This is different from asking which story,etc. had the most habitable worlds in the solar system. A habitable world is one where Humans can live without space suits and airtight enclosed communities with advanced life support systems.

A life bearing world is one where there is life. A life bearing world in fact and fiction could have life while still being instantly deadly to humans.

For example, it is speculated that there could possibly be liquid oceans beneath the icy surfaces of moons like Europa and Enceladas, and there might be life in those oceans even though humans would drown in them.

So what science fiction story, series, movie, tv show, etc.. had the most life bearing worlds in the solar system, even if they were not all habitable for humans?

  • I'm not sure that your distinction between "life bearing" and "habitable" makes sense. If the presence of oceans in which people could drown on Europa and Enceladus makes them uninhabitable, shouldn't the presence of equally drownable oceans on earth make it uninhabitable? The fact that you might die there doesn't mean it isn't habitable. – Wad Cheber Jul 4 '15 at 22:01
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    In fact, earth has more things that can make you dead than any other planet or moon in the solar system. The other planets don't have stuff like tigers and rattlesnakes and Ebola and nuclear bombs and knives and sharks and food poisoning. Other planets have one or two things that can kill you- the atmosphere, the temperature, the lack of food and water, etc. Earth is crawling with things that exist specifically to murder you. This would suggest, according to your own reasoning, that the earth is in fact the LEAST habitable planet in the solar system. – Wad Cheber Jul 4 '15 at 22:04
  • My "no research off the top of my head" answer would be an old Nickelodeon show called Space Cases. They had characters native to Earth, Titan, Uranus and Mercury. en.wikipedia.org/wiki/Space_Cases – Alarion Jul 4 '15 at 22:09
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    Just looking at your example about the oceans on Europa and Enceladus, yes, you could drown in them, but that is also true of the oceans on earth. However, on earth, you also have to deal with sharks, killer whales, venomous jellyfish, barracuda, leopard seals, and a million other deadly sea creatures. One of the most venomous animals in the planet is a tiny sea snail. Earth has the same deadly forces as other planets do, but we have a huge number of extra threats surrounding us at all times, which don't exist elsewhere. This place is incredibly hostile to life, because life thrives on murder. – Wad Cheber Jul 4 '15 at 22:12
  • We are talking about THIS solar system, right? I assumed so, but I'm not sure. – Wad Cheber Jul 5 '15 at 0:17

It would be hard to beat a universe in which every world, without exception, is life-bearing. Indeed, it seems to be tacitly assumed in a lot of old pulp sci-fi that every planet, moon, asteroid, and comet is inhabited by some sort of critters. This assumption is made explicit in the 1958 novel The Million Cities by J. T. McIntosh. The following quotations are from the magazine version (Satellite Science Fiction, August 1948, available at the Internet Archive); I don't know if anything was changed when it was expanded for book publication.

"Long ago scientists estimated mathematically that the chances of life occurring on any planet were . . . I don't know, umpteen thousand to one against. But the answer here is that something so unlikely wouldn't have happened on Earth either. As a matter of fact, no planet which can support life of any sort--and you'd be surprised how hot or cold they've got to be before they can't—ever lacks it.

"Life either forms on the planet itself, or gets brought from somewhere else. Of course, I don't mean human life. I don't even mean insect or reptilian life or bacterial life. Sometimes it's life in so rudimentary a stage you wouldn't recognize it as life. But always there's life. And any life that ever forms moves towards intelligence. And as a species gets more intelligent it propagates. It kills off its enemies, stops killing itself and stops anything else from killing it."

[. . .]

"There are Martians?" Jon demanded quickly.

"Of course. And Mercurians and Venusians and Jovians and so on."

"Are the Martians intelligent?"

"Yes, they're older than we are by a good many millions of years."

"Why hasn't there been radio communication?"

"There will be some day. But the Martians don't matter at the moment as much as the Lunarians."

"Are there people on the moon?"

"Not people. Not even intelligent creatures. And not very many of them. I'll come back to them in a minute."

[. . .]

"Get that to begin with," she said. "Every planet above absolute zero and below the temperature of boiling rock develops life sooner or later. Some that are at absolute zero now or hotter than boiling rock are inhabited by races which evolved before it got so cold or so hot, races that had the brains to survive when conditions changed.

"Now can you answer my question? Why has Earth, in all these thousands of years, had no visitors from Rigel, Capella, Sirius, Procyon?"

[. . .]

"You mean we're not allowed to leave Earth?"

