Alien motives and human assumptions
Would We Even Be Edible?
Compatibility is not the default. It is an extraordinary coincidence that terrestrial life mostly shares.
Plausible ExtrapolationTwo biospheres with no common ancestor have no reason to be food for one another.
What we actually know
All known life uses the same handful of conventions: DNA or RNA heredity, a shared genetic code, a specific set of amino acids, a particular chirality. Those conventions are almost certainly frozen accidents of one origin event, not requirements of chemistry.
Where the extrapolation begins
An independently evolved biochemistry could use different chirality, different solvents, different information carriers. It would not be nutritious, digestible, or even reliably toxic — it might simply be inert. Interstellar predation as a plot device requires a shared metabolism nobody has any reason to expect.
What the novel invents
The novel's biologists spend more time on this than the soldiers do, and reach a conclusion the soldiers find useless: whatever the object is interested in, it is not lunch.
Questions to think about
- — Why is shared chirality evidence of common ancestry rather than of chemical necessity?
- — If alien biology were inert to us, what risks would remain?
- — Does incompatibility make contact safer, or only differently dangerous?
Where to read next
- — Astrobiology literature on alternative biochemistries and homochirality
- — NASA Astrobiology — definitions and assumptions about life
Continue in the archive