Science of Star Wars: Aliens

Perhaps the best part of Star Wars is the ubiquity of life in the Universe.  Star Wars presents a broad scope of intelligent life across many different worlds – all living and interacting together.  Aliens are still science fiction.  But we know enough about science to have some thoughts about what life might look like.

Most likely, alien life will be bacterial. This shouldn’t be controversial; most life on earth is bacterial.  We even suspect there is bacterial life on other objects in our own solar system (Europa, Io, Enceladus) given how pervasive it is in extreme environments on earth.

But we’re talking about intelligent life here.  People walking around, walking and talking, writing blogs.  We know that human-like creatures can exist, because we exist.  What would these beings look like?  Would they be as “weird” as those we see in Star Wars?

The reality is they would probably look like us.  Why? How?

Copyright Lucasfilm

Well, if intelligent life (as we think of it) is the result of the environment of planets – water-based, mild temperatures, primarily aerobic, with brains fueled by sugar, then they probably all look somewhat like us.  Carbon-based (easy to construct organic objects using photosynthesis), two arms, two legs, large brains, efficient carbohydrate-based energy conversion.  The fossil record shows several species in addition to homosapiens who have followed this path.

Things like the amount of oxygen in an atmosphere can support different sizes of creatures.  The skeletons of long-extinct animals from time periods in earth’s history when there was more oxygen content in the air were often incredibly large.  The gravity on a planet may impact how tall an animal may be.  Atmospheric density matters too, though if it’s too thin, it may be insufficient for life (if it’s too hard to ingest oxygen then building a large brain is a no-go).  And, of course, your planet can’t be decimated too often by meteor impacts or environmental instability (see Venus).

All this also means that finding intelligent life might be more rare than Star Wars illustrates.  The book Rare Earth: Why Complex Life is Uncommon in the Universe(rather boringly) describes the possibility of life on other planets.  Essentially there are so many variables that have to take place for large animal life, let alone intelligent life, to emerge.  It’s hard, though not impossible.

So, Jabba the Hutt – probably out.  Chewbacca – maybe.  Greedo – perhaps.  Twilek’s – I hope so.  Ithorians… not so sure.