Jia smiled. "That's exactly it. It works both ways. Every world belongs to the creatures who evolve on it. That goes for the moon, where the only living things are tiny, brainless creatures that live on sunlight. It will be millions of years before they develop what we'd call intelligence—if they ever do. But the moon's their world, and we're not allowed to take it away from them."

  • Yes, but unless the person who says every world has some form of life has some evidence, it is merely an opinion within the story. And if Humans are not allowed to leave Earth in that the story, they will never know if that opinion is correct or there is some other reason to forbidd them to leave Earth. Since there now seem to be tens of other semi or fully intelligent species on Earth, and there is no proof of any life, let alone intelligent life, on other worlds, perhaps Humans should be forced to leave earth and forbidden to return instead of forced to stay on Earth. – M. A. Golding Jul 5 '15 at 3:08
  • "It would be hard to beat a universe in which every world, without exception, is life-bearing. Indeed, it seems to be tacitly assumed in a lot of old pulp sci-fi that every planet, moon, asteroid, and comet is inhabited by some sort of critters. " - So you say, but as my own answer says, the largest number of life bearing worlds in the solar system I find in any series I am familiar with is ten. As I remember, stories with life on asteroids or comets were rare, and no more than ten moons were commonly shown to have life. – M. A. Golding Jul 5 '15 at 3:23

At least 12 (maybe 13 or 14) life-bearing worlds in the Solar System are visited or mentioned in the Gerry Carlyle stories. Created by Arthur K. Barnes, Gerry "Catch-'em-Alive" Carlyle is a beautiful interplanetary huntress who roams the Solar System acquiring exotic beasts for the London Interplanetary Zoo. She was featured in her own series of stories, and in a couple of crossover stories with Tony Quade, a character created by Henry Kuttner.

Five Gerry Carlyle stories ("The Hothouse Planet", "Satellite Five", "Siren Satellite", "The Seven Sleepers", and "Trouble on Titan") were published as the fix-up novel Interplanetary Hunter by Gnome Press in 1956; this was reprinted in paperback by Ace Books in 1972. These five stories and two more, "The Dual World" and "The Energy Eaters", are available for free at Critical Press Media.

Earth: inhabited, of course; Gerry Carlyle's home base:

She was dressed in mirror-polished high boots, riding pants, and polo shirt open at her tanned throat; these were the badges of her profession. For this was the New York office of Gerry Carlyle, grim huntress of fierce monsters on the inhospitable planets of the solar System, serene and gracious hostess now.

Mercury, Venus, Saturn, and pretty much everywhere (the "barren rock" they just landed on is Titan):

“Isn’t it incredible how persistent and unconquerable life is? We find it everywhere, under the most terrible conditions—the inferno of Mercury, the stewpot of Venus, and crawling under tons of pressure on Saturn. Now even on this barren rock, a great civilization evolved. Those Arrhenius spores sure got around, didn’t they?”


“Every newscast from the Moon, for the last six hours has had something about these jiggers. From Mercury, the guy says.”

Gerry quirked up an eyebrow. “I've scoured Mercury's twilight zone twice for life-forms; I've brought back the only living things ever seen by man on the surface of Mercury. I even went over the dark side once.”

“These animals come from Hotside.”

Venus, the setting for two of the stories:

Strike's eyes clouded. There was truth in Ransom's remarks. Hunting for the strange little creatures called Murris never had resulted in anything but trouble since the day Sidney Murray, co-leader of the first great Venusian exploration party, the Cecil Stanhope—Sidney Murray Expedition, first set eyes upon them.

Mars, Mercury:

She remembered now that, during one of her earliest trips, she had discovered a microscopic Martian spore that in some respects resembled Von Zorn's Mercurian importation.

Venus, Jupiter:

“Oh, is that so?” Gerry snapped. “Hollywood on the Moon. Nine Planets Films, Incorporated. The biggest bunch of crooked fakers in the System. They duplicate the life-forms I've captured at the risk of my life—Venusian whips, Jovian thunderdragons. And how do they do it? They make cheap robots. Radio-controlled robots at that. That's what gets in my hair, Tommy. I take all the risks, and they grab the credit and the cash.”


Strike began to have a nagging little premonition. More closely than ever, he watched the ceremony. Gerry, as had been agreed upon beforehand, was to make public her selection of the monster whose capture was necessary for victory. She named the dermaphos of Saturn, so-called because, according to Murray—the great pioneer explorer whose books were standard texts in every college--the dermaphos’ hide glowed with a faint phosphorescence. Kurtt, much to Strike’s increasing uneasiness, was not in least taken aback. Not much was known about the dermaphos, except from the writings of Murray and one or two other explorers. They described it as a relatively large creature and rather rare. Confident in the ability of her own crew to surmount any and all obstacles, Gerry had purposely chosen a beast that would be difficult to capture. But Kurtt was nodding and smiling, perfectly agreeable. It was a curious phenomenon, and it gave Strike considerable to think about.


