🚀 go-pugleaf

In article <JMC.92Dec29211051@SAIL.Stanford.EDU> jmc@SAIL.Stanford.EDU (John  
McCarthy) writes:
> By the way, it seems to me that if the above idea is sound, it settles
> the question of the stability of the solar system - in the negative.
> Very likely an asteroid could be tamed over a sufficiently long time
> with as small an expenditure of delta-v as might be desired.  Once
> tamed it could be used with infinitesimal external force to expel a
> planet from the system.  This tells us that the current trajectory of
> the solar system is arbitarily close to one in which a planet is
> expelled.  Of course, the probability that a planet actually would be
> expelled by this mechanism in some particular finite time is extremely
> low, because maintaining the required sequence of encounters requires
> an improbable precision in the initial conditions.  I suppose a lower
> bound on the probability could be computed and from it an expected
> upper bound on the gravitational lifetime of the solar system could be
> obtained.

Hurray!  My Douglas Adamsian speculations were not totally hougwash :-)

More seriously, In the most recent Sci Am or Sky and Telescope 
(I was reading both last night and get confused) there is piece about
work by the group at MIT with the special purspose celestial 
mechanical computer (sorry for vagueness, but mags are at home)
concerning chaotic dynamics in the solar system.  The original work
is reported in a July issue of Science, but I missed the original.

The upshot is they simulated the solar system's dynamics for some 100
million years and made several runs after slightly (1 millimeter !)
perturbing the position of each planet.  The article showed a graph
of the expeonential (hence chaotic) divergence in the position of
Pluto for the 1 mm perturbation in Venus's position.  After 100 myear
Plutos position had changed by quite some million miles.

Hey, maybe Pluto would be better than Ceres.  Kick a periodic comet
so it ricochets of Pluto.  Pluto Ricochets off Neptune, then off Jupiter
and into the inner solar system where it becomes tame!

--
Thomas Clarke
Institute for Simulation and Training, University of Central FL
12424 Research Parkway, Suite 300, Orlando, FL 32826
(407)658-5030, FAX: (407)658-5059, clarke@acme.ucf.edu