re: Don't work too hard at this.
And, as you know, not all scifi is hard scifi.
Ronald Moore, one of the driving forces behind Galactica, has held from the beginning that effect is more important than cause. Don't misinterpret that as meaning he isn't concerned with character or motivation. We're talking about something different here. It's the difference between thinking your way through a story vs feeling your way. Neither is inherently wrong, and the latter doesn't constitute failure any more than a scientifically accurate peice constitutes success.
I'm reminded of Harlan Ellison's old wish that the term "science fiction" be replaced with "speculative fiction." (Insert the inevitable lament that Ellison was scientifically illiterate here...)