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 pulsars. 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.)