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> Science fiction almost universally assumes the speed of light is not a hard limit. Not at all, you need to look at other sub-genres. The social, economic an

> Science fiction almost universally assumes the speed of light is not a hard limit. Not at all, you need to look at other sub-genres. The social, economic and military structures that form around slower than light travel are a mainstay of hard science fiction. "A Deepness in the Sky" is a great example. So is the first half of "Neptune's Brood" or the second half of "Accelerando". Any story that uses a generation ship as the setting, like "Hull Zero Three", also assumes sub-light travel. Or what would happen if present-day society discovered an alien race next door, like in "The Sparrow". Or maybe we need to make ourselves slightly less human to survive sub-light space travel. "Blindsight" and "Echopraxia" explore the philospohical ramifications of that. Even "Ender's Game" doesn't have FTL travel. Now space opera almost universally assumes that FTL is possible. Though there are exceptions, Ian Banks "The Algebraist" is my favorite sub-light space opera. edit: Some hard sci-fi will still use wormholes, either as a normal thing or a macguffin. FTL communication is also common. Though FTL comms are getting less common in modern hard sci fi. Us readers like this and it makes for convenient plot devices as comm lag leads to misunderstandings. TV and movies are almost always space opera, with "The Expanse" being the only sub-light TV production that comes to mind, and "2001" for film. But I don't know as much about film as books.

badloginagain 9y ago
Just wanted to mention The Expanse, which definitely has hard limits on going over (or even reaching) the speed of light, and touches on many of the tropes you mentioned. It's also probably one of the best examples I've seen of a truly alien encounter- no bipedal humaniods with spoken language. The book series is excellent, and it has two seasons released from SyFy, which does a pretty good job capturing the feeling the books.
- ianai 9y ago
  How do they zip around the solar system so quickly? It seems like at various points they go from earth to where ever almost instantaneously (in the show, that is). Not a troll - I'm genuinely wondering what I missed from the episodes.
  - Casseres 9y ago
    In the books, the sense of time it takes is conveyed. I don't think they're treating it as instantaneous in the show; just that they're keeping the story moving along because it makes for better TV. If you like the show and you like reading novels, I highly recommend the book series.
  - sitharus 9y ago
    Same as in most tv shows, they skip the boring bits. Travel times are mentioned occasionally and they are consistent with ships that can do a brachistochrone orbit at a constant 0.3 or 1f acceleration. This would be a few days between most locations mentioned iirc.
  - amorphid 9y ago
    Ships get around the solar system using a propulsion system called an Epstein Drive. I just watched the following video yesterday. The narrator talks about travel times to different planets using a flip and burn technique (accelerating at a constant rate to half way point flipping direction, and decelerating at the same rate to the destination). https://youtu.be/hz7jETrejCQ https://youtu.be/hz7jETrejCQ P.S. I love the Expanse :) I'm glad it was renewed for Season 3. Best sci-fi I've seen on TV since Battlestar Galactica.
  - badloginagain 9y ago
    Basically the Epstein drive allows for basically unlimited thrust, which is what gives most ships on the show gravity. Unlimited thrust == unlimited acceleration. When they reach the halfway point, they 'flip and burn'; turning around and start accelerating away from the destination to slow their relative velocity.
- keenerd 9y ago
