Suppose for the moment that one was a science fiction author and was trying to imagine a plausible setting in which a multitude of inhabited worlds were within easy, quick reach. Further suppose that one did not care to discard relativity, but likewise was not keen on a setting where time dilation plays a significant role. What is one to do?
How many authors have tried to come up with settings that meet all these demands? More than you’d expect.
Old-time SF had the luxury of ignoring unpromising scientific data about the Solar System (which at that time was sparse, and to some degree conjectural). Authors like C. L. Moore and Leigh Brackett could freely imagine planets and moons that had Earthlike atmospheres and ecologies, not to mention exotic civilizations. Space probe info on the real conditions in the Solar System have made such speculations implausible. But… an author could set their story sufficiently far into the future that all the terraformable planets have been terraformed.
Examples are not readily coming to mind (I am sure I will smack my forehead when the comments start pouring in). Many authors have written about terraformed planets, but usually of just one planet, not all of them. Liz Williams’ Banner of Souls features a terraformed Mars, for example, while Pamela Sargent’s Venus series focuses on a generational quest to reshape Venus. Paul Preuss’ The Shining Ones provides an interesting edge case in which aliens reshape multiple worlds (Venus and Mars) to their liking. However, their program is far enough in the past that the terraforming has failed. Neither world is habitable when humans arrive in the modern era.
Another approach is to accept the worlds as they are and focus on smaller-scale efforts to exploit them. This at least would provide communities to visit—potentially a large number of them. Authors have located such communities on many bodies of the Solar System. See, for example, Clarke’s rather odd, hard SF yaoi novel Imperial Earth, in which various moons and planets are now home to self-contained, sealed cities.
Alternatively, authors might turn to a concept that was particularly popular in the 1970s and 1980s: turning the dead matter of moons and asteroids into orbiting space habitats, of which physicist Gerard K. O’Neill was an avid and convincing proponent. Or they could combine the strategies, as seen in Paul J. McAuley’s Quiet War series, which begins with the great powers of Earth eyeing the diverse communities of the outer Solar System. It would be nice to say that the old nations of Earth were inspired to embrace Infinite Diversity in Infinite Combinations…it would also be a lie. Instead, a rather grim tale of relentless cultural purification ensues.
An approach which offers the benefit of even smaller-scale efforts is to forget world or city-sized endeavors and focus on the human factor. If humans cannot survive on other worlds, alter the humans so that they can. The most striking example is probably John Varley’s original Eight Worlds setting, in which null-suits—form-fitting force fields combined with personal life-support equipment—enable otherwise naked humans to stroll about on the surfaces of extremely hostile worlds (such as Venus or Mercury). Null-suits do diddly-squat to protect wearers from the effects of gravity, however, so characters must avoid falling into the Sun or close encounters with black holes.
One of the odder solutions involves a huge spoiler so I will put the identity of the book series down in a footnote, where readers may choose to ignore it. In a future dominated by Islamic powers (a future that seems to have been based on a Classics Illustrated adaptation of the tales from the Arabian Nights or perhaps a screening of 1921’s The Sheik; a future that is utterly unrepresentative and false), one particularly visionary autocrat becomes frustrated at the inherent communications lag between star systems imposed by relativity. The solution? A massive engineering project to move the sunlike stars near the Sun into a much smaller volume. Points for ambition, although I do wonder how stable planetary orbits would be if all those stars were crammed together.
Finally, one can simply provide the illusion of rapid interstellar travel. Karl Schroeder’s Lockstep is one such book. In this setting, unable to avoid time-consuming voyages between distant worlds, the worlds agree to spend most of their time in suspended animation, waking according to a pre-arranged synchronized schedule. Years may pass in reality—but not to the citizens of the lockstepped worlds.
These are, of course, only a few of the possibilities. No doubt many of you can think of options I overlooked. Comments are, as ever, below.
In the words of fanfiction author Musty181, prolific book reviewer and perennial Darwin Award nominee James Davis Nicoll “looks like a default mii with glasses.” His work has appeared in Publishers Weekly and Romantic Times as well as on his own websites, James Nicoll Reviews (where he is assisted by editor Karen Lofstrom and web person Adrienne L. Travis) and the 2021 and 2022 Aurora Award finalist Young People Read Old SFF (where he is assisted by web person Adrienne L. Travis). He is a four-time finalist for the Best Fan Writer Hugo Award, and is surprisingly flammable.
