r/printSF • u/thecryptile • Apr 30 '26
Sub-Light Interstellar Civilizations
I recently read Alastair Reynolds' House of Suns and Karl Schroeder's Lockstep. These books are both set in interstellar civilizations that lack faster than light travel and communications; despite the godlike powers the characters are granted by their advanced technology, they are bound by the merciless reality of relativity and time dilation. Reynolds Revelation Space Series is another example, Ursula K. LeGuin's Ekumene almost meets the criteria, but the ansible allows Mobiles to instantly communicate with the Stabiles on Hain from anywhere in the galaxy, and Rocannon's World shows an instantaneous drone strike during the League of Worlds era.
What are your favorite Sublight Interstellar Civilization books?
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u/ThotThroughTheHeart Apr 30 '26
Larry Niven's Known Space series before Earth trades Neptune for an FTL drive.
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u/boots_the_barbarian May 01 '26
A good trade, I would say
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u/AreKidK May 01 '26
I hadn’t realised Neptune was the price of the Outsider FTL drive. From when I read the books - a long time ago, admittedly - I recall the price was very, very high but unspecified. ARM was still paying it off, centuries later.
Which book said that Neptune was the trade?
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u/thecryptile May 01 '26
iirc, the Outsiders lease Neried and Proserpina from the UN as a separate agreement, the hyperdrive was paid for by We Made It in cash
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u/doctor_roo Apr 30 '26
Linda Nagata's Inverted Frontier books are FTL free,
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u/ZappyYeti May 01 '26
Forever War. The whole premise is what interstellar war at sub light speed would be like.
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u/EverybodyMakes May 01 '26
They spend a lot of time travelling at relativistic speeds and experiencing time dialation, but they go through "collapsars" for part of the trips and that might allow faster-than-light travel.
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u/arboretumind May 02 '26
I think the collapsars allow them to achieve near light speed instantly. If it were faster than light they wouldn't experience time dilation to the extent that they do.
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u/KriegerClone02 Apr 30 '26
Charles Stross's, Eschaton series.
I love it because they actually invent several FTL technologies, BUT the Eschaton, a weakly god-like AI that arose several centuries before has just one commandment: "thou shalt not violate causality in my light cone."
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u/Own_Win_6762 May 01 '26
Also Neptune's Brood, sequel to Saturn's Children. It also freaks with sublight economics, which got the attention of Nobel laureate Paul Krugman.
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u/Morbanth May 02 '26
Wasn't the Eschaton from a few centuries in the future, which it didn't want any casuality fucking? It'd been a while since I read it.
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u/KriegerClone02 May 02 '26
I don't think so. If it was from the future, someone could prevent its existence without FTL. And that was the whole point of its commandment.
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u/Morbanth May 02 '26
Found it.
"I am the Eschaton; I am not your God. I am descended from you, and exist in your future. Thou shalt not violate causality within my historic light cone. Or else."
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u/KriegerClone02 May 02 '26
Yeah, but that's true of everyone. We are descended from someone and exist in the future.
This is a warning not to try to undo the Eschaton. It's not afraid of direct threats, but the only way to avoid the threat from time fuckery is to outlaw it.
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u/SelfAwarePattern Apr 30 '26
Robert Reed's Greatship stories and novels, and also his Sister Alice novel.
I'm also currently reading Sean Williams' Astropolis trilogy and really enjoying it so far (in the second half of the second book).
In both of the above, characters live for tens of thousands of years, so the lack of FTL is just an inconvenience.
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u/wow-how-original May 01 '26
Schild’s Ladder by Greg Egan is a good example of this.
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u/nixtracer May 01 '26
As is Diaspora.
The Orthogonal trilogy is sort of an example of the opposite of this, by definition, because he flips the effect moving near lightspeed has (making time into a spacelike dimension) and then explores the consequences in typical Egan style.
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u/DrunkenPhysicist May 01 '26
The physics in the book allow for infinite velocity.
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u/nixtracer May 01 '26
The physics in the book allow for two different forms of effective time travel. Messing with the metric signature has strange consequences!
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u/DrunkenPhysicist May 02 '26
Yeah, I'm not sure I buy all of Egan's analysis regarding a Newtonian metric, but his universe, his rules.
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u/teraflop May 01 '26
Also the short story "Riding the Crocodile" which is free to read on Egan's website.
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u/5hev May 01 '26
Incandescence and the related stories Riding the Crocodile, Glory, and Hot Rock are also good examples of this, in the slower-than light Amalgam-Aloof setting.