  Coincidentally I'm working through the book series right now. It is mostly good, though it would be nice if the main characters weren't quite as consistently lucky. The author's handling of energy is really annoying. I can overlook the structural impossibility of spinning up an asteroid for example, but I can't overlook the fact that they can command that sort of energy. It is made even more frustrating because they understand the offensive capabilities of kinetic weapons and rocket exhaust. For example, the mirror array on Ganymede was stupid. The greenhouses use electric lighting for half of the time anyway, when behind Jupiter. Why build this giant orbital mirror array when you could install a second fusion reactor instead and leave the lights on all the time? And then it could all be underground too. Magnetospheres make some locations very desirable. Why not lay down some super conducting cables, hook up a fusion reactor to it and make your own magnetosphere? This would have been a great plot device too, since any rich civilized place would do it, but it also makes detection of the habitat trivial. Poorer places would keep their's off and take the risk of cancer, turning it on only for protection from solar flare bursts. Seedy places would never install one at all.
  - greglindahl 9y ago
    If you're interested in the science behind spinning asteroids, check out https://en.wikipedia.org/wiki/Yarkovsky%E2%80%93O%27Keefe%E2%80%93Radzievskii%E2%80%93Paddack_effect https://en.wikipedia.org/wiki/Yarkovsky%E2%80%93O%27Keefe%E2...
    - keenerd 9y ago
      That has nothing to do with what I'm talking about. In The Expanse, they hollow out and spin up asteroids to use as a space station with centripetal artificial garavity. A typical rubble-pile asteroid would fly apart well before that. Even solid rock couldn't take the forces since they are all tensile.
      - greglindahl 9y ago
        Sorry, I thought you (or the other people reading this thread) might be interested in how asteroids behave in the real world. I wasn't saying that's what was happening in the show.
- svachalek 9y ago
  spoilers It sounds like you may not have read all the books yet.
  - keenerd 9y ago
    Everyone says that after book 3 or 4 they go downhill anyway. I like to believe there was only one Matrix movie ever made and only one Dune novel. I will probably prefer to believe that there were actually 9-N books in The Expanse series, where N has yet to be determined.
    - ethbro 9y ago
      I'm rereading the Dune series right now and on Children of Dune. Actually REALLY enjoying the 2+ books more than the first. What would one do if one had become a human god but didn't like the future he saw? Like the post-Ender's books (before Card sold out), I find mulling over the consequences of upsetting an applecart far more interesting than the upsetting. The first books in both series feel a bit too "Mission Accomplished!", pat-on-the-back in hindsight.
      - keenerd 9y ago
        For me it is all about the world building, the practicalness of the universe presented. Dune had a decade of planning go into it before the first book was written. The rest did not have that amount of background effort and it shows. After the first book it all feels like he's making it up as he goes along, instead of drawing on an encyclopedia. Children of Dune had the most egregious problem with this. Trying here to not spoil the plot for you, but at towards the end (page 329 of 408 in my edition) Leto discovers something profound. The backstory to introduce this was first mentioned on the previous page. It didn't use some bit of trivial from the first two books, and he couldn't be bothered to write it 300 pages earlier either. (Feel free to email me when you think you've reached that part.) The later novels are slightly better, then he's writing these new discoveries into the previous chapter. Re-reading Dune has always been pleasurable for me. You can feel it is just the tip of an iceberg and tease out the history by reading between the lines. The other books lurch from one deus ex machina to another. Ender's Game is also largely about consequences too. Humanity wins the fight and destroys the big bad, but this doesn't happen at the end of the book. There is still a third of the story left to mull over the consequences. edit: Slight spoilers, but nearly all of the later Dune books essentially allow anyone to come back from the dead. He never once explores the ramifications of this. What happens if you try to bring back multiple copies of someone at once? Does every cell in our body really carry the full weight of our entire past experience? What about identical twins? What if you blended the nucleus of one person with the mitochondria of a second and the cellular plasma of a third? Or does the procedure somehow tap into the soul? Is god annoyed that the natural cycle is broken? Does the process damage the soul? Never once delves into any of this, instead it is used only as a cop-out to avoid creating new characters.

