VERSION|0.5.1|NAME|David Harper|DATE|1365070983|CONTENT|HarryR:
[blockquote]Wouldn&#039;t the counter rotating bits keep bumping into each other slowing each other down?[/blockquote]
Galaxies are mostly empty space, despite what the photograph might lead you to think.

The dynamics of the stars at the interface of the two counter-rotating regions might be very interesting, but there are unlikely to be any actual collisions between stars, so there&#039;s no &quot;friction&quot; between the regions.

The stars in the outer region will feel the combined gravity of the stars in the inner region, but since (at least in a non-relativistic regime) the gravitational field of a star depends only on its mass and position, and NOT its velocity, the combined field of all the inner stars would be the same if they were orbiting clockwise as if they were orbiting anti-clockwise.

I hope this makes sense.|IP-ADDRESS|172.20.128.250|MODERATIONFLAG|