Some people like hard science fiction that is hard science fiction. The science is the star, the characters are the supporting roles.
They never had big budgets. The real reason was that Roddenberry distanced himself from the show, after NBC moved it to the death slot of 10 PM Friday, and the new producer didn’t get it. Source is one of the extras on the TOS remastered boxed set, third season. They all knew they were doing to get cancelled, so no one gave a shit.
I’m a bit surprised that no one has mentioned the recent sci-fi phenomenon of a dismembered arm writing a message that reveals the location of a missing gyroscope. I doubt that could happen in real life. 
Um. You sure you aren’t on that other kind of dope?
I had heard the writer of Spock’s Brain, Gene L. Coon, who wrote it under the pseudonym of Lee Cronin, deliberately wrote such a campy script to prove the new producer wouldn’t recognize bad science fiction if it bit him on the ass. I can’t find a cite anymore, but it sounds plausible, since Coon was such a good writer and producer and created much of the canon for the original series.
Heh. The arm had a guest appearance in The Cloverfield Pardox. I’m not sure I can recommend watching the movie, but you can read about it in this thread.
I really, really want a replicator though. Any hope of that ever happening?
There is room for all of it. I don’t have a problem with impossibilities in science fiction, so long as some attempt is made to justify it, and so long as the rules are known and the universe sticks to those rules.
What I can’t stand is technobabble used to enable sloppy writing. Our heros get into a jam, and it looks like there is no way out. But suddenly, Giordi realizes that he can just reverse the polarity on the subspace confabulator in his wristwatch, and it will open up a space-time rift that swallows their enemies up in quantum vortex! Yay! And the writers get to knock off early and go for beers.
There is real hard science fiction out there. Heinlein and his wife would spend days doing laborious manual orbital calculations just so he could get the numbers right reagarding how long part of a spaceflight would be. While some of his stories had FTL, others had generation ships that rotated to provide gravity. Other writers like Robert Forward and Gregory Benford are actual physicists and sometimes would write science fiction as hard as it can possibly be.
I’d distinguish stuff we are sure is impossible (‘shock waves’ in a vacuum) with stuff we believe is impossible (or impractical if at all technically possible, like faster-than-light or any other end-around the enormous time elapse, as experienced at the point of departure, of interstellar travel).
I’m sure there’s a wide range of levels of understanding of physics of people posting here. I don’t expect mine ranks all that high beyond Newtonian, just a general idea. Still, even the most learned people thought a lot of stuff was impossible till it wasn’t.
That said, it doesn’t really stand in the way of good fiction that it presents impossible things. As another post noted, good non-science fiction is often full of extremely unlikely things (in the way of coincidences, who could be romantically attracted to whom, super brilliant renaissance people as protagonists in detective stories, etc). Although one might wish for more science fiction that accepted our current understanding of physics as the final fact, then tackled the question of why societies would send off distant interstellar space expeditions whose results they couldn’t know for centuries or millennia. Some have, but it’s no surprise the vast majority of space travel sci-fi writers have instead found devices to make the time dynamics more like sea voyages on earth.
I once again point out this essay.
Not exactly. Relativity can describe what’s necessary to make time travel (or equivalently, FTL) possible. And for every scheme that anyone’s come up with, what’s necessary turns out to be, basically, some sort of matter with a negative mass. So we haven’t actually solved the question of whether time travel is possible; we’ve just shuffled it off to the question of whether negative mass is possible. Nobody’s ever found any, and so far as we know it isn’t possible, but maybe we missed something that does make it possible. If we did, how difficult/impractical is that something we missed? We don’t know, because we don’t know what that something is.
Sometimes, really, really, really, really, really, really, really, really, really, really, really, really, really, really, really, really, really, really, really, really, really, really, really, really, really, really, large amounts of negative mass.
I’ve seen at least one variation of the Alcubierre drive that uses an arbitrarily small amount of negative mass. Whovians will be amused to learn that it involves putting the ship in a region of space that’s bigger on the inside.
Chronosynclastic Fundibulum.
ONe thing I think is underdiscussed is how much that we consider science fiction can just eventually be experienced in a virtual reality indistinguishable from reality. If you want to be shrunken to six inches tall in a simulated reality, that’s no problem at all. Want to switch bodies with someone? You can do that too. Time travel? Why not?
Now of course there are many things in science fiction involving things we would want to do for real, like find out if there are other civilizations out there or learn more about the origins of the universe, or if there is a multiverse, or if we’re in a simulation right now. But for those who want to do wicked cool stuff, that should be possible, maybe in our lifetimes.
Yeah, to create virtual reality indistinguishable from reality, you need to not only control vision and hearing with displays and speakers, you also have to simulate taste, olfaction, touch, heat and cold reception, pain reception, position of the body and its parts in 3D space, sense of acceleration, and probably more that I’m forgetting. Good luck with that.
Or you can just go directly into the mind an give people customized dreams.
There’s also of course a serious cool factor with simulation technology not indistinguishable from reality. People love scifi movies and video games where they get to see laser guns and time travel and those technologies keep on getting more immersive. Soon we’ll have really good virtual reality where at least sight and sound are nearly perfect.
That’s interesting but I’m not sure how relevant it is to saying we couldn’t eventually find (or civilizations with say a million years head start could not have already found) a way around the extremely long time (at the point of departure) required for interstellar travel. It wouldn’t necessarily have to involve a difference in overall understanding comparable to flat v round earth, and OTOH just because the more subtle difference between seeing the earth as spherical v spheroid has little practical effect doesn’t mean all subtle differences in understanding of physics would have as little practical effect.
Also I was thinking more broadly than necessarily a gadget (like ‘warp drive’) which would reduce the timescale of interstellar travel to that of terrestrial transoceanic voyages and everything else about the ‘ship’, society and human existence remains some fairly close variation on things as they are. Which describes most space travel sci-fi, certainly which reaches TV or movie screens at least, and the variations in society are often really a vehicle for commentary on today’s society; relatively seldom is it assumed ‘human nature’ is really entirely different. Changes in the basic nature of society and existence could result in it making sense to devote huge amounts of scarce resources (like Moon or Mars exploration now) to projects whose results can’t be known at the point of departure for perhaps centuries or more. Which is the part about distant interstellar travel that’s most hard to believe now IMO. Immortality or collective consciousness might be ways around that in the societal sense.
There’s another class of SF ‘errors’, where they use technology in a way that doesn’t make sense in real life. For example, it’s really common for SF (especially TV SF) to use ray guns that are inferior to and more expensive than modern firearms, or to use higher energy ray guns that lack simple features of firearms like sights or lights and don’t even think about things like being able to shoot around corners.. And sometimes the tech idea is just silly to the point of absurdity, like the spaceship fire control system from the lamentable B5 spinoff Legend of the Rangers.
It’s not just weapons, a lot of SF before the cell phone/smart phone era would make plots that seem silly to us now that ‘forgot’ that people were carrying a device that allows instant communication and location. And a lot of SF has truly amazing tech that has earth-shattering implications, like a lot of transporter beam, AI, and replicator/nanotech devices.