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Plausible cosmic event that could annihilate the earth

  1. Jul 1, 2013 #1
    I am writing a screenplay that hinges around the imminent destruction of the earth. Can somebody describe a scientifically plausible cosmic event that could obliterate the earth. The only criteria I need to fill is that it can be identified four years before it reaches us. My first thinking was an exploding star, but could that be identified as a threat four years before it actually effects us? I am not keen on the idea of an asteroid. I am looking for something that would totally obliterate us into dust. Any ideas?
    (It would be great if you could describe the event, but also how it could be discovered on earth by scientists).
     
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  3. Jul 1, 2013 #2

    mfb

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    A medium to large black hole is possible, and with a bit of speculation you can get only 4 years of warning time (we had some threads discussing that in the past). The earth would simply vanish in the black hole.

    A supernova... hmm. I think is not completely impossible to predict such an event, but it is hard to kill all life on the surface with that. 50% of the earth is always in the "shadow" when the initial radiation arrives.

    The big asteroid will not destroy earth completely, but it can make life on the surface impossible.
     
  4. Jul 1, 2013 #3
    If you're looking for a non-asteroid way of ending all life on Earth -grey goo, bioweapons, or just plain old nukes would do the trick. If you're looking for something more science fiction (but still plausible) then asteroids are the simplest - there really aren't that many ways to cause that serious a change to a planet. We've had near-misses by several asteroids in the past year - if a massive one at high speed hits the moon, not the Earth, then there are a number of ways it could make life on Earth difficult for decades or centuries - either by bombardment of particles, or altered orbit, or even by ejecting enough material from the moon to reduce the amount of sunlight that can reach the surface of the planet.

    There's also plenty of other man-made causes that could sterilize the planet. Remember STUXnet? If a beefier version of it got out, geared to send reactors into meltdown, and robust enough to spread like informational wildfire, there'd be nothing left on the surface more advanced than cockroaches within a generation. Enough "dirty" bombs would accomplish the same purpose. "White Plague" was a story of bioweapons gone wrong.
     
  5. Jul 1, 2013 #4
    You could start an issue with the sun. four year period resulting in extraordinary mass expulsion pointed at the earth. it could be caused by the interaction with a "white hole" (here to unknown but evidenced by an area of high energy particles that seem to destabilize gravity).

    as a writer it is your universe. make it fit your story. just enough detail (no math :) ) to sale the idea.
     
    Last edited: Jul 1, 2013
  6. Jul 2, 2013 #5
    Thanks for the responses.
    The reason I am asking you guys about this and not just creating my own total fiction, is that I think the best science fiction is only one or two steps away from truth.
    I like the idea of the sun destabilising. But it's still a bit local for my liking.
    This has to be something beyond the control of humans. So bombs and human stupidity are out.
    I also want total obliteration, sterilising the planet isn't quite enough :)

    How about this:
    in a cluster of 20 or more stars, one dies and explodes. This forces out 2 of the nearest stars which begin to orbit each other. These two stars pick up speed, and as they pass by the other stars in this cluster, they pull along up to 15 more stars. This entire group of stars then steak through our solar system destroying every planet and the sun.

    Could someone describe this situation in a believable way? Using authentic scientific jargon.
    Is there a real cluster of stars anywhere near our solar system where this might happen?
    If these stars were orbiting each other, could they accelerate? Up to almost the speed of light?
    What methods would we have on earth that could detect this? If this is impossible, can anyone imagine a device or method that is currently beyond our current technology, but still sounds plausible?
    Would a planet that was swallowed by a star explode or vaporise/melt? would rocky planets and gas planets react differently?

    The biggest problem I have with this idea is the speed of light. How could we detect something traveling towards us at the speed of light (or close to), and still have a 4 year warning?

    Thanks for your input everyone!
     
  7. Jul 2, 2013 #6

    phyzguy

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    The problem with your star cluster scenario is that stars just don't move fast enough. Even at speeds of 1000's of km/sec, we would see them coming hundreds or thousands of years before they arrived. I think you need a dark body so you don't see it until four years before it arrives.

    How about a large asteroid or small planet that plunges into the sun, heating it up to the point that the Earth becomes uninhabitable?

    The supernova idea could work. We could discover a faint, nearby star that suddenly flares up due to interaction with some other star, and we realize that it will go supernova in a few years. I think mfb's objection is not valid - the radiation from supernovae lasts for weeks, so all part so fthe Earth could be sterilized.
     
  8. Jul 2, 2013 #7

    Bandersnatch

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    Sorry, proggprod, that's a rather unlikely scenario.
    IIRC, fastest peculiar(i.e. not related to orbital movement)velocities of individual stars in the galaxy are in the vicinity of a hundred kilometres per second. Moving at any sort of appreciable fraction of light speed is out of the question.

    There are no nearby clusters of stars. As mentioned before, relatively slow velocities mean that it would take thousands of years to travel just the distance between the Sun and Alpha Centauri(4,5ly).
    The nearest are Hyades, at 150 ly.

    The mechanism for inducing velocities that you've proposed, is implausible as well.
    Additionally, even if the Sun passed through a cluster, the event would not cause its destruction. At worst it would eject the planets into interstellar space.


    The major problem with the possible scenarios is your insistence on "total destruction". It's surprisingly hard to destroy a planet. For example, the Earth will probably survive the Sun exploding in a few billion years.


    The closest to it would be probably a collision with a large planetoid, so that the surface of our planet ends up molten or heavily volcanic. But I don't see any sensibly plausible way to actually vaporise the Earth.


