Therumancer said:
Terry is right actually.
The problem is that science fiction has become a buzzword for any kind of work of fiction set in space or whatever. If it has robots and ray guns, then it's science fiction.
Science Fiction as a genere is characterized by trying to present things in a plausible light. While fantastic technologies might be invented, a lot of time is spent explaining how they might work, and what the repercussions might be, and exploring those elements within a story.
Things like "Doctor Who" and indeed most popular "sci-fi" are technically fantasy, or "space fantasy" if you need a sub-genere. Though for people today "fantasy" is generally considered to be sword and sorcery even if that isn't generally true.
I think you've hit on the semantic gap, here. I used to hear
Star Wars referred to "Space Opera," but I think that term has faded from use and doesn't really apply to Doctor Who. I remember people trying to use "Science Fantasy," but I don't think that got any traction either. We really don't have recognizable terms to distinguish between "story that draws from modern theoretical science in a believable fashion" and "pulp entertainment set in the future."
And for people saying there isn't time for a full explanation in an hour long show, maybe not, but in my experience, well written shows can still maintain suspension of disbelief with small touches that make the world seem consistent.
Firefly and
Cowboy Bebop both did this well in my opinion.
Firefly with small touches like "Vera" not being able to be fired without air around her or Serenity not being able to maintain oxygen without a running engine, not to mention not having sound in space, and
Cowboy Bebop with details like spacesuits having magnetic boots to walk on ship hulls in zero-g and all large ships having rotating rings to create artificial gravity. Heck, in one episode Spike saves himself from drifting away in zero gravity by using Newtonian physics, which is certainly more satisfying than suddenly having him have rocket boots or a magical screwdriver or something.