S.M. Stirling’s Lords of Creation duology has Mars and Venus having been terraformed in the past by unknown aliens, with interesting hijinks ensuing as Earth discovers what’s up on its fellow planets. Many nods to past planetary romances.
Christopher Hinz’s Paratwa series has Earth (almost totally) extinct in a bionuclear apocalypse and surviving humans in a couple of hundred O’Neill colonies surrounding Earth — so it looks like someone did write about your hypothetical ;)
Not a book, but the setting of Firefly is in a multi-star system with several habitable or terraformable (is that a word?) planets and moons, where the remnants of humanity migrate using generation ships after destroying Earth.
Like Lockstep, Charles Sheffield’s Between the Strokes of Night (1985) provides the illusion of FTL. It assumes a cryogenic-related state of consciousness, “S-State”, that runs thousands of times slower than normal human consciousness. Thus the subjective time to travel between suns is only a few months instead of thousands of months.
The Mote in God’s Eye tells us that there have been wars plural that have rendered either Mote Prime or the asteroid habitats uninhabitable, but never both at once.
An idea that someone must have used by now: STL spaceships + engineered immortality/extreme longevity.
Also, I’m rather surprised you didn’t mention Ursula K. Le Guin’s Hainish universe with its NAFAL ships (and, to be fair, ansibles).
The Hainish books embrace time dilation, whereas I was looking for ways around it.
@5/6: Niven has a short story where it develops that the mysterious aliens use STL travel plus time travel to mimic FTL (yes, this is aphysical). Left unsaid is whether they use low berths or are just very patient.
Doesn’t Ring World address this as well? Sure Louis Wu used FTL to get there, but once he arrived traveling to the various mimiced worlds was pretty fast. As mentioned above any Dyson Sphere would have so much room that cultures could become significantly different by moving far enough away that travel times could approach months. Sort of like the New World and old Europe.
Iain M Banks “Against a Dark Background” has everything that can be terraformed already terraformed. Or something-formed anyway as it’s not our solar system…
What about the Honorverse? Most worlds were settled by generation ships, up to point where wormhome travel was discovered and popularized.
David Weber, in his Honor Harrington series, postulated Generation Ships that settled worlds over Millenia, before the Nexus wormholes were discovered that permitted fast travel between wormhole openings.
Stargate. Nuff said.
Harry Harrison’s A World of Difference held that Mars didn’t make the cut with respect to human habitability, so let’s just set the story in the timeline where the fourth planet was a more massive, habitable (and inhabited) Minerva.
“Clarke’s rather odd, hard SF yaoi novel Imperial Earth”. There’s a meme picture of a cartoon person raising their finger and opening their mouth to object … but the next panel is them lowering their finger and looking frustrated + angry. … oh, there’s a copy.
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Ted Sturgeon’s “Time Warp” (in the running for the least memorable title in existence) has a space drive that goes “forward in space, backward in time” – you go X lightyears forward, you drop back X years, it all evens out. At least, most of the time.
13: Turtledove, not Harrison.
Unless someone mentioned it and I missed it, I’m surprised that Corey’s The Expanse series wasn’t mentioned. It does take weeks to go between colonies in the Belt, but not an insurmountable amount of time. Then the Ring Gates get involved, and it gets messy.
In principle you can stick lots of planets in a habitable zone around a sufficiently luminous star, but you run into issues of stellar lifetime (Jack Vance’s Rigel Concourse) or stability (Betelgeuse – luminosity variations of a factor of 2 aren’t going to be good for the climate).
@12: Stargate has multiple forms of FTL, including the eponymous stargates. Fun show but little about it was scientifically plausible.
@5 There is “A Deepness in the Sky” by Verner Vinge (Zones of Thought book 2), where STL is used along with cryosleep.
You mention Karl Schroeder’s Lockstep, but Schroeder actually plays with this idea in many of his novels. In his earlier novel Permanence, he also supposes that there are maybe ten small, brown dwarf stars floating in the interstellar void for every G-type star. This provides humanity with many places to live within a few light days or weeks of Sol.