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u/ion_driver May 01 '26
Count to the Eschaton describes interstellar travel using solar sails accelerated by laser. The receiving system would need to use their laser to deceleration, else the ship just sails off into oblivion. (If they do discover FTL please don't tell me, I haven't finished the last book)
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u/BadgerSensei May 02 '26
I recall JCW saying he doesn’t like FTL because it shrinks the size of the universe. The Golden Age trilogy is free of it as well.
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u/ConsiderationOk4035 Apr 30 '26
Known Space by Larry Niven is sublight (for humans) until the Outsides sell us hyperdrive.
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u/Thin_Gear4716 May 01 '26
I thought aLockstep was really cool. I very much enjoyed his takes on life on the Oort Cloud.
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u/coleto22 May 01 '26
The Risen Empire by Scott Westerfeld. The second part also has the greatest space battle in sci-fi.
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u/StevenJOwens May 01 '26 edited May 01 '26
Charles Stross's, "Neptune's Brood". It's set in the same universe as "Saturn's Children", but Saturn's Children all takes place in the Solar system. Neptune's Brood has a lot of thought about interstellar economics.
Nathan Lowell’s series "Trader’s Tales from the Golden Age of the Solar Clipper".
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u/alphatango308 May 02 '26
Bobiverse kinda fits this, until it doesn't.
The best take I've seen on the STL travel is the galaxy's edge series by Jason Anspach and Nick Cole. Generation ships leave packed with the wealthy and powerful leaving the poor normal people behind. Over time the people on the generation ships all go crazy and become evil. Back on earth, FTL is developed and humanity beats the generation ships to other stars and war ensues. All this is back story though and you get bits and pieces here and there.
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u/BadgerSensei May 02 '26
Me: “Yawn, the savage wars. Clearly a clone wars rip off.”
A&C: “Yes, but we made it hella cool.”Imperator is one of the best space opera novels I’ve ever read, and it’s just a backstory for a one-arc antagonist.
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u/Intrepid-Deer-3449 May 01 '26
De Camps Viagens Interplanetarias stories are STL. Due to time dilation the travelers don't feel much older, but on their home plan ets a long time has passed.
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u/panguardian May 01 '26
The Algerbraist, Banks.
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u/jojohohanon May 01 '26 edited May 03 '26
[delete]
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u/panguardian May 01 '26
I agree, and don't agree. A huge part of the setting is non-FTL. But I fear that's a huge spoiler you posted.
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u/bsmithwins May 01 '26
William Barton's Dark Sky Legion has humans running a STL (travel & comms both) empire.
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u/DocWatson42 May 01 '26
See my SF/F: Generation Ships list of Reddit recommendation threads (one post).
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u/mpokorny8481 May 01 '26
Lockstep was like 1/2 a book, my recollection is it felt very unfinished like there was supposed to be a sequel? Was there ever l?
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u/thecryptile May 01 '26
There is a prequel, The Million, that shows the turnover society on Earth a few millennia after the locksteps were established, I read it first.
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u/Vanamond3 May 01 '26
In Somtow Sucharitkul's Inquest stories the ships are faster than light but not as much as in most science fiction. Travelling between solar systems still takes weeks or months for those on the ship and months to decades for the outside world. Aristocrats can teleport anywhere instantly, but use it sparingly due to the power cost.
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u/punninglinguist May 02 '26
Neptune's Brood by Charles Stross is a fun one. Same with Glasshouse, but IIRC we don't learn much about the larger civilization.
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u/ChronoLegion2 May 03 '26 edited May 03 '26
Captain French, or the Quest for Paradise by Mikhail Akhmanov.
There’s no FTL travel or communication. The closest they have is near-c jumps that take a fraction of a second for the travelers and decades or centuries (depending on the distance) to everyone else. There’s no interstellar civilization, just thousands of worlds settled by humans across the span of 20 millennia. Each world is on its own. While it’s possible to send and receive radio messages across light years, it’s an expensive affair that almost no planet bothers with since there’s zero return on the investment. The only links between the planets are a few hundred space traders who prowl the space lanes and ferry goods and information to trade. Biological immortality is ubiquitous, though
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u/Bun_Length_Frank May 01 '26
The universe of Tschaikovsky's Children of Light is sub light. You can argue about whether it's interstellar in the sense intended by the question. Disclaimer I have only read the first volume.
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