In science fiction movies, like Star Wars and Star Trek, etc , nobody is shown as weightless as a normal condition on a space ship. Isn’t this inaccurate? Wouldn’t weightlessness be the default condition on a spacecraft? There’s no “up” or “down” out there in space? Is there such a thing as artificial gravity on space craft? Or is this something that is fanwanked or fake-scienced away just to make the situation easier for the filmmakers to deal with?
Of course there’s artificial gravity. It’s the 23rd century, after all.
And let’s not get started on the Heisenburg compensators on the transporters. 
Artificial gravity was perfected several decades before FTL travel, so sure, it’s reasonable.
You can easily have the illusion of gravity even using 20th century technology. Artificial gravity is just another step.
Generally, yes, it’s just far easier (and cheaper) to film it that way. As a result, in most SF movies and shows, zero-G only comes into play when there’s a need for it in the plot.
Also, you may get some argument about Star Wars really being “science fiction”. I’ve seen it referred to as “space opera”, but, in many ways, it’s a swords-and-sorcery fantasy series that just happens to take place in space.
I think this is the more common reason. However, considering the advanced science in some of these films - lightsabers in Star Wars, teleporters and holodecks in Star Trek - I don’t think that artificial gravity is so farfetched in relative complexity.
Zero-g is really, really hard to do well, even with modern computerized special effects. The only film that did it well was Apoll 13, and that wasn’t simulated: They actually got cooperation from NASA to film on the Vomit Comet (which, needless to say, isn’t usually an option). So you pretty much always have to introduce something to avoid needing zero-G, whether it be technobabble artificial gravity (like Star Trek), realistically-plausible artificial gravity (like Babylon 5), or, if nothing else, at least something like velcro shoes.
1.) If you’re going to accept the camel of faster-than-light travel, it’s not much more effort to swallow the gnat of artificial gravity
2.) In the poorly-funded world of 20th and early 21st century cinema and television, convincing weightlessness was generally prohibitively expensive (read Heinlein’s essay on “Making Destination Moon”, or Jerome Agel’s book on the making of 2001). Plus, your typical production executive would just say “People don’t know about it, and don’t care. Let’s spend the money on something else.”
3.) What I really want to see is convincing low gravity. No movie set on Mars or the Moon even attempts to show this, except for a few scenes outside in space suits on the Moon, perhaps. But on the indoor sets everybody moves in gravity as high as, well, California’s.
2001: A Space Odyssey had both believable artificial gravity (created by the space craft rotating) and believable people floating within and outside space craft, so it can be done, even with 40-year-old movie-making technology (2001 was filmed in 1968).
Actually, it is a combination of Kurosawa’s The Hidden Fortress, The Dam Busters, and The Guns of Navarone.
Although took more than five years for Kubrick to make the film including tearing down and completely rebuilding the sets when he wasn’t satisfied.
Stranger
Well, he was a bit of a perfectionist …
If you are going to let the concept of inertia take a holiday during science fiction films/television, the concept of artificial gravity isn’t that hard to accept. Especially since you can solve the artificial gravity issue simply by making the ship cylindrical and putting spin on it.
Inertia, now, that’s a bit harder to deal with…
There are some other reasons why artificial gravity of some sort is likely to be required. First, it is far from clear that humans can stay healthy on five year missions in a zero-g environment. Second, the red shirts will be in even more trouble trying to adjust from a zero-g Enterprise to a more or less 1-g planet every few weeks. Third, if you buy tractor beams, you buy artificial gravity. The only way I can think of implementing a tractor beam is through some controlled stream of gravitons. Have that, you just put a whole bunch of diffuse tractor beams in the floors, and you have artificial gravity also.
I keep hearing that, but then how do you explain Eyes Wide Shut?
One of the Star Trek shows paid their respects to 0-g in one scene - on (Deep Space 9? I think) two of the cast ended up hitching a ride on some freight ship, and the scene showed them, moderately pissed off, floating in some side bay.
Artificial gravity is WAY more plausible than FTL travel. It’s strange to accept one and reject the other.
As far as we know, FTL travel is flatly impossible. The same is not true for artificial gravity. We don’t know how to do it, but we don’t know of any laws that say it’s impossible, either.
Currently.
There are hypotheticals like traversable wormholes.
Given that zero-G has some tough effects on the human body (not to mention simply making a lot of little tasks much harder to do), it shouldn’t be surprising that some sort of artifical gravity would be high on the priority list for people planning any sort of extended space travel.
Well, there’s no indication that true artificial gravity is possible, but we know of at least a few ways to fake it. You could keep your ship constantly accelerating (great if you can pull it off, for a variety of reasons, but probably impractical), you can spin your ship, or you could use extremely strong magnetic fields to diamagnetically repel the water in human bodies away from the ceiling (this last one could also be used to make an effective “intertial damper”).
You sure that wasn’t B5? There was a bit with Dr. Franklin and Marcus in just that situation. I don’t remember anything like that from DS9, though if anybody else does, I can check my DVDs when I get home. Same goes for B5.