Also in his novel Lady of Mazes, he describes a solar system in which trillions of humans live in millions of ring structures, (smaller than Ringworld, but larger than Halos). IIRC, the planets are terraformed and inhabited too, that is those planets that weren’t disassembled and used to build the large habitats.
Joe Haldemans “Forever War” does a really interesting job of exploring the timeline issues created by prolonged FTL travel.
It all depends on what “plausible” means. In John Barnes’s “Thousand Cultures” series, extreme/legendary/mythological cultures (ranging from unstable economic theories to moderns’ beliefs about ancient glories) were seeded on vaguely habitable worlds by sending genetic matter (and AI to birth and raise them) on slowships; then somebody discovers interstellar-capable teleportation, so the only delay is the time needed to get slowships with teleport booths to all the scattered colonies. One realistic touch: members of colonies that have recently survived the culture shock of being introduced to a non-monomaniacal universe are called on to help new contacts cope with ~reality — sometimes this works, and sometimes it spectacularly doesn’t.
Alastair Reynolds’ Revenger and sequels feature a very old, very far future solar system where all the rocky bodies have been used in the distant past to build a cloud of habitats of different kinds and sizes. Travel between worlds is by lightsail ships. There are alien wonders, ancient mysteries and pirates.
Also from Ringworld, the Klemperer Rosette, since the habitable band is narrow, put all the planets in the same orbit, around their common centre of gravity.
I see that I was unclear. When I said
what I meant was imagine that an author wanted to write about a setting with lots of worlds with short travel times between them, something compatible with the laws of physics as we currently know them, including relativity, but did not want time dilation to play a role. So, no NAFAL starships, no FTL drives, no planet to planet teleportation.
Could we… not start using “yaoi” in English to blanket describe narratives that include queer men? Not only is it a word for manga (i.e., Japanese comics, specifically) that include MLM/MSM relationships, but it’s pretty much by definition written by hetero women for the consumption of hetero women, with a focus on highly pseudo-gendered top/bottom dynamics between young men or boys. Even the etymology is homophobic: ヤマなし、オチなし、意味なし [yama nashi, ochi nashi, imi nashi], literally, “without climax, point, or meaning,” indicating that it exists purely for the women writers’ fetishistic entertainment. Like, imagine describing, idk, Rubyfruit Jungle as “girl-on-girl” or any other category of “lesbian” porn created by and marketed to hetero men. That’s pretty literally what you’re doing here.
Clarke was a queer, most likely gay English man writing in the English language who included gay and bisexual men in his works as a matter of realistic representation, not “othered” fetishization. That is not “yaoi.”
ISTR that in Peter Hamilton’s The Naked God (the third of the Night’s Dawn trilogy) the titular deus ex machina rearranges the existing human worlds Into a Klemperer rosette to allow rapid STL travel between them, taking a leaf out of the book of one of the older and more advanced alien civilisations humanity has come into contact with.
Mind you – scientifically plausible, maybe not so much
Chitnis @2: My plot concept for the setting of Firefly is that the image of the system shown at the beginning of the movie is accurate, and that humans found it that way when they arrived rather than doing the terraforming themselves. (If humanity had that kind of technology, it would have been feasible to stay in our own solar system!) The system is unstable in geological time, and to all intents and purposes could not have developed that way naturally. So the government is extremely concerned that the beings who did that work may be coming back, and created people like River as weapons against them.
@doug Jones:
Please explain how getting squirted from world to world in a few seconds does not qualify as FTL?
Not all that different from the notion of a jump drive, truth be told.
I enjoyed the old E E “Doc” Smith “Venus Equilateral” stories. Not FTL but communication faster than light and very entertaining and creative engineering. I appreciated the mention of “Expanse.”
awwwwwwwww….
OK, how about Marko Kloos’s Palladium Wars books? There are enough habitable planets in one solar system to have had something analogous to World War II; now people are trying to pick up the pieces. I suppose even this is stretching, as there is no explanation of how so many planets are habitable; they weren’t placed in a rosette, and we aren’t even given the handwaving that they’re at such a distance around such a powerful star that several planets could fit in the habitable zone without interfering with each other. (Yes, big stars are thought to burn out quickly — but ISTM we’re given that these are worlds colonized by Earth humans rather people-like-us who evolved there.) (I’m also unconvinced that moving planets into a rosette doesn’t take as much handwaving as FTL etc.) Good stories, though; I’m not a fan of MilSF in general and picked up the first of these only on Walton’s rec, and am now waiting impatiently for #4.
