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Physically plausible explanation for artificial supernova!

  1. Jul 3, 2014 #1
    Hi,

    What would be a plausible explanation for the induced supernova of a star? (Or at least an explanation that had a shot at being plausible!)

    What about a large antimatter explosion in the star's core, perhaps deposited there through a small wormhole?

    Or could some kind of missile be used? I'd imagine it would have to be vastly powerful, maybe iron-based? Or using antimatter?

    Or is there some other creative way of doing it? This would preferably be to induce a near instantaneous explosion. I think they explode at 10% the speed of light, so you would just have to travel faster than that to escape the shockwave.

    Many thanks for any replies!
    :tongue:
     
  2. jcsd
  3. Jul 4, 2014 #2

    Bandersnatch

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    Explosions won't do. The star would at best swell up a bit to maintain equilibrium, and then quickly revert back to the original state. At worst it wouldn't even notice - Tsar Bomba, the largest device ever detonated, had output equal to one billionth of the energy the Sun produces in one second.

    The only way I'm aware of, is to dump enough mass onto a star in the form of heavy elements(neighbourhood of nickel/iron, to prevent fusion) to cause the core to collapse. You could also try dumping mass(can be even hydrogen) onto a white dwarf, to induce a type Ia supernova.

    In any case, you'd need an absurd amount of mass. But since you have wormholes at your disposal, maybe use it to siphon some distant star's atmosphere onto a white dwarf? I can't imagine this being a quick process, though.
     
  4. Jul 4, 2014 #3
    Actually I think he may be onto something here. Type Ia supernova ignition starts in the center of critical mass white dwarf: a slight local heating triggers thermonuclear burn.

    If nuke would somehow be exploded in the core of slightly subcritical (by mass) white dwarf, it probably *can* trigger the burn.

    This is about as plausible scenario as you can get. I have no plausible ideas how to transport the nuke to the core :/
     
  5. Jul 4, 2014 #4
    Thanks for the reply!

    So how does the thermonuclear burn work, I've read about a 'thermonuclear cascade' before? I'm guessing that's the big burst of radiation that sweeps outward in a shockwave.

    Any idea how big the explosion would have to be to trigger the reignition of nuclear fusion?
     
  6. Jul 4, 2014 #5
    Thanks for the reply, v. interesting.

    Yeah one of the issues is the timescale. So the two options are detonating a nuke at the centre to reignite nuclear fusion in the star, or inject a large mass of iron to cause gravitational collapse.

    Crazy idea, but what would happen if one used a wormhole to transport an entire star into the core, for example Proxima Centauri into the sun? :tongue:
     
  7. Jul 10, 2014 #6
    Since I've also wondered about using this in a story, just how much mass would be needed for tipping a white dwarf past that point?
     
  8. Jul 10, 2014 #7

    Bandersnatch

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    Depends on the mass of the progenitor white dwarf. It explodes at about 1.4 solar masses. So, if you start with a 0.6 solar masses white dwarf(the typical mass), you'd need almost a Sun's worth of extra mass to dump on it.
    That's why type Ia supernovae happen only in binary systems, where the companion star enters a supergiant phase, and starts losing its outer layers to the white dwarf.(or when two white dwarfs merge)

    This particular star would probably just make the Sun brighter and larger. I suspect a very old red dwarf, composed mostly of helium, could change the core composition enough to trigger red giant phase. But I don't won't to make any definite statements, as I don't understand the physics enough.
     
  9. Nov 20, 2014 #8

    DHF

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    Since this is for a Story you are writing I think the first thing we need to understand is the "why". Why are your characters attempting to trigger a supernova? what do they hope to gain from it? are they using it as a weapon or some other benign purpose?

    The reason its important to understand this is because what you want to accomplish will require an insane amount of energy. Either making a powerful enough explosive or opening up a wormhole and dumping mass, you are talking about characters that have access to godlike amounts of power and technology and in the end it would probably take more energy to accomplish the task then they would get out of the supernova. Therefore there has to be some goal in mind that makes it worth the expenditure.

    Give us some details and maybe we can work something out that is plausible.
     
  10. Nov 25, 2014 #9
    If this is a weapon, the technology required can't be such that would render the weapon obsolete. I think wormholes would probably fall under that category, but I'm not sure. Wormholes are such a game-changer that it's hard to imagine the implications.
     
  11. Nov 26, 2014 #10
    http://en.wikipedia.org/wiki/Carbon_detonation

    Thermonuclear burn in detonating white dwarf of critical mass works just the same as in a hydrogen bomb. Fusion reactions in both cases are very temperature-dependent. When reaction rate is enough to cause noticeable heating, reaction enters a runaway loop: heating increases reaction rate, which in turn increases heating, and so on.

    In a H-bomb, this makes thermonuclear burn to consume all LiD fuel in 20 nanoseconds (regardless of the bomb size).
    In a detonating white dwarf, simulations show that detonation front from the center reaches star surface in something like 2 seconds.

    To trigger a slightly subcritical dwarf, you don't need a humongous big bomb. I am not sure, but it's possible you don't need a big bomb at all. All it needs to do is to sufficiently heat a small amount of star material so that fusion reactions in this material start to heat it more by themselves.

    The hard part is how to get the bomb into the star's core, but for sci-fi this should not be that hard :)
     
  12. Dec 6, 2014 #11
    I really like the antimatter idea. I'm not even sure you would have to get it to the core of the star. Just touching the surface should be good enough. If you don't mind me asking, why did you want to induce a supernova? If you want to use it as a weapon, obliterate a planet and kill all the inhabitants, then finesse really isn't a concern. If you want the debris after it cools down (and I assume loses much of its radiation), then I could see where it would very much matter how you blow your star upl
     
  13. Dec 6, 2014 #12
    In the movie Man of Steel General Zog decides he is going to turn Earth into the next Krypton by adding to its mass. The question I immediately had when I heard this scheme was: "Where is the extra mass going to be coming from?" Did they have the technology to open a wormhole at the center of the planet and import the mass from...elsewhere?

    The next question I had was: "Even if you could do this why would you bother? It's too damn much work." The Kryptonians have FTL, why not go out and find a planet of the proper mass to begin with and terraform that one? For the sake of argument say you had the technology to turn Antarctica into a tropical paradise. Say that you're so advanced you could do this quite easily. No matter how little work is involved to turn Antarctica into a tropical paradise it will always be less work to move to the tropics. General Zog doesn't have to be ethical to spare Earth, being indolent will more than get the job done.
     
  14. Dec 6, 2014 #13
    Absolutely not enough. Upper layers of white dwarf are not compressed (since there is no material above them). At least a few tens of topmost meters are not even a degenerate matter, it's ordinary matter, with ordinary densities, and with relatively low temperatures (below 100k Kelvins).

    The pressure and density, of course, quickly rises with depth, but pressure does start from zero at surface. The star is not a uniform ball with uniform conditions inside. The center is, by far, the densest location - the best place for triggering explosion.
     
    Last edited: Dec 6, 2014
  15. Dec 6, 2014 #14

    Ryan_m_b

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    Same, that film was terrible.

    Typical case of having an evil character do evil things....even when they make absolutely no sense. Aside from the fact that Earth seems to bestow god-like powers that take meer hours to acclimatise to why do they have to genocide a species by terraforming the planet? Terraform anywhere else!
     
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