    If sterilisation is, after all, going to be acceptable, then I'd go for a nearby supernova. Betelgeuse is, for example, kinda sorta looking as if it was soon(in astronomical terms) to collapse. With a bit of stretching the reality, it could serve as the doomsday machine(make it enter the last stages of life now; pretend it's close enough to affect us; maybe make it rotate poles-on as seen from Earth, so that the gamma ray burst hits our planet; make it last long enough to catch all of Earth's surface). The actual state of the star is uncertain enough that you could simply go with better instruments allowing us to see the danger.
     
  9. Jul 2, 2013 #8
    The goal of fiction is to take us where we have not been. Take Steven Kings _Dome_. Not very plausible in a physics class but seems real in King's book. the disaster could come from an accidental intrusion of another multiverse. all you need is some way to disrupt local gravity.

    maybe the multiverse has leaned how to mine other universes for something they need :)
     
  10. Jul 2, 2013 #9

    mfb

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    As far as I know, recent calculations indicate that the earth will probably fall into sun. Mars can survive it.


    Hmm... I found some supernova lightcurves.
    1040 erg/s X-rays for ~100 days.
    -19mag brightness for a few days.
    -19mag brightness for a few days.

    The visible light does not help, however. Absolute -19mag in a distance of 10 pc (too close to stay undetected until now, if the star is massive enough for a supernova) gives apparent -19mag. Brighter than the moon, but still not enough to give dangerous effects.
    I am not so sure about the x-rays.

    Anyway, it could just kill some life on the surface.


    There is no way to make anything like this plausible, unless you introduce aliens with magic.

    If it starts very far away... yes.

    It would evaporate inside the star. Unless you have a really freaking dense planet (nearly 6 times the density of lead).


    What about small black holes? I think they look like a perfect solution.
     
  11. Jul 2, 2013 #10
  12. Jul 2, 2013 #11

    phyzguy

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    I agree that an ordinary supernova won't do it. Anything massive enough to supernova would be visible from far away, and I don't think we know of anything close enough to be dangerous. Even Betelgeuse if (when!) it goes off will probably not be dangerous. However, I was thinking about some dark remnant, like a dead neutron star, that interacts with a dark companion and then becomes massive enough to supernova. It could be nearby, maybe within a few light-years. If there were two dead neutron stars orbiting each other a few lightyears away that finally got close enough to start merging, that could do it. We migh get a few year's warning if they started interacting before they finally merged.
     
  13. Jul 2, 2013 #12

    Ryan_m_b

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    May I ask why you want the earth totally destroyed? Sufficient damage to the biosphere could easily wipe out all human life long before life itself was extinguished on earth.
     
  14. Jul 2, 2013 #13

    mfb

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    Really cold neutron stars? Hmm.
    It would be interesting to check if gravitational wave detectors are sensitive enough, but I guess that is not an issue for science fiction. Maybe there is even a direction where orbiting stars do not emit gravitational waves (?).
     
  15. Aug 13, 2013 #14

    DHF

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    Main sequence stars coming our way would normally be easy to see coming more then 4 years away because as others have mentioned, they don't move fast enough to be speeding bullets in the cosmic sense.

    However what about Black Dwarf stars? After a star such as ours dies it puffs up into a red giant then eventually cools into a white dwarf, a cooling ember of its former self. over time it will continue to cool until it no longer emits any light but it would be enormously dense comparatively to planets or asteroids.

    Theoretically Black Dwarfs can exist but none have been confirmed because the math suggests the universe is not yet old enough for any white dwarfs to have cooled to that point......theoretically. The beauty of sci-fi is that you can bend the math a bit. we just haven't spotted any yet, we THINK none exist yet but what if they do? IF Black dwarfs Were out there and were on a collision course it would be very hard to spot because they are all but invisible, they admit no light so we could only detect them by their gravity. It is conceivable that we might not spot one until it was on our door step. If we were unlucky enough for something like that to be on a collision course with Earth we would be shredded. Even if it didn't smash it us but only grazed by us, the gravitational pull would destabilize our orbit and all sorts of unhappiness would ensue. Maybe it yanks us out of orbit, flings us around and tosses us into our own sun. who knows, its up to you.

    Granted its similar to an asteroid impact but a lot more exotic because hey its a star corpse!
     
    Last edited: Aug 13, 2013
  16. Aug 15, 2013 #15

    chemisttree

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    Still interested in this? If so, I've got what I believe to be a plausible killer. It won't explode the Earth but it will strip the atmosphere and sterilize.
     
  17. Aug 16, 2013 #16

    DHF

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    The suspense is killing me Chemisttree, what is your idea??? :)
     
  18. Aug 29, 2013 #17

    chemisttree

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    It's something close... well, closer than you might think.
     
    Last edited: Aug 29, 2013
  19. Aug 29, 2013 #18

    Vanadium 50

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    The problem with anything star-sized/massed is that it will perturb the planetary orbits once it gets within a few tens of billion miles of the sun. That means its moving above galactic escape velocity, so the question of how it got there in the first place opens up.

    Does it have to be astronomical? How about geological - a supervolcano 100x larger than Lava Creek.
     
  20. Aug 30, 2013 #19

    mfb

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    Hypervelocity stars that will leave our galaxy exist - binary systems where one partner exploded and 3-body mechanics are possible sources.
     
  21. Sep 10, 2013 #20
    A meteorite destabilizing the moon would probably get rid of earth.
    L.H.C. might create a small black hole.
    I think the collision of solar system/earth/sun with a hitherto invisible black hole could be plausible...
     
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