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Thread: Destroying a star
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2019-12-02, 03:01 PM (ISO 8601)
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Re: Destroying a star
That page you linked to is also using Kepler's Third Law, like I did, but it notes this near the bottom of the first section:
"The time to traverse half the distance R, which is the infall time from R along an eccentric orbit, is the Kepler time for a circular orbit of R/2 (not R), which is (1/32)1/2 times the period P of the circular orbit at R. For example, the time for an object in the orbit of the Earth around the Sun, to fall into the Sun if it were suddenly stopped in orbit, would be P / 32 {\displaystyle P/{\sqrt {32}}} P/{\sqrt {32}}, where P is one year. This is about 64.6 days."
I'm not sure I understand what that means, but it suggests my calculation was essentially correct but I used the wrong multiplication factor--so this is saying that our hypothetical Persephone would take 126.5 years to fall in with its orbital period of 716 years, still *way* longer than the timescale implied in the novel.
@halfeye: Kepler works just as well for circular orbits as for ellipses. The semimajor axis of a perfectly circular orbit is just its radius.Last edited by factotum; 2019-12-02 at 03:04 PM.
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2019-12-02, 03:52 PM (ISO 8601)
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2019-12-02, 03:56 PM (ISO 8601)
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Re: Destroying a star
"Interdum feror cupidine partium magnarum Europae vincendarum"
Translation: "Sometimes I get this urge to conquer large parts of Europe."
"If you don't get those cameras out of my face, I'm gonna go 8.6 on the Richter scale with gastric emissions that'll clear this room."
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2019-12-03, 11:19 PM (ISO 8601)
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Re: Destroying a star
Maybe I'm missing something, but if I can stop a planet, and want to kill everybody on a planet, wouldn't I just stop that planet?
Blood-red were his spurs i' the golden noon; wine-red was his velvet coat,
When they shot him down on the highway,
Down like a dog on the highway,And he lay in his blood on the highway, with the bunch of lace at his throat.
Alfred Noyes, The Highwayman, 1906.
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2019-12-04, 12:17 AM (ISO 8601)
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Re: Destroying a star
Range.
Again, the 'dark forest' hypothesis for alien relationships requires that species be able to destroy each other immediately upon detection. The central idea is that if it becomes known that some sapient species exists around a star they will be destroyed as soon as the speed of light permits said destruction to occur. However, depending upon how far away you are a planet may well be invisible no matter how good your instruments, but the star's position is quite obvious. So you attack the star.
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2019-12-04, 12:20 AM (ISO 8601)
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- May 2016
Re: Destroying a star
I'm not familiar with the story in question, but I'd think that the people who lived on the planet might be able to do something about that - sounds to me like the story essentially has somebody strapping a giant rocket to the planet and then firing the rocket in such a manner as to cancel out the planet's orbital velocity and maybe give it a push towards the sun, which might be the kind of thing that you can't really do in the face of organized opposition.
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2019-12-04, 02:26 AM (ISO 8601)
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Re: Destroying a star
The giant rocket in question was using the atmosphere of the gas giant as fuel. It wouldn't really be possible to do that on a habitable planet. (OK, realistically it wouldn't be possible in a gas giant either because regular hydrogen is actually really, really difficult to fuse into helium, but it's less of a stretch than trying to fuse *oxygen*).
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2019-12-04, 06:36 PM (ISO 8601)
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Re: Destroying a star
It seems to me that if you can launch a projectile at a star from across interstellar space, you can launch something that has an antenna hooked up to a computer that does a little bit of processing and aims at the planet with all the radio signals. Hell, launch a lot of them; rendering a planet utterly uninhabitable requires a lot less oomph than blowing up a star. Add a bit of coordination between your projectiles, and you can probably smash every reasonably large rocky body in the system into a twisted hellscape. Compared to the tech level necessary to fire a weapon between solar systems in the first place, this seems like kindergarten level stuff.
Blood-red were his spurs i' the golden noon; wine-red was his velvet coat,
When they shot him down on the highway,
Down like a dog on the highway,And he lay in his blood on the highway, with the bunch of lace at his throat.
Alfred Noyes, The Highwayman, 1906.
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2019-12-04, 06:57 PM (ISO 8601)
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Re: Destroying a star
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2019-12-04, 07:54 PM (ISO 8601)
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Re: Destroying a star
The ability to make effective course corrections while traveling at relativistic velocities is somewhat tricky. But yes, it is still probably viable to kill the planets with a proper engineering fix and requiring far less overall energy expenditure, but Cixin Liu needed stars to blow up as part of a plot point in The Dark Forest that blowing up planets wouldn't have fulfilled, so he blew up some stars.
Originally Posted by TVTyrant
For example, it is still quite possible that we will go to the stars, but it's becoming fairly clear that if we do so it won't be as flesh and blood entities. Instead it will be as brains in jars or digital people or perhaps it will be our AI creations that inherit the cosmos. This sort of thing appears to be far less appealing than tales of heroic daring by otherwise recognizable humans in the 'final frontier.' The accessibility level of something like Greg Egan's Diaspora is much, much lower than Star Trek, even though both are ultimately about exploring the cosmos and seeking to solve its mysteries.
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2019-12-05, 01:55 AM (ISO 8601)
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Re: Destroying a star
Blowing up a planet does not stop a space-faring civilisation from shooting back. In fact it pretty much guarantees that they will try to. The trick then is changing a single relativistic projectile into something that scorches the whole system. You don't want to miss a few asteroid habitats, or you'll be facing return fire in a few centuries.
