Maybe this question doesn't belong here. It's about a hypothetical xenobiology imagined by a prominent scientist in a seminal work of popular science. So I dunno. Tell me to go away and I'll see if some other SE can help me.

I'll never forget the races Sagan made up in his book Cosmos. He gave descriptions of them in the form of excerpts from his imagined Encyclopedia Galactica, a compendium of all the races in the galaxy.

There was one term that never made sense to me: "4K-metal chelated". What does the "4K" part mean? Here is the context:

Civilization Type: 2.3 R
Society Code: 1H1, "We Who Became One".
Interstellar civilization, no planetary communities, 
  utilizes 1504 supergiants, OV, BV, AV stars and 
Civilization Age: 6.09 * 10^15 s.
First local initiated contact: 6.09 * 10^15 s ago.
Receipt first galactic nested code: 6.09 * 10^15 s ago.
Source civilization, neutrino channel.
Local Group polylogue.
Biology: C, H, O, Be, Fe, Ge, He. 4K metal-chelated 
  organic semiconductors, types various. Cryogenic 
  superconducting electrovores with neutron crystal 
  dense packing and modular starminers; polytaxic.

(By the way, if anyone knows what "Local Group polylogue" is supposed to mean, I care about that too.)

  • $\begingroup$ If you can't find an answer here, maybe the people from worldbuilding.stackexchange.com will be able to help $\endgroup$ Commented Oct 9, 2016 at 18:01
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    $\begingroup$ Never actually heard of it, sorry. $\endgroup$ Commented Oct 9, 2016 at 18:05
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    $\begingroup$ If you didn't get it already there's some of fictional terminology. Fortunately you don't ask about 2.3 R type ;) Still it's quite possible that "4K" was made up. $\endgroup$
    – Mithoron
    Commented Oct 9, 2016 at 19:44
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    $\begingroup$ Sounds suspiciously like 4 kelvin, i.e. the boiling point of liquid helium under atmospheric pressure, since it mentions cryogenic and superconducting in the next sentence. $\endgroup$ Commented Oct 9, 2016 at 20:50
  • $\begingroup$ @NicolauSakerNeto -- I think that's our answer. Helium is in that list of elements. $\endgroup$ Commented Oct 10, 2016 at 2:15

1 Answer 1


These guys are "cryogenic superconducting electrovores" who apparently have "no planetary communities" so my guess is that "4K" should probably be taken to mean "4 Kelvin" and "metal-chelated organic semiconductors" as that they are composed of various types of semiconductors whose molecules are organics chelated with a metallic ion. About the "Local Group polylogue" thing, it's probably fictional stuff like a sort of interstellar Commonwealth or something.


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