My Astropolis books used STL combined with extreme longevity / altered biological time (so a century might appear to pass in a second) to make interstellar travel viable. That’s always seemed the most logical solution to me IRL. If one can solve the energy problems of travelling that far, why not the biological ones too?
Niven’s Integral Trees is kinda similar: Slower-than-light only setting. Vast gas torus around a star, with breathable air, produces a vast free-fall habitable volume in one star system. I don’t know how realistic the science is, but no FTL.
32: George O., not E.E. George was the one who ran off with John Campbell’s wife.
Hal Clement created a fictional planetary system containing several habitable worlds in his 1960 monograph “Some Notes on Xi Bootis”. If I remember correctly, one of the inspirations for writing it was that at the time, advances in scientific knowledge were rendering stories with habitable versions of Mars and Venus untenable, and he was offering this as a substitute for writers who wanted their characters to travel between similar planets without having to resort to FTL. I don’t know if there were any published stories that actually used Clement’s scenario.
@5/sturgeonslawyer:
The “Astropolis” cycle by Sean Williams and Shane Dix (Saturn Returns (2007) et seq.) comes close: post-humans can adjust their biological tempo: slow for boring space journeys, fast for combat. (The narrative does not address the mechanical problem of actually moving at a slower tempo, when gravity is unchanged and mid-step is an unbalanced posture.) I don’t recall if travel is specifically STL or just slow-FTL in which trans-galactic journeys consume years. (Haven’t got that book on my shelf anymore to check: Williams and Dix do big ideas, but the stories aren’t fun re-reads.)
Posthumans in this galactic civilization exhibit a range of abilities like “hundreds of thousands of years old” or “duplicated across multiple bodies who periodically meet to swap memories.”
“If humanity had that kind of technology, it would have been feasible to stay in our own solar system!”
I joke that the ‘Verse was settled by the B Ark. This is why there aren’t any Chinese people: they’re back on a clean and healthy Earth.
Perhaps more plausibly, the migration leaders might have done some Year Zero re-writing of history.
@37: As discussed in Alec Nevala-Lee’s “Astounding”
Of course, the Gundam mega-franchise is almost* entirely restricted to our solar system and makes use of a myriad of space habitats (using both Earth-moon and Sun-Earth Lagrange orbits), and (on only one occasion) a successfully terraformed Mars (there was also an unsuccessful Mars terraforming mission, which took long enough for the colonists to be forgotten and interpreted as aliens by the time they returned to “invade” Earth).
(* The exceptions are 00, which ends with First Contact and the [post-script] development of wormhole drives, and Build Divers, which comes up with a. . . creative solution to interstellar contact, involving fully-immersive VR, [accidental] brain uploading, and alien-made nano-fabricators.)
I’d like to throw Martin A. Saunders ‘Insurmountable Odds’ into the mix… While the novel isn’t hard sci-fi, the setting is set 20,000 years in the future in an (spoilers) engineered Globula Cluster outside the long abandoned Milky Way. Various FTL exist, wormhole gateways, g-drive and Breach drives, and they are just rolling out ship mounted wormhole generators, all these tying thousands of star systems together. Combined with the qNet for instantaneous real-time networks regardless of distance. I’d like to live there… Sigh!
Samuel R. Delaney’s “Trouble on Triton”, an unforgettable read set on a terraformed Triton.
Joss Whedon’s short-lived but fan-beloved 2002-2003 TV series “Firefly” was set in “the ‘Verse”.
Quoting one of its fan wikis: “It consists of five main sequence stars, around which orbit seven protostars, seven gas giants, three separate asteroid belts, seventy-five planets, and one hundred forty-nine moons.” All this in a disk with a diameter of about 400 AUs (for comparison, Neptune is about 30 AUs from the Sun)
This allowed travel between its many Earth-like planets and moons (many terraformed) quick and easy enough to support its space-operatic plot, without resorting to warp drives, wormholes, or similar scientifically implausible means. Its fictional engineering played fast and lose, featuring spaceships with artificial gravity and spin-y engines allowing them to dispense with carrying reaction mass, the ‘Verse itself was delightfully plausible.
