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All Planets Are Earth-Like

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Not Earth. But close enough.

Qui-Gon: We're going down to the planet. What's it like?
GM: Err... Um... Earth-like?
Obi-Wan: Hmmm. Convenient.

That science fiction trope where planets fall into two categories: Earth-like (solid, with a human-breathable atmosphere and the same gravity, even if completely barren), and gas giants. And often, many of the gas giants have Earth-like moons. Even the most inhospitable of Single Biome Planets are not immune.

There is, of course, a certain subjectivity regarding the definition of "Earth-like". In some works, "Earth-like" means that a human being can walk around without a pressure suit and not die, but everything else (the presence of animals and plants, the weather, the gravity, and so on) might be vastly different. In other works, "Earth-like" means not only are pressure suits unnecessary, but a person can eat the plants and animals, drink the water, walk around in the gravity without a lot of effort, survive the weather, and so on.

Often justified by mentioning terraforming; series without terraforming invariably have many life-bearing planets that are perhaps more similar to Earth than most would consider plausible.note  Hell, even with terraforming, there still would not be too many planets in one solar system that might be human-inhabitable without some sort of huge sunlight-focusing and gathering apparatus in orbit, since the planets' distance to the sun seems to be the main factor. There are also some theories that an Earth-like planet would be the ideal type for (carbon-based) life (but again, this is just a theory). Additionally, even if a planet is terraformed, it still would look mostly the same as it did before, except a different color (if Mars were terraformed, it would still have its volcanoes and craters).

Can also be justified by The Law of Conservation of Detail. Most people are unlikely to visit a planet where they can't breathe, so Earth-like planets will tend to be the only places anything interesting is happening.

This frequently happens because at least half of science fiction shows are shot in British Columbia, which conveniently happens to be located on an Earth-like planet (Earth).

In live-action TV, this is inevitable, since creating a convincing alien planetary setting tends to require (a) a great deal of budget and F/X spent on a set that must be built very quickly and most likely will not be used again, and (b) any actors appearing in that setting to don costumes (also expensive, but more potentially reusable) which, if they are convincing full-protection envirosuits, will usually obscure the face and make acting more difficult. (See Rubber-Forehead Aliens for a reverse example of that problem.) Movies, animation and novels, less bound by time and budget concerns, have a somewhat better record, but even there the ability for human characters to see, be seen, and interact with each other without significant inconvenience tends to trump realistic assessment of xenoplanetary environmental conditions.

Of course, this makes it problematic if some species wants the resources of a certain planet and are not concerned about the fate of its inhabitants. You'd think that a universe full of uninhabited planets would be a wonderful resource for metals and other minerals, but no.

There's an actual astronomy term for Earth-like planets: Earth analogsnote 

See also Single-Biome Planet. Contrast Death World.

For depictions of planets in our own Solar System as more Earth-like than they are, see Once-Green Mars, Solar System Neighbors, Strolling on Jupiter and Venus Is Wet.

Since this trope is so ubiquitous, only Lampshade Hangings, subversions and aversions ought to be listed.