The idea, it seems, is to hit the star hard enough, and in the right way, to stop fusion in the core briefly. The outer layers of the star will then start falling inward. By the time fusion restarts the inertia of those layers means it will start big. The resulting nova then cleanses the whole system for you.
On the bright side, if this was happening I suspect we would see it. The explosion would be bright, but noticeably smaller than we could explain with physics.Last edited by Excession; 2019-12-05 at 02:42 AM.
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2019-12-05, 02:52 AM (ISO 8601)
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Re: Destroying a star
That's been fairly clear ever since Einstein formulated his theories of relativity more than a century ago now. Any time an SF writer invoked hyperspace, warp drive, wormholes or whatever they're using something known to be impossible. I think this is why the likes of the Expanse is set entirely within the Solar System, because that's more realistic (even if it requires impossibly efficient fusion drives to make the whole thing work).
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2019-12-05, 05:29 PM (ISO 8601)
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2019-12-05, 05:49 PM (ISO 8601)
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2019-12-06, 02:03 AM (ISO 8601)
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2019-12-06, 02:47 AM (ISO 8601)
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Re: Destroying a star
Not quite: causality will still work just in a way that makes you have a headache. There are even publications explicitly solving simplified versions of grandfather paradox for example (ball is thrown into a wormhole and hits itself off the course so it never enters the portal in the first place). Those situations only show that you cannot find the solution in an iterative manner but they still exist. Worse yet: one of the most elegant interpretations of quantum electrodynamics requires you to consider antimatter as regular matter moving back in time and in this case virtual particles are simply ontological loops (they exist, because they made themselves exist in the past).
In a war it doesn't matter who's right, only who's left.
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2019-12-06, 02:27 PM (ISO 8601)
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Re: Destroying a star
Um, you do know that the Expanse has branched out into other star systems using alien created wormholes, right?
Some of the tests they have been doing with the double slit experiment have really been playing games with quantum physics (even worse than normal). The Delayed Choice Double Slit experiment gave results that the particles acted as if they were being observed before they actually were observed. (Result of an action being taken before action the action took place.) The Delayed Choice Quantum Eraser Double Slit gave results that indicate the particles "chose" the path they took after they ended the journey. No such thing as time?Last edited by HandofShadows; 2019-12-06 at 02:46 PM.
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2019-12-06, 02:55 PM (ISO 8601)
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Re: Destroying a star
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2019-12-09, 02:59 AM (ISO 8601)
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2019-12-09, 04:01 PM (ISO 8601)
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Re: Destroying a star
Step two technology technology test for the infinite probability drive IMO.
Step one being hot tea.
As for destroying a star. Compressed star plasma is phenomenally dense....like slows light down to the point of taking 10K years to make it the radius of our sun distance (very very not a straight line).
Hiting it with a relativistic object could make a powerful energy event at the surface of the star which could well mess up civilizations, but unless your object is, say a black or brown dwarf I'm not seeing how that would work.
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2019-12-09, 05:49 PM (ISO 8601)
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Re: Destroying a star
Spoiler: I'm a writer!Spoiler: Check out my fanfiction[URL="https://www.fanfiction.net/u/7493788/Forum-Explorer"here[/URL]
]Fate Stay Nano: Fate Stay Night x Magical Girl Lyrical Nanoha
I Fell in Love with a Storm: MLP
Procrastination: MLP
Spoiler: Original FictionThe Lost Dragon: A story about a priest who finds a baby dragon in his church and decides to protect them.
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2019-12-09, 07:07 PM (ISO 8601)
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Re: Destroying a star
I mean you're not actually wrong.
If you could introduce a sufficient mass of iron into a star you'd interrupt the fusion process and it would go out (quite violently).
Of course "a sufficient mass" would be ~8 times the mass of the star (for a main sequence G class like our sun).
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2019-12-10, 09:08 AM (ISO 8601)
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2019-12-10, 11:10 AM (ISO 8601)
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Re: Destroying a star
A you sure about that being 8 solar masses of iron required to shut down fusion? I'm pretty sure if you gathered only 3 solar masses of iron into a sphere you'd have a black hole in short order, without the need to introduce it to a star.
Edit: Wikipedia tells me the maximum mass for a neutron star is only 2.16 solar masses. Anything more than that will collapse into a black hole unless it's got fusion (or something else) going on in its core to provide enough energy to prevent it.Last edited by Lord Torath; 2019-12-10 at 11:15 AM.
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2019-12-11, 12:53 AM (ISO 8601)
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Re: Destroying a star
At a basic level, all stars are trying to destroy themselves constantly. They're not finely-tuned machines, they're completely chaotic messes of gas and plasma that are forced into their current shape by the fact that even the ridiculously high energy fluctuations of a stellar core can't get over the energy barrier to a different state.
So to really, significantly change what a star looks like is going to require energy levels and/or mass at least on the same order of magnitude as the stellar output. Even Jupiter is only 1/1000 of the Sun's mass; you'd either need something far larger than Jupiter using gravity, or you'd need an accelerator that had solar-levels of energy inputs.
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2019-12-11, 04:39 AM (ISO 8601)
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2019-12-11, 11:01 AM (ISO 8601)
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Re: Destroying a star
Exploding stars turn into an enormous cloud of gas that expands and becomes thinner as it spreads out until it's barely detectable. The core of the star remains behind as either a white dwarf, neutron star, or black hole, depending on how much mass it has.
When the star explodes in a supernova, it also converts a significant amount of mass into pure energy in the form of an extremely bright flash of light.We are not standing on the shoulders of giants, but on very tall tower of other dwarves.
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