Don’t wormholes count as semi-plausible (and have been used by many SF writers, including Stephen Baxter, Lois McMaster Bujold, Peter F. Hamilton, etc)
Spanish SF writers Javier Redal and Juan Miguel Aguilera wrote a couple of novels positing that at some point in the future the solar system is swept away by a (slowly) passing globular cluster, so a few million years later humanity has expanded through it. The cluster, called Akasa-Puspa (“A Flower in the Sky”) is similar to the real world Omega Centaury: likely the remnant of a cannibalized dwarf galaxy, with a very high density of stars (at an average distance of only 0.1 ly) and a mixture of old and young stars (so they are not all low metallicity).
There’s no FTL; they use (IIRC) fusion reactors, and travel between neighbor solar systems takes years. They mostly do commerce with non-perishable goods via a robotized system akin to the proposed Mars cycler project.
Michael Flynn’s shared universe, especially the Spiral Arm books, suggests that there are perhaps “rivers” in the universe wherein the speed of light is magnitudes higher. It’s impossible to travel faster than light, but if the speed of light is higher between these two stars, then you can travel between them quickly.
46: Wormholes appear to depend on exotic forms of matter that while not necessarily ruled out by the laws of physics don’t seem to actually exist.
While perhaps a bit young adult, and not overly concerned with technological discussion compared to some of the discussed settings, Pierce Brown’s Red Rising does indeed have our solar system terraformed and colonized to a wide extent. The necessities and consequences I will leave to curious readers as it is one of the major subjects of the series.
And even with the exotic matter, wormholes raise relativity/causality issues that most authors handwave away.
Kim Stanley Robinson’s Mars trilogy has a plausible and detailed scenario for terraforming Mars. Some of Robert Heinlein’s best stories are set in a future where each planet in our Solar System has given rise to intelligent life. O’Neill cylinders are one of my favorite options. There is enough material in the asteroids of our solar system to build O’Neill cylinders for a human population of trillions around our one star. What would that future be like?
Peter Watts’ Blindsight includes a genetically engineered vampire.
I think it’s worth mentioning Terry Pratchett and Stephen Baxter’s Long Earth series here, although technically no one travels to other planets but instead alternate versions of Earth in parallel universes. However, those alternate worlds diverged from our own long enough ago to be different at the geological level, and are essentially alien planets in their own right (for example, none of them are found to be home to populations of other Homo sapiens before settlement). Blueprints released onto the internet allow people to cheaply build small devices that let them “step” between these Earths, most of which are habitable. The plausibility of traveling to other universes is debatable, considering we don’t even know if they exist, but at least it doesn’t violate relativity like FTL or lead to time mismatches like time dilation.
@46/49/51: ISTR that most of the calculations about wormholes conclude they would have miniscule diameters, such that anything larger than a microbe would come out the other end as a very long stream of protein sauce. Has anyone been following recent speculations?
I’m surprised that no one has mentioned Dan Simmons’s Ilium and Olympos, set on Earth, in Earth orbit, on Mars, and (briefly) Europa and Io. As I have a background in classics and medieval studies, Simmons has always appealed to me for the way he weaves his amazing love and knowledge of literature into his science fiction. Considering how little most of us understand our technology these days (the days when an enthusiastic amateur could pretty much understand the devices around them are gone, though still within living memory) I’d say Simmons’ portrayal of post humans is perhaps plausible, if somewhat optimistic. There’s a lesson in there about getting too immersed in your entertainments too.
@12: THE Doug Jones?
@54, If we are allowing The Long Earth, we might also include Greg Egan’s The Book of All Skies.
Charlie Stross has two novels that take place in the same setting that work here. Saturn’s Children and Neptune’s Brood take place in a future where humans have died out and the solar system, and later interstellar colonies, are populated by various robots. Interstellar travel is StL but the robots are able to slow down their perception of time for it, or broadcast their code to a new body.
Nathan Lowell’s Tales of the Solar Clipper world