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I have watched this movie Battleship. In it the researchers say this piece of metal is alien because we cant find this metal on earth.
So that would mean somewhere else in the universe any of the following should be true?

  1. Atoms' composition is not similar to that as on earth (nucleus, electrons, anything else)
  2. Elements with atomic numbers above 120 or 130 are stable (highly impossible without point 1)
  3. The realm itself is observed by different binding forces (but then, once that elements realm has changed, it should become unstable and collapse)
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You have answered it yourself, as not possible. It is real fiction, this science fiction you refer to. On the other hand did they talk about the atomic structure of the metal? It might have been an alloy that we have not yet thought to construct. – anna v Apr 24 '12 at 3:30
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Technically positronium and the other -oniums are elements, and they don't exactly exist on Earth. And they're not made of neutrons/etc. – Manishearth♦ Apr 24 '12 at 3:40
@Manishearth There are a lot of elements in the periodic table that are unstable and last only as long as the experiments. Every now and then a new element is announced, but by being not stable a metalic object cannot be constructed from them for long enough to reach another stellar civilization. – anna v Apr 24 '12 at 4:05
@annav: Exactly. What about supersymmetry? That fits the bill of the question (not sure about stability issues--IIRC the superpartners don't have known properties) – Manishearth♦ Apr 24 '12 at 4:06
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@anna v Aren't there even some organic metals that don't have any metal atoms in them? So it doesn't even have to be an alloy, it could be anything. Maybe some cool graphene-sandwiched-between-something-else meta-material – Lagerbaer Apr 24 '12 at 4:33
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In fact, some nuclear theorists do believe that there will be relatively stable heavy elements, as per your point 2. The so-called Island of Stability is predicted to occur because stability is maximized at certain so-called magic numbers which correspond to especially stable isotopes when the number of protons and/or neutrons matches one of the numbers. In particular, Z=114, 120, and 126 may have long-lived isotopes. These haven't yet been produced because it's difficult to get to the requisite number of neutrons to achieve a stable nucleus.

I should emphasize that this is just a hypothesis with essentially no experimental evidence at the moment. It is, as far as I know, a fairly active area of research. It almost sounds like crackpot science, but it definitely isn't and has a number of notable physicists and chemists connected to the hypothesis.

It is nonobvious whether these would be metals, though. If all you want is exotic metals, you'll have a much easier time just making compounds that haven't been synthesized on earth.

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They will be metals. There is no other possibility. – Anixx Apr 24 '12 at 12:42
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I don't think that's as obvious as you are claiming. As far as I know, most high atomic number elements that have been synthesized have been in small quantities, so that we can't really study their bulk properties. Cn is known to be a metal, but other elements with Z>108 are not known. One can try to use theory to predict that these elements should have the properties of metals, but in the particular regime nuclear chemistry becomes increasingly important to consider and results from condensed matter theory are questionable without experimental demonstration. – Logan Maingi Apr 24 '12 at 13:18
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I don't really understand why you claim there is no other possibility (unless you are an astronomer, because then of course they are metals by your definition). Perhaps you are claiming that these high-Z elements certainly would not have the properties of any known nonmetals, which I agree with, but it isn't at all obvious to me that they should be similar to known metals either. I decided to change dubious to unobvious, because that's more what my sentiment is, but I definitely don't think it's obvious. – Logan Maingi Apr 24 '12 at 13:21
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@LoganMaingi, there is nothing hypothetical in the island of stability hypothesis, because there is a measured increase of lifetimes for heavy elements after $Z>108$. Also, very far in the ultra heavy nucleus limit, we have neutron stars, which are effectively stable heavy nucleus, and we have ample evidence these exist, great answer. +1 – lurscher Apr 24 '12 at 17:20
@lurscher: Neutron stars are bound by entirely different physics, namely gravity, from the strong interaction in nuclei. As such, I don't really like thinking of them as large atomic nuclei. As for whether or not the island of stability is hypothetical, I more meant that the idea that some particular nuclei will have extremely long half-lives, on the order of decades or longer, which would be necessary for applications.There are definitely confirmations that there is an island of stability, but exactly how stable the most stable nuclei are is still open as far as I know. – Logan Maingi Apr 24 '12 at 20:53
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Metallic hydrogen is a metal that's not found on earth (but may be present in Jupiter): http://en.wikipedia.org/wiki/Metallic_hydrogen

Wether it does anything but evaporating or burning at ambient temperatures and pressures (or whatever conditions those aliens encountered in this movie), I don't know.

Since metals a generally in the lower left corner of the periodic table, I see no other candidate except transuraniae.

Of course, the alien metal could be handwavium, a material traditionally used for filling up plot holes.

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Well, meteorite minerals like iridium and all aren't really found on Earth in appreciable quantities.

What you're looking for are exotic atoms. These certainly exist, but are too unstable. And, for certain exotic atoms like onia, atomic number isn't even defined.

The binding forces cannot be different since the coupling constants are...well... constant (not sure what string theory says about this--but the Standard Model keeps them constant).

One thing that I can think of are "satoms" (atominos?), made of sprotons, sneutrons, and selectrons. Or maybe some other superparticles. Supersymmetry predicts that each particle has a superpartner. These ought to exist in our universe, but we haven't detected any yet. They are a candidate for dark matter though.

I'm not too sure of how superparticle stability works, though. Seems like only one of them is stable. We could make an atom out of that, I guess. But it's electrically neutral, and probably very light. So there may or may not be sufficient force holding it together.

As @annav said, what you may be looking for is a new alloy or something. THis will be an "exotic metal", but will still be made of normal atoms.

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