Here Nine Planets Films, Inc. had its headquarters. Here the interplanetary sagas were plotted and planned by ingenious script writers. Here the technical experts consulted, the experimental labs created robot-life-forms and artificial other-worldly conditions. And here Von Zorn ruled like a czar. He was the President of Nine Planets and Tony Quade was his ace man. When Von Zorn was in a spot, when experts said a picture couldn't be canned, he sent for Quade. And Quade had always proved the experts wrong.

Quade was the one who got the first four-dimensional films ever made. He was the daredevil maniac who captured the spectacularly deadly Plutonian life-forms on celluloid. He even shot the great Martian Inferno, the hottest SRO grosser in years. Against her will and without her knowledge, he had once filmed Gerry Carlyle. After Gerry Carlyle it was only a step to a comet.

Though Quade was worried, he didn't show it.


The Hyclops, native to Ganymede, stands more than twelve feet high, is terrifyingly covered with hair, and has four arms. Its three one-eyed heads bear murderous fangs that protrude from a slobbering, loose-lipped mouth. “Get the eyes,” Gerry yelped, scurrying to one side. “We haven't any super-explosive bullets, but—aim at the eyes.”

Jupiter V aka Amalthea, home of the fire-breathing cacus:

“What this strange creature, so inimical, may be, we can only conjecture, aided by fragmentary notes of space farers who passed briefly in proximity to Satellite Five, and by telescopic observations from Io, the next Jovian satellite outward. These give us a curious picture. Four things we can say about it. The thing is somewhat saurian or wormlike in appearance, low on the evolutionary scale. It seems to be of a sluggish nature, which would be natural considering what a limited supply of energy-building food elements there must be on Five. Not more than one has ever been seen at a given time. And—believe this if you can! The monster breathes fire! Literally!”


She opened up the volume on Saturn and its satellites, turned to Titan and quickly flipped the pages. Titan was extraordinarily rich in minerals of almost every conceivable type. Only transportation costs prevented mining there. Also, its atmosphere was breathable, its temperatures apparently not lethally extreme.

More remarkable, according to Murray’s writings, there was civilized life on Titan. The cities there had been built with an amazing genius for metalworking. But Murray’s notes were sketchy on the subject. It seemed that the inhabitants of Titan were few in number and difficult to communicate with, though quite friendly.

The fact that highly evolved life existed on the satellite was not startling. Advanced civilizations had been discovered in at least three other places in the System. If any nomadic tribe, gifted with the ability to work in metals, had wandered in from outer space and decided to locate in the Solar System, it was only natural for them to select Titan and its wealth of ores.


His voice trailed off as he saw Gerry staring wide-eyed past him. He turned. Thirty yards away, something new had been added to the landscape.

A five-foot high Thing covered completely with dark, coarse hair, tapering to a blunt point from a broad base. It somewhat resembled a blackly furry bishop, strayed from a gigantic chessboard. The Thing stood utterly motionless in the grayness, as they watched. Though apparently without features, it somehow gave the feeling of watching them in intense curiosity.

Almussen's Comet (fictional):

“They're a decadent race. Ages ago they had an entirely different form, I don't know just what. They've lived on this comet for unimaginable eons. They evolved along lines totally alien to ours, reached the summit of their culture, and began to slide back. This barren body won't support much life. In time, only seven Proteans were left. They were highly evolved intellectuals, chained to this barren world because they hadn't mastered space travel. Know what they did?”

Mercury, Venus, Earth, Mars, Jupiter, Saturn, Pluto, Ganymede, Amalthea, Titan, Triton, and a comet; 12 worlds. Two more candidates, the Moon and an asteroid:

The Moon:

Quade lit a cigar of greenish, aromatic Lunar tobacco.

It is not clear if the "lunar tobacco" plants are native to the Moon. By the way, there is also mention of "Venusian tobacco":

It was taking place in the New York offices of the London Interplanetary Zoo, on the top floor of the tremendous Walker Building. The suite was built of the finest modern materials and equipped with all the comforts science could devise. Vacuum-brik walls shut out noise. There were mineral fluff insulation, Martian sound-absorbent rugs, plastic bodycontour furniture, air conditioning. The press of a button brought iced drinks or lighted cigarettes of aromatic Venusian tobaccos through a recess in one wall.

