Gold Crown IV

Gold Crown IV
FastMikie's Fun House, Del Mar, California

Sunday, February 15, 2009

On the complexity of pool, and Life in general


The book I am currently reading 


gave an interesting example of the complexity of life and the impossibility of predicting future events.  It used the actions of billiard balls on a table as an example.  Here is the example given, on page 178 of the hardcover book:

"This multiplicative difficulty leading to the need for greater and greater precision in assumptions can be illustrated with the following simple exercise concerning the prediction of the movements of billiard balls on a table.  I use the example as computed by the mathematician Michael Berry.  

If you know a set of basic parameters concerning the ball at rest, can compute the resistance of the table (quite elementary), and can gauge the strength of the impact, then it is rather easy to predict what would happen at the first hit.  The second impact becomes more complicated, but possible; you need to be more careful about your knowledge of the initial states, and more precision is called for.  

The problem is that to correctly compute the ninth impact, you need to take into account the gravitational pull of someone standing next to the table (modestly, Berry's computations use a weight of less than 150 pounds).  And to compute the fifty-sixth impact, every single elementary particle of the universe needs to be present in your assumptions!  An electron at the edge of the universe, separated from us by 10 billion light-years, must figure in the calculations, since it exerts a meaningful effect on the outcome.  

Now, consider the additional burden of having to incorporate predictions about where these variables will be in the future.  Forecasting the motion of a billiard ball on a pool table requires knowledge of the dynamics of the entire universe, down to every single atom!  

We can easily predict the movements of large objects like planets (thought not too far into the future), but the smaller entities can be difficult to figure out - and there are so many more of them."

So, the next time you miss a shot, you can blame it on some electron at the edge of the universe, or more likely, that Fat Bastard sitting on the bar stool nearby.  In any case, beware of combination shots, and don't run into any balls that are not absolutely necessary.


"Fat Bastard" a villian in the movie 
"Austin Powers: The Spy Who Shagged Me"
(and my nemesis in the 2007 US Amateur Championship)

1 comment:

Anonymous said...

"you need to take into account the gravitational pull of someone standing next to the table"

I always knew "body english" worked!