Re: (ReacTor) Defining Our Terms: What Do We Mean by "Hard SF"?

Well, that is different in the most important point.
What the ESA discovered was that the Sagittarius galaxy passing through
the Milky Way galaxy did was accelerate _star formation_. What Smith was
saying was that the passage of a nebula through our galaxy caused stars
to form _planetary systems_; at the time, it was believed that planetary
systems were rare, and resulted from close encounters between stars.
We know better now; we know that the formation of a planetary disk is a
natural result of a star condensing from gaseous matter and shedding
angular momentum.
John Savard