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    Anime and Manga 
  • Cowboy Bebop dodges the bullet when it comes to climate because every single solid object in the Solar System has been terraformed to one degree or another. What doesn't make sense is the gravity, which is Earth-like in every inhabitable space. The main cast grew up on three different planets/moons with wildly varying gravity (Faye and Ed from Earth, Spike from Mars, and Jet from the Jovian moon Ganymedenote ), but there's no signs of it affecting their physical growth, their living space has a single simulated gravity, and none have trouble acclimating when they move between planets.
  • In Daltanious, Planet Helios is rather Earth-like except the Heliosians have more advanced technology than the Earthlings. This leads some of them to view humans as primitive. Earl has a bad case of Racist Grandpa and is constantly told off for his callous attitude towards humans and other non-Heliosians.
  • In Dragon Ball Z, someone steps blithely out onto the surface of an alien world without even bothering to test the atmosphere, and is chastised for it. In fairness though, those someones tend to be Saiyans, half-Saiyans, a Namek, androids and so on — Krillin is the only human. All the main characters possess an array of superpowers too, and they only spend a prolonged time on two alien worlds in canon — Namek (which, since there are at least two Namekians living on Earth, presumably has a similar atmosphere) and King Kai's planet, which has some connection to the Afterlife, so atmosphere shouldn't really be a problem.
  • Gargantia on the Verdurous Planet outright inverts this. No one had found any habitable planets after Earth, and it is believed to have frozen over.
  • In Legend of the Galactic Heroes, all planets shown in the series could be mistaken for locations in Earth, with those of one faction more thematically attuned to 19th Century Germany.
  • Macross:
    • The franchise as a whole actually plays this a bit more realistically than others: while humanity and its allies have spread through nearly half the galaxy, they have only found a relatively small number of already inhabitable worlds on which to form permanent colonies. So while Earth-like planets do exist, they are very rare, meaning that some colonization fleets have had to resort to terraforming less hospitable worlds instead. To make things more complicated, many of the most desirable Earth-like planets are already inhabited by native intelligent life.
    • Macross Frontier:
      • Played with by the planet Gallian 4 that Alto and Sheryl go; it's described as a planet tidally locked towards the sun by a gas giant neighbor, making the extremities inhospitable.
      • The straight example is the Vajra homeworld, a Class-A planet virtually identical to Earth except for the three moons, and the Vajra nest/planet-sized rock formation that stretches up from gigantic pillars to form a huge ring around the equator. At the end of the series, Island 1 successfully lands on it, and the Frontier population start a new life there.
  • Lampshaded in the first Sound Stage of Magical Girl Lyrical Nanoha Striker S. When the cast visits Nanoha's homeworld, her students immediately express surprise on how similar it was to Mid-Childa.
  • Robot Romance Trilogy:
    • Voltes V: Played with in the case of Boazania. It's basically 17th-century France IN SPACE!, but the Boazanians are a Higher-Tech Species and thus have flying cars and advanced spacecraft. The Boazanians themselves are Human Aliens, except some have horns and some don't, and the ones that do look down on the ones that don't.
    • Daimos: Planet Baam is a Fantasy Counterpart Culture to Ancient Rome, and has gladiator colosseums and the like as part of it's culture. When it's destroyed, the Baam try to seek refuge on Earth due to how similar the planets are (in fact, Baams and humans are near-identical, except that Baams have wings). Later in the series, it's revealed that a small amount of Baam refugees have actually managed to assimilate into New Zealand and make it into their home.

    Comic Books 
  • Justified in Mickey Mouse Frontier Chronicles, as it's mostly set on Earth 32, a human colony so similar to Earth it was named after it as they do with their colonies closer to Earth in terms of environment. Even then, Earth 32 has a different year length.
  • Watchmen has a single superhuman in the world, Dr. Manhattan. He teleported to Mars just to have some solitude (with his godlike powers, he has absolutely no problem surviving there), and later returned and teleported Laurie to Mars as well. But, being a normal human, Laurie almost died of suffocation on Mars, before Dr. Manhattan remembered that other people need to breathe and created an air bubble for her.
  • Wonder Woman Vol 1: Diana visits just about every planet in the solar system, all of which prove earthlike with a breathable atmosphere. As does the moon, which even has a forest on it.

    Fan Works 
  • Invoked right at the start of With Strings Attached. After Varx offers to whisk Paul to another planet for adventure, Paul (who thinks he's dreaming) jokingly worries that he might be dropped on the Moon or some other inhospitable place. Varx assures him that they have an oxygen planet all picked out. Later, when the four go on the Vasyn quest, the three planets they visit are very Earthlike (one of them being an actual parallel Earth) but again, these were all picked out for them.
  • The Misfits (Warhammer 40,000): The impact that even minor differences from Earth that apparently habitable alien planets have becomes a major plot point. The planets of the Storm Ravens chapter's home system, Octalia, contain extremely low levels of potassium, so the government needs to import supplements from other star systems. This allows the Big Bad to incite a revolt by exposing the fact that the government has been skimming from the supplement fund and allowing the lower classes to suffer potassium deficiency.
  • Subverted in "Frostbite". Orvis II is technically Class M (Earthlike), but it's in an ice age right now and the site the away team is interested in is located in one of the glaciated areas. Biri points out that Bajor looked about the same five million years ago.
  • Played with in The Next Frontier. The Kerbals have two habitable bodies in their home solar system; the planet Kerbin and Laythe, moon of the gas giant Jool. That Laythe has liquid water at all much less an oxygen atmosphere is the product of a series of very improbable coincidences that surprised even the Kerbals themselves once they figured it out, so imagine their surprise when they send their first Faster Than Light starship to a nearby solar system, take some observations and find eleven planets and/or moons which have oxygen atmospheres. They draw the obvious conclusion: Terraforming. They're dead right, and boy, were they low-balling the number of inhabited planets...

