One beast that I have wondered about is the big asteroid-dwelling worm that the Millenium Falcon encounters in 'The Empire Strikes Back' - what it's made of, what it lives on, how it survives in space and so on. A little online digging soon told me that it's called a 'space slug' or 'exogorth' and that it's a silicon-based gastropod (I'm pleading poetic license and sticking with 'entomology' rather than 'conchology' though), feeding mainly by metabolising asteroid minerals through its root-like tail and absorbing stellar energy, though not averse to eating the occasional spacecraft or other unwary space-dwelling creatures. Also, it apparently reproduces by fission, moulting as it grows, then simply splitting in two when large enough.
|The exogorth - in space, no-one can hear you roar!|
Firstly, the metabolising of rocks and their constituent minerals. It's well known that some bacteria (lithoautotrophs) can metabolise a variety of minerals such as sulphur, iron and manganese and are involved in both the creation of limestone cave systems (speleogenesis), and the phenomenon of acid mine drainage (AMD), the outflow of acidic water from metal and coal mines. The biochemistry of such acidophilic bacteria can be complex, but in the case of cave systems such as Carlsbad and Lechuguilla in the US, rocks have been attacked microbially in three ways:
- Oil-metabolisers - their biochemistry produces hydrogen sulphide which in turn produces sulphuric acid.
- Rock-eating bacteria - the lithoautotrophs directly metabolising minerals.
- 'Snotites' - large bacterial colonies which are primary producers in such ecosystems and drip sulphuric acid.
|A heap of chemosynthetic vent mussels.|
So, parallels between exogorths and real-world organisms? For molluscs, nutritionally yes but reproductively no - but what about the whole 'surviving in a vacuum' issue? Well, I think I'll leave that for Episode III...