"Paul Hollister" wrote in message
oups.com...
Is the whole of the galaxy a centrifuge or a centripetal drain?

Neither. The centrifugal and centripetal effects must
be roughly balanced for the stars to continue to orbit
around the centre. If either predominated, the galaxy
would have collapsed or dispersed by now.

If the
supermassive black hole in the nuclear center of each galaxy has been
formed by "gobbling up" millions and billions of stars as current
theories suggest, then the galaxy is a centripetal drain, wherein the
black hole is swallowing the mass of the galaxy star by star.

Look up the star "S2" which passes within 17 light hours
of the central black hole. It hasn't been swallowed yet.

However,
the spiral arm structure of spiral galaxies appear as if they were
formed by centrifugal force! What do you think?

In reality the motion of individual stars is quite chaotic
as they are influenced by all their neighbours. The arms
are more stable because they represent something like a
wave of new stars that moves through the disk material.

George