    Films — Animation 

    Films — Live-Action 
  • Alien series:
    • It's an aversion if the human characters have to wear space suits (or at least respirators) when on the surface, as with LV-426 in Alien. However, the sequel plays it straight; this is handwaved by having a terraforming station having been set up on the planet since the events of the first film.
    • The planet Fiorina from Alien³ has breathable air but no inhabitants bar a few inmates on a mostly closed down prison. The fact that they terraformed somewhere like LV-426 implied that inhabitable planets were rare in this setting.
  • And in Avatar. The atmosphere has plenty of oxygen, it's just that we can't breathe the atmosphere because the composition of the other elements in the atmosphere more resembles the Earth during the Permian extinction — a whopping 18% carbon dioxide; trying to breathe that is like trying to breathe with a plastic bag over your head, and 0.1% hydrogen sulfide, which is extremely toxic to humans at even half that amount, being capable of damaging the mucous linings in the lungs. The Na'vi, along with every other land animal, are able to breathe in this environment despite it being hostile to the vast majority of earth-like life because the Pandoran life actually evolved there. Additionally, just about every plant or animal is inedible/toxic to humans. The low gravity is also why everything is so much bigger on Pandora; it can afford to be, on account of the lower gravity.
  • Averted in The Day the Earth Stood Still remake. Life-bearing worlds are so rare that the galactic races have agreed that no race must be allowed to destroy their world through pollution or war. Thus, if a race nears this stage, it must be "cleansed" from the planet, allowing this world to try again. Hence Klaatu's appalled reaction when the US Secretary of Defense calls Earth "our world," since the galactic races consider even the concept of a race owning their planet to be blasphemous.
  • Lampshaded in Galaxy Quest. When a character opens a shuttle door, another character points out that they don't know anything about the planet. Fortunately, there was indeed breathable air....

