Walking the Planck

16 01 2012

One of the problems that you can run into as writer of science fiction,
especially if it involves other planets and civilizations is the problem
of units.  What I mean by units is how would a civilization that exists
in a different frame of reference measure things?

There are two solutions to this conundrum: (1) use Earth units and hope
no one notices or cares or (2) invent your own units and confuse
everyone (including yourself).

(1) This seems to be the most common among popular science fiction fare.
Perhaps there’s something to the correlation between ignoring units and
popularity.  We science fiction fans love to think, but not that much.
On a show like Star Trek where different aliens are introduced each week
it would become awfully difficult to provide each with their own units
of measurement.  And that is something that becomes more and more
unwieldy when you start examining what is required to invent your own
units of measurement.  Here are some good arguments for ignoring reality
for the sake of convenience:

(a) Writers know that the audience is suspending their disbelief
anyway.  Most fans of the work are not going to notice that Joe Alien
keeps referring to things in terms of hours or meters.

(b) Besides, most of the time the alien is speaking English anyway.  Must be that the person doing the translating (or the universal translator as used in Star Trek) is converting the units too.

(2) Inventing your own units can be fun if not confusing for the imbiber of your fiction.  There are two ways to go about this:

(a) Just make up a funny word and have your characters use it without ever explaining its significance.  For example, Battlestar Gallactica characters talking about centons and yahrens and such.

(b) Invent your own units and tie it to whatever you  like.  You could build your base unit of time around some quirk of the alien planet’s rotation.  Really there’s not much difference between making up your own system and just making up new terms because in most cases the reader/watcher can’t tell the difference.

As an example I’ll relate a anecdote about a recent story I wrote.  I thought it would be neat to have my new civilization measure distances based on light years.  As you know, a light year is the distance light travels in a year.  As you also know, light travels very quickly, so to measure a smaller distance you have to use prefixes such as “femto” or “nano”.  So I went merrily along using my nifty “femto” terminology.  Then I realized that I had been applying my new term all wrong.  Our idea of a light year is based upon the length of an Earth year.  If you were to measure light years using the length of a year on another planet, you would get a totally different distance!

This becomes even more unwieldy when you do something rash like making the aliens use an octal rather than a decimal system.  Talk about confusing yourself.  (Of course there was the added benefit of having an excuse to make a cool spreadsheet.)  In my story, I have the main human character learn the language of the alien civilization.  This seemed like a rather elegant solution on the surface because then I could write the story in English with the  reader understanding that the conversations were actually taking place in the other language.  But there was a snag.  When they needed to talk about distances and time, it seemed unlikely that my human was going to be able to make the conversions in his mind fast enough for normal conversation.  My solution: he couldn’t.  He did some of the easier calculations in his head, but there are times where there is a barrier of understanding where he admits that he can’t translate the units and goes about trying to explain it another way.  In other words, I am not expecting my character to do anything that I as a writer am not able to do.  Now I can pull up Excel and figure it out, but my character doesn’t have that luxury.

(c) I suppose that you could find a universal constant to base your measurements around.  That would make conversion between the two systems easier.  For example, you could use the Planck length as your base unit.  The Planck length is theorized to be the shortest possible distance and is arrived at using the speed of light in a vacuum, the gravitational constant and the Planck’s constant (this has to do with sizes of energy quanta in quantum mechanics).  The problem with this is that the Planck length is so incredibly small as to make its use as a basic unit cumbersome.  To get an idea of how small a Planck length is imagine a decimal point with 35 zeros behind it before you get to a non-zero real number.  Now, you could talk about yotta-Planck lengths but that would still leave you with 11 zeros behind your decimal to contend with.  Now you are back where you started from with (b); you have to make up prefix names to get the distance into a workable range.

The point of all of this is to keep it simple and not let details like this distract from the story.  If you must figure it all out, keep it to yourself and maybe someone will publish your spreadsheet posthumously like Tolkien’s son did with his Lord of the Rings mythos.  It will be interesting to nerds, but not required for the enjoyment of the main work.




One response

17 01 2012
David Montgomery

This discussion convinced me that making your meaurements based on your leader measurables (IE, inchs and feet) is no less rediculous that any other measurement system.

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