At several points in the series, you view Serenity from behind as she fires the main drive. The view of the background “warps” around the engine. The engine also only fires for short time. This is reasonable. In space you only need to accelerate at the start of the journey and then decelerate at the end. Most of the time is spent coasting.
I always assumed the yellow/orange glow at the back of the Firefly was some sort of space drive and the engines on the sides were for in atmosphere.
Well, it’s hard to see how terraforming could transform, for instance, Pluto into a planet where liquid water could exist. Larry was pointing out that there’s a limited range of distances from the star where life could survive. I don’t see how terraforming could affect that. But, hey, this is sci-fi. They could have pulled a Lensman and hooked up drives to push the planets around into orbits they liked better.
Back to the OP, I thought it was left quite vague in the series, then clarified in the movie. In fact, when the show was broadcast, they included an introductory voiceover. There were two versions, one by Mal and one by Book. One of them implied they were in separate systems and one implied it was all one system. Maybe Joss ‘n’ crew just hadn’t decided yet.
Which is why having multiple systems inside a larger system would work better.
I fear we are overthinking the issue…
Who? Us? Never. 
It actually reminds me of the original setup for Mobile Suit Gundam, with the Outer Colonies and the Sides in revolt against Terra.
Sure – if you’re not in a hurry. Just getting to Mars that way would take, what, 6 months? A year?
Well, it depends on how fast you’re going.
The Earth-Mars distance varies between about 56 million and 400 million km. Given the Firefly universe, traveling 1% of the speed of light seems reasonable. 0.01 c is 3x10[sup]6[/sup] m/s or 3x10[sup]4[/sup] km/s. So, a trip to Mars at 0.01c would take between 1.3 and 9.3 days.
Now, how you accelerate to 0.01 c in a few minutes without flattening everyone on the ship is another problem. I think Joss is trying to show some advanced, non-Newtonian propulsion system. Hence, the light being warped by the drive.
Well yes, but that distance can be HUGE.
For instance, a hot blue star can have a ‘habitable zone’ I believe larger than 10 AU, given suitably thick greenhouses on the outer planets. From this table, even Procyon, only 1.2 solar masses, could have a habitable zone from 2 to 6.4 AU. How big would the habitable zone be around, say, a B5 star, 5 times as big as the sun and giving off 700 times as much light? Or to be less extreme, how about a star like Vega, which is about 50 times as bright as our sun, and only 25 light years away?
I think some of the more hard-core science guys here are actually getting tripped up with the wrong science. I read lots about habitable zones years ago with regards to SETI. The thing is, they’re only looking for habitable zones around smallish stars like our Sun, under the assumption that the bigger, hotter stars simply couldn’t exist long enough for intelligent life to form. Also, a lot of the calculations you see for habitable zones are ‘continuously habitable’, meaning that they stay within the freezing point of water throughout the life of the star. That’s a much smaller zone. For these reasons, the calculations I’ve been able to find don’t even bother to figure out the habitable zones of extremely hot stars, because they only live maybe a billion years or so - not long enough to evolve complex life.
But in this case, that doesn’t matter, because we aren’t looking for evolved life - we’re looking for warm rocks to Terraform. And when you’re terraforming, do you really care that your star may only have a few hundred million years of life left in it?
So let’s assume a hot blue sun, with a habitable zone that goes all the way out to where Saturn would be for us. Now, imagine the terrestrial planets are maybe .25 AU apart, and the habitable zone is 10AU. That’s 40 planets in the habitable zone. Now imagine outside of that are maybe half a dozen gas giants, each with ten or twenty moons. Terraforming has allowed us to put thick greenhouses on them, so they’re on the cool side but livable. Maybe they even get some heat from theri gas giant.
(Also note that the evil corporation in the Firefly 'Verse is called “Blue Sun”).
Frankly, I find this kind of extra-terrestrial worldscape MUCH more plausible than a vast, galaxy spanning civilization and hyperdrives and whatnot, where people are flung out into thousands of light-years of space with millions of planets, yet keep running into each other and fighting over the same real estate. Not likely.
I love your Hot Blue Sun theory. If only it were so…
however, the evidence of our eyes is that the spectral range of the 'verse sun is identical to ours. I guess filming the whole thing in a colour filter would have been a bit much (but vide the series Charlie Jade if you get the chance for a look at how it could be done)
Is it possible to have a sun that gives off the same colour light as ours, but is a lot hotter? Would a bright white sun look the same as Sol when planetside? Help me out, it’s been 12 years since I took Astro201, and even then I don’t think we ever discussed this.
You can get significantly hotter/brighter while still staying within roughly the same color range. Furthermore, it’s not always that easy to tell color differences in lights of different intensity.
Anyway, we’re not talking about major differences. To most people, the sun’s light looks ‘white’, although it’s on the yellow side of white. Vega would also look ‘white’, but with a blue cast instead of a yellow cast. I don’t think the difference is all that significant, especially given the difference between camera films, filters, etc. And besides, didn’t Miranda look awfully bright and didn’t the light have kind of a white/blue cast to it?
The Serenityverse definitely has FTL communications (‘the wave’). Personally, I got the feeling that it was set in a system of multiple stars.
So the answer, if I understand correctly, is “Yes - a hotter star won’t be noticeably different on the ground, even if it is what we’d call a blue star”. Thanks, Sam.
The quality of light would be somewhat different, but I think the bigger factor would be atmosphere of the planet - how many particulates there are, etc. But all else being equal, instead of getting a yellow/white light like we get from the sun, it would be a blue/white light. But the eyes do adapt. Consider how much more yellow interior incandescent light is. It looks pretty normal to us, but if you take a picture with a camera that doesn’t have a white balance control or circuit, the picture will come out looking a lot more yellow that you remembered.
If it seems improbable that such a star system exists with many habitable planets and moons (even if some or most needed a bit of terraforming), recall that the ancestors of the people in the system were part of a large-scale migration from Earth. It would take years or decades to prepare such an undertaking, during which time long-range surveys of extrasolar planets could be underway (presumably using technology several orders of magnitude more sensitive that what we have now). By the time the colonists left Earth, they had picked out the single most promising star system. Even if the odds are one in a billion that such a system exists, they have 100 billion stars to choose from in the Milky Way alone.
How they made the voyage, be it with FTL, sleeper ships or generational ships, is unclear.
Unclear, or at least I don’t remember if the movie mentioned it.
The movie never mentioned it.
Also: not all planets/moons have the same environments, even after terraforming. “The Message” makes it clear that at least one moon is extremely cold.
Joss has flat-out stated that the trip took years…no FTL.
Just what did you get from ‘the wave’ to decide that it was FTL? Myself, now that I’ve seen the movie, I’ve been assuming it’s just a system of radio, microwave, possible IR laser transmissions.
(Of course, they never show a noticeable transmission lag when getting a wave from another planet, when it would probably have been a noticeable number of seconds or more in some cases - but I think this is allowable stretching in the genre. 
)
Nope.
For those who still think it didn’t take place in one system, here’s the opening monologue:
I don’t think that leaves any doubt.