What single element could destroy the world?

Some of the answers seem to be - while amusing - either 100% wrong (the proposed method wouldn't destroy ALL life), or outside the question's clearly delineated parameters (e.g. near future means, no magi-tech, no hand-wavium)

  • Hydrogen atom. 20 upvotes. Requires magi-tech to accelerate the atom to needed energy, clearly NOT feasuble with near future means.

  • Neutron star. 10 upvotes. Leaving aside requiring magi-tech to acquire one, the question explicitly mentioned periodic table of elements, so no amount of "looks like an atom" hand-waving can make it be an on-topic answer.

2 answers have serious flaws but at least are fixable. My question really is about 2 answers above, not the following.

  • Astatine. 3 votes. While nowhere near as bad as other answers, it doesn't even remotely show that it can be used to wipe out all life - as opposed to a couple of beings. Mind you, this answer can probably be improved to show "how", so it's the 2-d least objectionable one.

  • Hydrogen explosion - this one has only one problem. It wouldn't affect life on deep sea floor. (though, with enough hydrogen, maybe? That requires some calculations to be sure; as well as knowing how much Oxygen you have available).

  • 4
    $\begingroup$ Just to clarify - my grumpiness with magi-tech answer is in no way related to my attempt to use this question for practical applications. $\endgroup$
    – user4239
    Commented Jun 3, 2015 at 15:02
  • $\begingroup$ To be fair I did add or at least clarify some of the requirements late. I assumed perhaps incorrectly that the hard-science tag would indicate I wanted a somewhat realistic solution that while insane and challenging is at least possible. $\endgroup$
    – James
    Commented Jun 3, 2015 at 15:25
  • $\begingroup$ I have also relaxed the killing to vertebrates...all life seems to be too much. Though I agree that things have been a little off the mark...I am not sure if that is due to the question not being clear enough, or maybe my understanding of the tag I used. $\endgroup$
    – James
    Commented Jun 3, 2015 at 15:27
  • $\begingroup$ We see a lot of that in here WB. Happens most users are not scientists and I dare to say some has not a science background $\endgroup$
    – jean
    Commented May 8, 2018 at 12:24

6 Answers 6


People upvote answers because they are clever, witty and entertaining, even if they are clearly outside the scope of Worldbuilding. Worldbuilding is generally about coming up with fictional worlds which if not realistic are at least plausible.

In the linked question, accelerating a single proton to sufficient energies to disintegrate a planet is completely implausible and integrating it into a fictional work would require some serious handwavium, considering the most energetic particle ever detected, 10 million times more energetic than anything we can create with our most advanced accelerators, hit with the energy of a baseball travelling at 55mph. The energies involved in that answer at least would only take about 1 week output of a dyson sphere, magnitudes less energy, than say steering a neutron star into the Earth.

What these answers have in common, is they are clever and entertaining, they answer the title of the question, and basically disregard the text of the question. For example in the linked question, even in the original version of the question it specified "chemical element, get out your periodic table" (last time I checked, Neutron Star is not on the periodic table), and that this was to be done by a "mad scientist", not a wizard or a civilization with extreme hypertechnology. Neither of the top voted answers are answers even to the original question - let alone the revised versions.

I think one of the things people like about Worldbuilding is that making stuff up is generally permissible. If someone asks a question on Space which is too speculative (i.e. cannot be given a scientifically sound answer), they might be told to ask it on Worldbuilding instead, because on Worldbuilding speculation is welcome and answers don't have to be scientifically sound. It is a site where people can have fun, and maybe it becomes about having fun, but this could easily degrade the usefulness of the site if poor answers are consistently upvoted (yes, I'm sure some people ask questions in the hope of getting entertaining answers, but I'd hope some people ask questions because they are making a fictional world, for a novel, game or so on).

Answers should actually attempt to answer the question as a whole - not merely answering the title taken completely out of context. Furthermore, plausibility in general should be valued, unless the question indicates that it is a fantasy world with high magic or hypertech.

