I was reading about the rogue planet PSO J318.5-22 which is thought to have molten iron rain and things like that, and I vaguely remembered from uni that almost all iron mixtures have a slushy eutectic phase.

So I got to thinking, could you have life based on the impurities and crystal structures in that phase, with iron as the solvent? Different crystal systems can seed each other and self-replicate that way, different metals and metal complexes have various catalytic properties, and so on.

I don't plan on mapping out the details of that kind of biology, just want an opinion on whether or not it's vaguely plausible.

  • $\begingroup$ Relevant: Life on a molten world. $\endgroup$
    – Frostfyre
    Nov 2, 2015 at 17:23
  • $\begingroup$ Wouldn't such life form be more likely to exist inside a planet with iron-nickel core than on the surface of some exotic high temperature planet? "Plan 9 from inner space" with the aliens in their powered pressure suit digging up from below us to conquer our world and steal our women... oh wait, that wouldn't be a problem. $\endgroup$ Nov 2, 2015 at 17:58
  • $\begingroup$ @VilleNiemi: Inside a planet there is only this hot inside of the planet. On a surface there is hot inside and cold space (and hotter star if we are not on a rogue planet). Life needs not only energy, but also low entropy, for example difference of temperatures. $\endgroup$
    – BartekChom
    Nov 2, 2015 at 22:07
  • $\begingroup$ @BartekChom Obviously, but life usually relies on entropy differences between chemical compounds, not temperatures. Don't see why that would change. $\endgroup$ Nov 3, 2015 at 8:33
  • $\begingroup$ @VilleNiemi Most life on Earth lives thanks to the difference of temperatures between the Sun and space (or, more directly, thanks to the non-uniformness of radiation around Earth). Only near hydrotermal vents (and maybe deep in rocks) life uses chemical inequilibrium (which, if I understand correctly, is itself caused by the warmth of the inside of the Earth). What would cause chemical inequilibrium inside a planet? $\endgroup$
    – BartekChom
    Nov 3, 2015 at 8:49

1 Answer 1


Vaguely? Erm. Yes, but to paraphrase a certain pointy eared gentleman, it wouldn't be life as we know it, and as such I'm not sure we can extend the logic much further.

If (and this is a big if) you can create a high energy structure based around some of the heavier elements and their compounds, capable of self replicating, all in a ball of compounds with ridiculously high melting points, then yes. You can have life. It might even evolve, although according to what kinds of pressures I've got no idea. This species would have to be aquatic (for want of a better phrase) because it will likely sink under all the lighter elements that make up it's world, and it will have to be resilient beyond belief. By resilient I don't necessarily mean hardy, I mean hard to destroy. The creature will have to be able to take repeated poundings as local temperature variations and pressure changes change what phase of matter various parts of it's body are in.

Oh, and it's going to have to be fairly slow. Despite being in a high energy environment this creature isn't going to be able to think, particularly, so it'll probably resemble a superheated jellyfish or sponge.

Or worse. Fire-mold.

  • $\begingroup$ Fire-mold! Love it... $\endgroup$
    – Tom
    Nov 7, 2015 at 15:50

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