solar system's galactic motion question

hi
i've seen many sources speak of the synodic or "porpoise-like" motion
of the solar system as it travels through the milky way. it seems to
be a well known fact these days, yet i can not seem to find any
reference to WHY this motion occurs as opposed to a motion along a
flat orbital plane. does anyone know or have helpful info on this
question?
thanks for your help,
reuben

"Reuben Temple" wrote in message
om...
hi
i've seen many sources speak of the synodic or "porpoise-like" motion
of the solar system as it travels through the milky way. it seems to
be a well known fact these days, yet i can not seem to find any
reference to WHY this motion occurs as opposed to a motion along a
flat orbital plane. does anyone know or have helpful info on this
question?
thanks for your help,
reuben

The gravity field of the galaxy is not a simple
spherical potential like that of a point mass.
This means that Kepler's laws won't strictly
apply, and orbits other than simple ellipses will
occur. In fact, the orbit of any given star can
be quite complex and even chaotic. It's an
interesting field of study.

Here's a link to get started:

http://burro.astr.cwru.edu/JavaLab/SOSweb/backgrnd.html

If you want more in-depth information, I can suggest
the book "Galactic Dynamics" by Binny and Tremaine.
It's the gold standard.