badloginagain 9y ago

Just wanted to mention The Expanse, which definitely has hard limits on going over (or even reaching) the speed of light, and touches on many of the tropes you mentioned. It's also probably one of the best examples I've seen of a truly alien encounter- no bipedal humaniods with spoken language. The book series is excellent, and it has two seasons released from SyFy, which does a pretty good job capturing the feeling the books.

ianai 9y ago
How do they zip around the solar system so quickly? It seems like at various points they go from earth to where ever almost instantaneously (in the show, that is). Not a troll - I'm genuinely wondering what I missed from the episodes.
- Casseres 9y ago
  In the books, the sense of time it takes is conveyed. I don't think they're treating it as instantaneous in the show; just that they're keeping the story moving along because it makes for better TV. If you like the show and you like reading novels, I highly recommend the book series.
- sitharus 9y ago
  Same as in most tv shows, they skip the boring bits. Travel times are mentioned occasionally and they are consistent with ships that can do a brachistochrone orbit at a constant 0.3 or 1f acceleration. This would be a few days between most locations mentioned iirc.
- amorphid 9y ago
  Ships get around the solar system using a propulsion system called an Epstein Drive. I just watched the following video yesterday. The narrator talks about travel times to different planets using a flip and burn technique (accelerating at a constant rate to half way point flipping direction, and decelerating at the same rate to the destination). https://youtu.be/hz7jETrejCQ https://youtu.be/hz7jETrejCQ P.S. I love the Expanse :) I'm glad it was renewed for Season 3. Best sci-fi I've seen on TV since Battlestar Galactica.
- badloginagain 9y ago
  Basically the Epstein drive allows for basically unlimited thrust, which is what gives most ships on the show gravity. Unlimited thrust == unlimited acceleration. When they reach the halfway point, they 'flip and burn'; turning around and start accelerating away from the destination to slow their relative velocity.
keenerd 9y ago
Coincidentally I'm working through the book series right now. It is mostly good, though it would be nice if the main characters weren't quite as consistently lucky. The author's handling of energy is really annoying. I can overlook the structural impossibility of spinning up an asteroid for example, but I can't overlook the fact that they can command that sort of energy. It is made even more frustrating because they understand the offensive capabilities of kinetic weapons and rocket exhaust. For example, the mirror array on Ganymede was stupid. The greenhouses use electric lighting for half of the time anyway, when behind Jupiter. Why build this giant orbital mirror array when you could install a second fusion reactor instead and leave the lights on all the time? And then it could all be underground too. Magnetospheres make some locations very desirable. Why not lay down some super conducting cables, hook up a fusion reactor to it and make your own magnetosphere? This would have been a great plot device too, since any rich civilized place would do it, but it also makes detection of the habitat trivial. Poorer places would keep their's off and take the risk of cancer, turning it on only for protection from solar flare bursts. Seedy places would never install one at all.
- greglindahl 9y ago
  If you're interested in the science behind spinning asteroids, check out https://en.wikipedia.org/wiki/Yarkovsky%E2%80%93O%27Keefe%E2%80%93Radzievskii%E2%80%93Paddack_effect https://en.wikipedia.org/wiki/Yarkovsky%E2%80%93O%27Keefe%E2...
  - keenerd 9y ago
    That has nothing to do with what I'm talking about. In The Expanse, they hollow out and spin up asteroids to use as a space station with centripetal artificial garavity. A typical rubble-pile asteroid would fly apart well before that. Even solid rock couldn't take the forces since they are all tensile.
    - greglindahl 9y ago
      Sorry, I thought you (or the other people reading this thread) might be interested in how asteroids behave in the real world. I wasn't saying that's what was happening in the show.
svachalek 9y ago
spoilers It sounds like you may not have read all the books yet.
- keenerd 9y ago
  Everyone says that after book 3 or 4 they go downhill anyway. I like to believe there was only one Matrix movie ever made and only one Dune novel. I will probably prefer to believe that there were actually 9-N books in The Expanse series, where N has yet to be determined.
  - ethbro 9y ago
    I'm rereading the Dune series right now and on Children of Dune. Actually REALLY enjoying the 2+ books more than the first. What would one do if one had become a human god but didn't like the future he saw? Like the post-Ender's books (before Card sold out), I find mulling over the consequences of upsetting an applecart far more interesting than the upsetting. The first books in both series feel a bit too "Mission Accomplished!", pat-on-the-back in hindsight.
    - keenerd 9y ago
      For me it is all about the world building, the practicalness of the universe presented. Dune had a decade of planning go into it before the first book was written. The rest did not have that amount of background effort and it shows. After the first book it all feels like he's making it up as he goes along, instead of drawing on an encyclopedia. Children of Dune had the most egregious problem with this. Trying here to not spoil the plot for you, but at towards the end (page 329 of 408 in my edition) Leto discovers something profound. The backstory to introduce this was first mentioned on the previous page. It didn't use some bit of trivial from the first two books, and he couldn't be bothered to write it 300 pages earlier either. (Feel free to email me when you think you've reached that part.) The later novels are slightly better, then he's writing these new discoveries into the previous chapter. Re-reading Dune has always been pleasurable for me. You can feel it is just the tip of an iceberg and tease out the history by reading between the lines. The other books lurch from one deus ex machina to another. Ender's Game is also largely about consequences too. Humanity wins the fight and destroys the big bad, but this doesn't happen at the end of the book. There is still a third of the story left to mull over the consequences. edit: Slight spoilers, but nearly all of the later Dune books essentially allow anyone to come back from the dead. He never once explores the ramifications of this. What happens if you try to bring back multiple copies of someone at once? Does every cell in our body really carry the full weight of our entire past experience? What about identical twins? What if you blended the nucleus of one person with the mitochondria of a second and the cellular plasma of a third? Or does the procedure somehow tap into the soul? Is god annoyed that the natural cycle is broken? Does the process damage the soul? Never once delves into any of this, instead it is used only as a cop-out to avoid creating new characters.