I'm a logic geek, and I make time to care about that stuff. If I wrote a story with a star system populated like that, my betas would slap me silly unless I had a damned good reason for it.

I still don't see how that's different than tacitly assuming there's a medium in space through which sound can travel; the only reason they wouldn't slap you for that is that it's accepted. It's not any less wrong.

I think the one saving grace is that there have been in-series references to terraforming. Perhaps the system had a big asteroid belt or Oort cloud in the temperate range around the primary, and extensive terraforming has resulted in so many habitable worlds? Ariel and Persephone are the only planets I remember being densely populated (and therefore probably habitable for hundreds of years).

Weren't a lot of the planets actually moons of bigger planets (like gas giants or such)?

Yo, ita! Was your moon terraformed?

Way I see it, it's no good being bothered by this and not caring that space has sound in just about every other SF 'verse.

That was one of the things FIREFLY did right, though. It stood out for me, what with the effective way Joss used it in "Objects in Space" and "Out of Gas".

Betsy's right: Joss doesn't have sound in space. Which is one of the things that I love, but then it makes me crazy when he gets other, basic, scientific things wrong.

Like forgetting space has 3 dimensions: they couldn't just go around the Reavers?

Because decades of sci-fi have trained people think of space as being something like the Earth's surface in many ways. You cross it like you cross a landmass or an ocean. There are precise paths and your destination won't move. Everything's on more or less a plane with no real Z axis to speak of. It's not remotely true, but that's how we've learned to visualize it. It's part of overall sci-fi canon. Thus, trying to represent maps of outer space in true three-dimensional style can be difficult to grasp to some people, so Joss has gone with a more traditional approach--2D approximations. Everyone understands those.

If they'd chosen to break with tradition and go full-on 3D, they could have just said the Reavers claimed the entire surrounding sector (or whatever) of space.

As Matt said above, the reference to terraforming makes the multi-planet solar system less unlikely. They had scouted the local univerise via robot ships for scientific reasons over the millenium before earth was destroyed. When it became obvious that earth was at an end, they picked the solar system most like what they needed and engineered it the rest of the way - not always getting things exactly like they wanted. Not even a huge wank. You can justify 90% of that logic chain from series or film cannon. The parts you can't are not really a hell of stretch, given the capabilities implied and the time passed.

I never knew before how hard it is to be spoiled. Yesterday when everyone was nattering about which Serenity crew-member would be which Star Wars character and ita said something about "Unca Wash" -- I ALMOST said that it could never be and then I remembered.

Poor Wash. And poor us -- I already miss him.

It is hard. Sometimes when I know a secret I feel like I'm going to say it involuntarily. Like if someone says to me "Hey, it's a nice day outside", I have a knee jerk reaction to say "Wash dies!".