🚀 go-pugleaf

In article <1992Oct28.181745.11840@afit.af.mil> morlan@afit.af.mil (Bruce W. Morlan) writes:

   rsb@mcc.com (Richard S. Brice) writes:

   >> 
   >> >There is a greater change of dying from a train wreck or a car accident than
   >> >getting plowed by the comet. 
   >> 
   >At the macro level, i.e. the interaction of planets, stars and comets, the
   >universe seems to behave in almost clocklike manner; chance and probability
   >have only a small role.     ^^^^^

   >Would anyone care to comment on how probability plays a role in the
   >future interactions of earth and comet P/S-T and how much of the
   >script is already written into the clock?

   Sure.  The script is nearly totally written.  The Heisenberg uncertainty
   associated with the objects in question (Earth, comet, Sun, other
   planets, etc.) is practically 0 over the time frame in question.  On the
   other hand, the _uncertainty_ in the measurements leave much room for
   surprises.  I cannot comment on the measurement errors.

Well, there is a bit more to it, for example for comet interactions
outgassing can be critical, particularly if the trajectory
has a future close encounter predicted with outgassing neglected.
A very small delta v at perihelion for very high eccentricity orbits
can produce very large phase errors a hundred orbits later.
With our current knowledge outgassing is unpredictable, I suspect
it is a critical phenomenon and is intrinsically unpredictable,
eg the cracking of crust due to superheated pockets of volatiles
may literally depend on the radioactive decay of C-14 
better, the exact time cracking may in principle be triggered
by the decay of a single atom, for small enough pockets of gas ;-)

So, wenting of gas and resulting delta v may be quantum mechanically
uncertain at some level significant macroscopically...

*  Steinn Sigurdsson   			Lick Observatory      	*
*  steinly@lick.ucsc.edu		"standard disclaimer"  	*
*  The laws of gravity are very,very strict			*
*  And you're just bending them for your own benefit - B.B. 1988*