  • $\begingroup$ Technically, neutrons are element zero, and a neutron star is a single atom of that element. $\endgroup$
    – o11c
    Commented Jul 16, 2015 at 20:39
  • $\begingroup$ @o11c That is a tidy fiction, look it up, at present we don't know exactly what neutron stars are made of, but it is theorized they have an outer crust of mostly atomic nuclei, with the core being neutron degenerate matter but it could also be strange/quark matter. What it is not is a big tidy ball of neutrons as found in ordinary atomic nuclei - sure there's probably lots of neutrons in a neutron star, but also enough protons to give it an atomic number comparable to Earth or Jupiter. $\endgroup$ Commented Jul 17, 2015 at 7:51
  • $\begingroup$ @o11c No they are not. Someone asked that (in Astronomy SE I guess) and was promptly rebuffed. $\endgroup$
    – jean
    Commented May 8, 2018 at 12:22

I can't speak about the other answers, but my answer was probably upvoted because, at the time I answered, there was nothing in the question about using near-future technology. The goal of the question was to 'destroy the Earth, or at least obliterate all life, using only one element.'

I've seen this happen in a few other questions as well, where the asker wants different answers than what are provided, and changes the question to try to get them. Unfortunately, this means that what were previously good, relevant answers no longer make sense in the context of the edits to the original question.

  • $\begingroup$ Yep, I alluded to this in my second point. People ask broad questions, then the answers help them to define what they actually want. The real problem is that the 'good, relevant answers' are still good, they're just no longer relevant. $\endgroup$ Commented Jun 3, 2015 at 19:04
  • 3
    $\begingroup$ If the question is too broad for a reasonably sized set of answers, then the question should be put on hold as too broad. Hash out in the comments or in chat what the OP is after (chat if possible), get the question clarified and reopened, and then answer the question. If the OP wants to add constraints after the fact, that should be in a new question. Answer-invalidating question edits should be candidates for rolling back, and asking the OP to take them to a new question instead. There is nothing wrong with asking follow-up questions with different acceptance critieria. @DaaaahWhoosh $\endgroup$
    – user
    Commented Jun 4, 2015 at 9:16
  • $\begingroup$ Even the original version of my question without edits should have made it clear that I wanted something feasible. I used the hard science tag and mentioned that I was having a mad scientist do this, and while yes your answer was scientifically sound it clearly didn't meet the, 'executable' by a mad scientist requirement. $\endgroup$
    – James
    Commented Jun 8, 2015 at 18:01
  • $\begingroup$ hard-science may be the wrong tag choice in this case. It specifies that "all answers to this question should be backed up by equations, empirical evidence, scientific papers, other citations". The best tag for things that are achievable with known science and technology is probably near-future, which seems applicable to your question. $\endgroup$
    – ckersch
    Commented Jun 8, 2015 at 19:11
  • $\begingroup$ Yeah, both tags may have been the best solution. $\endgroup$
    – James
    Commented Jun 9, 2015 at 14:10

I think part of this issue comes from mob mentality, which causes people to behave in accordance with the people around them. Seeing a question or answer that already has upvotes implies it has good content, which encourages people to upvote it again.

I know that I, while reading through the existing answers to a question, sometimes forget parts of the question, which leads me to wrong conclusions about the validity of an answer. I doubt I'm the only one. If someone remembers the question wanted an element to destroy life on Earth, but didn't remember it needed to be done with near-future technology, the hydrogen answer (voted +26/-2 at the time of this writing) appears to satisfy the question.

Also, remember that there is no specific reason a person is required to vote. You are not required to explain why you voted (or didn't vote), nor should you.

Personally, I didn't vote on those answers, mostly because I don't often vote, but also because the answers at the time didn't satisfy the question.


The reason is very simple in fact:

