"Bill Sheppard" wrote in message
...
From Mark E.:

Galaxies hold themselves to a pretty
steady state of non-expansion after
presumably expanding for a while.

.And they also rotate in a more unitary or 'non-Keplerian' manner. To
explain this, a funny cosmic superglue in invoked, i.e., 'dark matter'.
This stuff is magical indeed, being invisible, transparent,
non-reflective and non-refractive, yet it holds the galaxy together in
'frisbee-like' rotation.

Why can't it just be gravity that holds galaxies and ultimately the universe
together?
Maybe gravity can cross millions or even billions of light years in some
manner of effecting itself.

Light transmits over billions of light years in every direction, and that is
a miracle in itself, considering that it goes in every direction. That is
like a drop of water being spread out evenly though an entire ocean.

So why can't gravity go in every direction over similar distances?

What 'dark matter' proponents seem to overlook is this:
A solar system has 99% of its mass concentrated in the center, in the
sun, obligating the planets to obey the orbital laws observed by Kepler.
By contrast, a galaxy has much more of its mass distributed throughout
the disc, in the spiral arms, held together by mutual gravitation. So
naturally the whole ensemble is gonna rotate in a more unitary,
non-Keplerian manner. No mystery here. The mythical/magical 'dark
matter' appears to be a solution without a problem.

Makes sense.

It seems that the universe would do
likewise.

Indeed so, if, outside our little 'bubble of visibility' (the visible
cosmos), the larger macro-universe is a rotating system. If such a
scenario were the case, spiral galaxies would be like 'little fractals'
spawned by the parent system. It'd be like Bert's "wheels within
wheels". Exactly such a scenario is proposed in the CBB model of the
universe- http://community.webtv.net/oldcoot/ContinuousBigBang
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