The rest of these examples are from Henry Kuttner's Tony Quade story "Hollywood on the Moon", with quotations taken from the (probably abridged) 1949 reprint. Gerry Carlyle does not appear in this story, but it's set in the same Solar System, and she is mentioned, so I guess it counts. Here is more about that lunar tobacco (Startling Stories, July 1949, p. 114):

Von Zorn took out a cigar, made from the aromatic, greenish tobacco grown on the Moon and cut it carefully. "I've trouble enough without you making it worse," he growled. "Our last Venusian picture is flopping and we invested over a million in it. That blasted Carlyle woman's blown it sky-high."

"Gerry Carlyle?"

"Yeah, the catch-'em-alive dame. We pay out half a million to the biological labs to create duplicates of Venusian animals and now there aren't any audiences because Gerry Carlyle's brought back the real thing." He lapsed into a stream of fluent profanity.

The Silver Spacesuit (on the Moon) serves a delicacy (presumably native) called Moontruffles (SS, July 1949, p. 112):

"Eh?" Quade stared, and then glanced up as a waitress glided up in her tiny gilded autocar. "I'm not hungry, thanks. Wait a minute. Yes, I am. I've got a long ride ahead. Double order of ham and eggs."

The girl looked shocked and made a feeble attempt to suggest Moontruffle salad instead but Quade waved her away and turned back to Gregg.

An old theory about lunar habitability (SS, July 1949, p. 111):

The Moon is egg-shaped. The larger part is turned perpetually toward the Earth but the smaller end is scooped out into a vast crater, whence volcanic activity in some long past eon had blown a fragment as large as the asteroid Vesta. Within this great hollow are an atmosphere, life, great buildings and studios—Hollywood on the Moon!

1036 Ganymed, an asteroid, spelled "Ganymede" in the story (SS, July 1949, pp. 111-112):

"Well, what can we do?"

"Use Ganymede."

"Jupiter's moon? It's too far."

"No, you sap, the asteroid Ganymede. It'll be at perihelion in a few days and that'll bring it within the orbit of Mars, close enough for us. We can't use Eros. After the ether eddy hits it there won't be any Eros. We'll have to put up a set at Ganymede's pole and film the explosion from there. It'll be a rush job but we can make it before the deadline."

And the natives are intelligent (SS, July 1949, p. 123):

"But—but—Ganymede isn't inhabited by intelligent life! Not over the eighth level, anyway."

"Sure it is," the agent interrupted. "This little fellow here is probably smarter than you are." He indicated the bouncer. "He doesn't look it, but he's just over the eighth level. Mr. Quade called me in and wanted an intelligence test made. And it turned out he was right.

"Ganymede is already inhabited by these jiggers—which are over the eighth level of intelligence—so the asteroid belongs to them and Washington says so. And I'll bet neither you nor Sobelin wants to buck the Government."

  • So the high score is now (07/05/15) 12 life bearing worlds in our solar system in the Gerry Carlyle stories by Arthur Barnes. – M. A. Golding Jul 6 '15 at 1:45
  • @M.A.Golding 13 if the "Lunar tobacco" is native to the Moon. – user14111 Jul 6 '15 at 23:50

Borrowing from my own answer to your other question along these lines:

One candidate would be the movie 2010: The Year We Make Contact (and the book on which it was based, 2010: Odyssey Two). At the climax of the story, Jupiter becomes a second star in our solar system, and its moons become planets. The unidentified alien race which caused this chain of events then sends a message to humanity:


The story ends with an image of Europa, now teeming with life. Although we don't know for sure that the other new planets (formerly moons) are life-bearing, the message clearly implies that this is indeed the case - we are told to "use them together... in peace", and it is hard to imagine how we could use planets that are not capable of nurturing life.

Jupiter has at least 67 moons at the most recent count, which could mean that there are now as many as 68 life-bearing planets in the solar system (Jupiter's 67 moons plus the earth).

However, we don't know how many of Jupiter's new planets are actually life-bearing. It is probably safe to assume that some of them are not viable. I don't know if the book addresses this issue, but the movie certainly doesn't. If we assume that half of the new planets are life-bearing, then the number of viable worlds would be about 34, including the earth. If a third of the new planets are life-bearing, the number of viable worlds is closer to 23, including the earth.

In any case, the number of life-bearing worlds in 2010: The Year We Make Contact/2010: Odyssey Two is probably quite large.