  • Averted in Lost in Space. It's mentioned that of all the planets found and examined by the space explorers, there is only one which can support human life.
  • Pitch Black: It's a desert planet, obviously hotter than hot. How it supports such an oxygen rich, earth-like atmosphere complete with rain is never explained.
    • The sequel features improbabilities such as Crematoria; indeed, the fact that the "most hostile" planet by Riddick's own account still sports a breathable atmosphere and earth gravity suggests that there may be no celestial bodies devoid of atmosphere.
  • Averted in Rocketship X-M, ironically enough given the movies' massive Hollywood Science. Scenes on Mars were filmed in California's Death Valley, which NASA latter used to test equipment due to be used on Mars because of its similarity. However aircraft pressure suits and breathing masks are all that's needed to walk around in, rather than the full spacesuits.
  • Star Trek:
    • It takes Chekhov a long time to find a completely lifeless planet to test a Terraforming device in Star Trek II: The Wrath of Khan. Implying that there's life almost everywhere.
    • Star Trek (2009) has Delta Vega, close enough to Vulcan that it can be seen in Delta Vega's sky but the only inhabitants are two non-Vulcan personnel in a Starfleet base. You'd think the Vulcan's would have colonized this planet before developing the warp drive.
    • In Star Trek Into Darkness McCoy and Carol Marcus beam down to a planetoid to safely open a missile. In the novelization McCoy notes that the planetoid must have an extremely dense core to have air and gravity.
  • Star Wars. Most notably, every world visited in the films has Earth-like gravity, regardless of size or composition.
    • The Empire Strikes Back:
      • It's not most definitely not a normal planet, but while the belly of the gigantic space slug lacks a breathable atmosphere, it apparently has normal gravity and pressure. Odd, as it's inside an asteroid in deep space. Han, Chewie, and Leia can walk around with only oxygen masks. Maybe the Millennium Falcon was able to extend its artificial gravity field or the asteroid field as a whole had some kind of atmosphere.
      • Bespin apparently has a breathable oxygen-nitrogen atmosphere despite being a gas giant. This is probably actually more realistic than the space slug incident; it's theoretically possible that a thin layer of breathable atmosphere could exist in the upper atmosphere of a gas planet and if it's Saturn-sized or smaller then the effective gravity in its upper atmosphere could be Earth-like. That'd be an incredibly convenient coincidence, but, well, the galaxy is a big place.
    • A few planets, such the desert world of Tatooine, the oceanic Kamino, and the fungus-covered Felucia, posses distinct environments, but nonetheless all have human-comfortable gravity and pressure and human-breathable atmospheres.
    • Mustafar is the only notable aversion in the movies. It's a volcanic planet with an atmosphere choked in ash. The Separatist facility seen has a forcefield keeping the air breathable, and everyone seen outside of it is either a Mustafarian, a Force user, or wearing a helmet or breathing mask.
    • Coruscant, despite being far closer to the center of its galaxy than Earth is to the center of the Milky Way and having three moons, is nonetheless identical to Earth in atmosphere, mass, diameter, rotational period, and orbital period. Maybe it even has the same continents as Earth, if you can actually find them underneath the enormous cityscape that literally covers the entire planet.
    • The prequels and EU offer some subversions, such as worlds whose native species that evolved to breathe ammonia or methane instead of oxygen.
    • Not mentioned in the films, but mentioned in the EU, Kashyyyk and the forest moon of Endor are said to have quite a bit lower gravity than standard. Hence, the incredible size of some of the flora and fauna. This is also why the Ewoks' primitive gliders are capable of flying, whereas on Earth they would never generate enough lift.

