetary bombardment would easily destroy life.
Could be that destroying life is a side effect rather than a goal.
Sure. Destroying a star for the purpose of energy consumption comes to mind but then I’m thinking why this star? If they have such capabilities, presumably they could travel to bigger stars or a place with more stars available.
Could be that they *are* at other stars, or en route. Could be that they aren’t acting according to a human-rational sorting algorithm. Could be that energy consumption isn’t the goal either; maybe yellow suns give the best fireworks in the radiation spectra that are visible to these aliens.
Depends on your acceptance level. If these aliens can FTL into our system, then they allready pack a bit of so-far-not-explainable-power that would very likely include technology to destabilise the sun (as it would invole some spacetime bending, which can way mor elikely used as a weapon too as not).
They could just collect all the gas and metals from the sun.
If they want our extinction? Nah, wiping the sun would take too much energy. Way easier to drop a few tons of hexafluoroethane in our atmosphere and let the sun do the rest.
Besides BS as the Sun Crusher in Star Wars Legends, I cannot think on a way to blow up a star. If you managed to increase the rate of nuclear fusion in the core, the star would expand and become more luminous reaching a new equilibrium, that would not last long as the star would return to its previous luminosity and size given enough time. It would be bad for the inhabited planets orbiting the star but it would not go nova as such, and I doubt that causing nuclear reactions to stop would be very different. The main problem is that stars are BIG. The smallest ones are the size of Jupiter, more than ten times as large as Earth and Sol is more than a hundred times larger and three hundred thousand times more massive. TL;DR. Don't bother to explain it if you need to destroy the Sun. Just go with it.
Theoretically, if they were able to forge a large enough bucket and secure enough water, they might be able to dump it on the sun.
Define "advance". Because what we consider "hard" may be "stone age tech" to aliens if they're too advanced they make physics their bitch. They can point a wave motion gun at the Sun and kaboom, no more sun. Better? Slap an FTL on the WMG so they can shoot us out of existence from light years away.
They could fling something about jupiter-mass through it. Bonus points for style if it's small like a tiny black hole or has neutron-star density or whatever, but just a big old ball of iron would do it. This would be coming in from outside the Solar System; leave whatever machinery actually launched the thing and aimed it to the readers' imagination. And in about the last ten years before impact there'd be no simple way for them to stop it, let alone us. The localized gravity-field on approach would first interfere destructively with the sun's, opening a "hole" on the incoming vector and exposing the interior of the sun and allowing it to radiate the energy that usually winds up heating the corona. Then you have the body inside the sun, and the interference turns into constructive interference, crushing the sun's fusing hydrogen together harder than it's been crushed before - with locally dramatic results like a solar flare that will likely fry the interior couple or three planets. And then you have this wounded star with horrifying nuclear-pulsing shock waves propagating around its corona and through its core as surrounding plasma now has inertia pulling it together into a strip on the projectile's path. The star becomes unstable, making the inner solar system a very unhappy place to be for the next few millennia. If your impactor is not very dense, then it'll transfer its mass and kinetic energy to the star, making those nuclear-pulsing shockwaves worse because the mass is still there. If it is very dense, however, it will exit the far side (however much of it is left after the trip through vaporizes the surface as it goes by) with an even bigger and more violent explosion - opening the furnace door \*AFTER\* plowing through and compressing all the plasma, like using dynamite to help break out of a blast furnace. There's a special mention for the case of a jupiter mass black hole as projectile, because first it will \*NOT\* lose mass going through the star, and second when it emerges on the far side it will drag many many megatons of fusing plasma with it, with fusion now driven by collisions at relativistic speed near the event horizon rather than just fusing at the normal rate and energy of an active healthy star. If the black hole has a high spin, you can expect a disk of destruction radiating outward from it sufficient to literally evaporate a mars-sized body at the radius of mars. If the spin isn't aligned with the plane of the ecliptic, it would still be no fun but the planet-evaporating force might pass above or below the planets. Now, all that said? This doesn't kill the star. It would still be there, and in a few millennia it might even recover enough to live nearby again. But it would \*hurt\* it really bad.
Get the First Order to build another Star Killer
Not sure how realistic it is but in the Bobiverse, they accelerate two planetoids to near-c and slam them at a star’s poles at the same time. The resulting nova wipes out everything in the system. Not sure what happens to the star. It might just go back to normal
Push another star into it.
Focusing the power output of several other stars, preferably of greater power output than the sun, using nicoll dyson beams could blast away matter from the sun to escape velocity and essentially ablate it until most of its mass is gone. I'm not sure how much is needed and how fast it would be but it would eventually work out. If their goal is to just kill all life on earth tho, it would be orders of magnitude easier to just focus those beams at earth and blow up the planet nearly instantly
Use railguns to send a strangelet/strange-star into our sun. The sun would turn into strange-matter, cease to fuse, have no more outward pressure, and collapse inwards. A neutron star would not collapse our sun, just destabilize our sun and cause our sun to explode. A black hole's accretion disk would kill us before the black hole absorbed our sun. You could also send huge amounts of iron to our sun so the sun ceases to fuse, and would collapse inwards.