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    I doubt that Sir Arthur C. Clarke, author of the novel, ever believed that simply turning Jupiter into a sun would be enough to make any Jovian moons habitable. No doubt Clarke expected his readers to assume that the aliens were giving Humans permission to terraform Io, Ganymede, and Callisto with imported atmospheres, which will now be about warm enough. The other moons could be mined like asteroids or have solar/Jovian power stations. – M. A. Golding Jul 5 '15 at 0:53
  • @M.A.Golding Does that make my answer unacceptable? I'm not sure what you are looking for here. – Wad Cheber Jul 5 '15 at 0:59
  • Wad Chebber - I am looking for answers like Story A had five life bearing worlds in our solar system, story B had ten, story C had 14, and so on until someone comes up with a number which seems likely to be unbeatable. – M. A. Golding Jul 5 '15 at 1:18
  • It's been a long time since I've read them, but I'm pretty sure the books never mention any non-Terran life in the solar system besides that on Europa and Jupiter (the latter being destroyed for the sake of the former). – jwodder Jul 5 '15 at 3:36

I don't think that 2001: The Year We Made Contact should count as the most life bearing worlds in our solar system. Arthur C. Clarke, author of the novel that the movie is based on, was a great science fiction writer and wouldn't assume that his readers believed that simply turning Jupiter into a sun would be enough to make all or any Jovian moons habitable.

Instead he would think his readers would assume that the aliens were giving Humans permission to terraform Io, Ganymede and Callisto. We could bring in breathable atmospheres from elsewhere and then enjoy the warmth provided by Jupiter transformed into a star. The dozens of other Jovian moons could be mined like asteroids or have power stations turning Jovian light into electricity.

As an example, E.E. Smith's Lensman series had native intelligent and other life on Venus, Earth, Mars, and Jupiter, and Pluto was colonized by frigid-bodied Palainians, making five life bearing worlds, one definitely not habitable for Humans.

In another example, Stanley G. Weibaum's stories had native life on Venus, Earth, Mars, Io, Europa, Ganymede, Titan, Iapetus i think, Uranus, and Pluto. Most of those worlds were at least slightly semi habitable for Humans, except Iapetus which was only mentioned and definitely Pluto. that makes nine or ten worlds, with about ten semi or fully intelligent species.

So I guess the correct answer would be a story or tv series with at least eleven (non terraformed) worlds with native life in the solar system.

On 07/05/15 the high score is now twelve life bearing worlds in our solar system in the Gerry Carlyle stories by Arthur Barnes.

That should be compared to this site:


which claims that a double star system could have as many as sixty planets habitable not just for life in general but also more specifically for Earth Humans in particular - no doubt such systems would be extremely rare even if they may be scientifically possible.

And of course it may be possible in the future to build countless millions of ARTIFICIAL space habitats out of asteroids, comets, Trans Neptunian Objects, and small moons.


Red Dwarf: Better Than Life describes how the whole solar system has been systematically terraformed. The implication is that every planet is (to a lesser or greater extent) liveable and that goes for many of the moons as well, potentially twenty or thirty accessible planetoids.

Delegates from all the planets and their satellites submitted tenders to lose the contract.

The Mercurian delegation pointed to their solar-energy plants, which provided cheap, limitless energy for the whole system.

The study group from Uranus hinged its case on its natural stores of mineral deposits. Jupiter and its moons relied on their outstanding natural beauty.

Neptune built its case on famous planetary architecture - it had been terraformed to the highest specifications.

Saturn's rings, a massive tourist attraction, made that planet safe, and its network of moons, though often seedy and downmarket, generated a lot of business, merely because of their position along established trade routes.

Mars was the safest of all, because it was home to the wealthy. It was the chicest, most exclusive world in the planetary system, handy for commuting to other planets, yet far enough away from the riff-raff to be ideal for the mega-rich.

Venus took the Martian over-spill - the people who wanted to live on Mars, but couldn't quite afford it. Venus was full of people who wanted to be Martians, so much so they often quoted their address as 'South Mars' or 'Mars/Venus borders.' Still, it was a fairly wealthy planet, and the Venusians constituted a powerful political lobby.

And so it became a straight battle between Earth and Pluto. The Plutonian delegation made rather a weak case, drawing attention to their planet's erratic orbit and its position on the edge of the solar system.


It seems to me that Firefly had quite a few habitable worlds, each with several habitable moons, all withing a single solar system. The characters were always making reference to worlds and moons they had not visited before.

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    but does it really have the most? how many do they refer to? this is a very incomplete answer. – phantom42 Sep 22 '15 at 2:47

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