  • The content in worldbuilding, as long as it fascinates people with the possibilities that such a thing might exist, is prone to be supported faster;
  • If the answer has some coherent logic (although totally impractical or close to reality), changes the reader's perception in accepting the concept;
  • Mob upvoting as Frostfyre mentioned encourages more people to read and subsequently upvote;
  • If a fictional concept is largely supported, new concepts may arise from it, thus expanding and turning the original one into a largely accepted and popular concept;
  • Finally, it's much harder to delete an already popular/accepted concept.
  • $\begingroup$ I'll only disagree on the last point there: all that having upvotes means is that 4K users can't delete it. If it's bad, 6 Recommend Deletion votes or one mod vote can still delete it. $\endgroup$
    – ArtOfCode
    Commented Jun 6, 2015 at 14:14
  • $\begingroup$ @ArtOfCode I didn't know that, but wouldn't it be hard, even for a mod with the permissions to do so, to erase so many people's opinions at once? I was not directly mentioning the answer itself... Thanks for the vote btw :) $\endgroup$
    – Armfoot
    Commented Jun 6, 2015 at 14:22
  • $\begingroup$ A mod can just hit the "delete" button and poof it's gone. Their decisions are subject to community appeal, but mod-deleted answers can't be undeleted by 4K users, so if all 3 mods agree it should be deleted it's going to stay that way. $\endgroup$
    – ArtOfCode
    Commented Jun 6, 2015 at 14:24
  • $\begingroup$ @ArtOfCode I see... Being a moderator is a very demanding task everywhere, here is no exception it seems. At the end of the day the amount of people that get frustrated with those decisions may be the same or greater to the ones that benefited from it. Without them though, there would be chaos and the big ones would relentlessly prey on the rest... (I probably read this somewhere...) $\endgroup$
    – Armfoot
    Commented Jun 6, 2015 at 14:41

There's a strong preference on WorldBuilding for positive answers. I think this is a side effect of the creative nature of the SE. We don't always know what is going on in the OP's head. It is far more helpful to provide a person some clever-yet-absurd solution which may knock free something in their head that creates brilliance than it is to simply state "you cannot do that."

We could easily have closed a series of 4 or 5 questions as "impossible" or "too broad" because, honestly, life has had a vested interest in not being annihilated. This not only covers being annihilated by a single element, as per the question, which is a cakewalk compared to the more complicated things life has to protect itself again. It would take quite a lot of discussion to arrive at this hard reality for the OP.

Accordingly, we switch to creative/loophole approaches to try to jar loose some thinking on the OP's part. The absurdity of the answers points at the directions the OP should look at next.

It would be interesting to set up a policy as @Michael Kjörling calls for of putting the question on hold and bringing it into chat. However, the format of SE does not seem to make that easy. We almost need a two phase approach where an open question is first communally edited for answerability, and only the answered. It would also end up being a very subjective approach. I'd say easily 70-90% of the questions I see here are questions I think would benefit from some back and forth discussion before the official question/answer pattern is used.


I kind of think that good answers should be upvoted regardless of whether or not they answer the question. If it's a good read and teaches me things that I find useful (like how a neutron star might be considered a single atom), then I'm going to upvote that so that other people will see it. Of course, if it's way off-topic, then no one who needs to see it will probably ever see it, so that should be downvoted and/or deleted. However, someone looking for an answer to a similar question may find these answers useful.

Plus, at least on Worldbuilding, it seems that a lot of questions don't exactly know what they want. I think one of the problems we have here is that many of our questions are too broad, but when they get narrowed down there is no room for the best answers. If you have to bend the rules to answer, I think it may be worth it to try; not that we should encourage this sort of behavior, but I think it all works out in the end (people wouldn't upvote if they were unhappy).

  • $\begingroup$ With all respect in the world, no matter how well an answer is written, if it is wrong it is not a good answer. When Joshua Hanley pointed out an error beyond repair in one of my answers i removed it promptly without regards of the upvotes. $\endgroup$ Commented Jun 4, 2015 at 8:06
  • 2
    $\begingroup$ An answer that does not answer the question is not an answer. It should be flagged, downvoted and possibly deleted; absolutely not upvoted. Answer usefulness should be judged in relation to the question they are attached to. $\endgroup$
    – user
    Commented Jun 4, 2015 at 9:20
  • $\begingroup$ @MichaelKjörling It just seems like a waste to me to downvote or delete an answer that is well-thought-out and generally useful. Just because the OP decides it's not useful to them doesn't mean someone else won't get something out of it. I know this isn't how SE generally works, but we've often shown that WB is different. $\endgroup$ Commented Jun 4, 2015 at 13:04
  • 1
    $\begingroup$ This isn't how SE generally works. This is how SE actually works. It is the core principle of the site. Answers to Questions. Worldbuilding is lax compared to most on the kind of questions, but the core principle remains the same. We are not wikipedia, where information is stored, we are SE, where questions are answered. $\endgroup$
    – Mourdos
    Commented Jun 6, 2015 at 15:01

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