  • Andrew Doran: Callisto almost certainly doesn't have a race of sentient insects ready to invade Earth but it fits perfectly with the book's pulpy roots.
  • Animorphs: Mostly averted, with similarities generally being more by analogy, such as Andalite vs. Earth grass despite theirs coming in shades such as red. The Yeerk planet is completely different and unpleasant. Fittingly.
    • The Ellimist Chronicles features the interesting case of the Ketrans. Their home planet features giant floating crystals (upon which the Ketrans live) above acid oceans and an atmosphere that seems to consist mainly of hydrogen. When their home planet is invaded they flee in a newly built spacecraft to search for a new home, assuming that All Planets Are Ket Like. But, as anyone familiar with the Animorphs verse knows, the truth is that All Planets Are Earth-Like, and thus inhospitable to Ketrans.
  • Played with in the Antares series: most star systems resemble Sol, with a single habitable planet. There are no named uninhabitable solid planets. However, it is implied that just like Sol, there are a number of uninhabitable solid planets in most systems — New Providence, for instance, is identified as the seventh planet in the Napier system. Presumably, the other planets are simply unimportant.
  • Played with in the book Anywhere But Here. The heroes, a married couple, take off for space, going to planets that are already colonized and have people and aliens living on them. However, once the navigation system on their camper truck (yes, a converted camper truck) goes haywire, they quickly end up on a series of planets that aren't on the map. There's one very short stop at a planet filled with some kind of unbreathable (for humans) gas. They get stranded for a few days on a planet with breathable air, but everything melts like plastic when exposed to fire, including some of the rocks, and is inedible. The local water isn't good for them either.
  • In Arrivals from the Dark, the Orion Arm of the galaxy is divided between several galactic races, some of which have been in space for millennia, while one is known to have been star-faring for tens of thousands of years. Despite this, no race has more than a few hundred colonies. This is because habitable planets are few and far between. The Haptors have been in space for over three millennia and have about two hundred worlds. But their territory also includes thousands of systems they don't bother settling because they have no habitable planets. Humans have gotten good at terraforming barely habitable planets (after practicing on Mars), but it seems that only the Solar System has space habitats and domed cities on airless planets and moons (and only because many of those were built before humans got interstellar travel).
  • Earthlike planets in J.S.Morin's Black Ocean series take this to an extreme. Not only is the atmosphere breathable, not only is the food edible, but the very geography of the planet looks like Earth. Every earthlike does, however, feature a different dominant intelligent race based on the evolution of a specific kind of animal. Justified in that the entire galaxy was set up as an experiment by beings from another level of reality.
  • Isaac Asimov:
    • In The Early Asimov: Dr Asimov discusses the way he was influenced by the other pulp magazines to include several earthlike worlds when he was writing "The Callistan Menace". He claims to have known that it was improbable to the extreme even then.
    • In "C-Chute", humans are at war with the chlorine-breathing Kloros, not over living space (neither can live on the other's planets) but over control of resource-rich asteroid belts. One character points out the cynicism of dressing this up with rhetoric about "planetary honor".
  • Averted in Childhood's End by Arthur C. Clarke. The Overlords come from a world whose gravity is weaker than Earth's. Also, before the Overlords show themselves to humanity, one human character points out that as far as any human knows, the Overlords might breathe chlorine.
  • Used with twists in The Citizen Series: uninhabitable planets are simply ignored by the characters due to the nature of Faster-Than-Light Travel involving transiting into and out of the Continuum directly onto planet surfaces (or into the atmosphere). Even then there's variety: Nengue is volcanic and only marginally habitable, settled only to support a trading post between the Cutter Stream and the Riders. Mudball is geologically inert and has nothing but single-celled life (fortunately, most of it is photosynthetic algae so the atmosphere is breatheable). Allenson also once endures miserable conditions besieged during a monsoon season on a perfectly Earthlike planet.
  • Subverted by many works by Hal Clement, who would go to great lengths to invent non-terrestrial planets and populate them with believable life forms.
  • Subverted in the CoDominium universe.
    • Life-bearing worlds are common, but they aren't always fully compatible with Earth life. Nonetheless, most have at least a few areas where very hardy humans can survive, albeit with high mortality rates (the poles of Fyrstaat and Tanith, the equator of Haven). A rare few, like Sparta, are nearly ideal for Earthlife, if slightly off in gravity and length of day. And some worlds, like New Caledonia, require extensive terraforming. The alien-inhabited Mote Prime requires respirators. The double-planet system of Franklin/New Washington required Earth plants to be genetically altered for the red sunlight.
    • "Haven", the setting of War World, is a case of Pournelle getting together with Niven and asking, "Exactly how horrible can we make a planet while still letting humans breathe the air?"
  • Averted in Peter F. Hamilton's Commonwealth Saga:
    • Wormhole technology allows the ever present CST to use its exploration wormholes to scout new solar systems for "H-congruous" planets capable of supporting human life. The Commonwealth spans a vast amount of space, and most intervening systems between H-congruous planets are untouched completely by humans.
    • This is demonstrated in the first book, Pandora's Star, where an exploration team finds a planet that appears to be H-congruous, but the planet is rejected when the discovery is made that every single plant on the planet shoots or secretes acid. Suspicions are raised when the survey team notices none of the animal life will stand still for any significant length of time on the local grass equivalent.
    • Hamilton's other big book series, The Night's Dawn Trilogy, averts this trope as well, with habitable planets being classed as "Terracompatible".
  • In Brandon Sanderson’s The Cosmere, every planet we've seen can support human life. While most of these planets have god-like Shards who either explicitly or implicitly terraformed the planet, there are also worlds without Shards that are still very close to Earth normal. Per Word of God, Scadrial is a direct parallel to Earth, with identical time, environment, gravity, ecology (not counting when it was the World of Ash), and even culture. On the other hand, The Stormlight Archive's Roshar is only able to support human life in the most liberal sense of the word. Years are five hundred days long (but the days are shorter so the year only ends up ten percent longer than Earth normal), gravity is seventy percent of normal, oxygen content in the atmosphere is a bit higher, most of the animals are some variety of arthropod, the plants look like things you'd find underwater, and world-breaking highstorms blow from east to west every few days.
  • In the Darkover series, the titular planet itself and the hundreds of planets making up the Terran Empire.
  • Also subverted by Robert Forward in his novel Dragon's Egg. The planet in question is a ball of neutronium, the aliens are amoebas, and you STILL empathize with them.
  • In the Dune universe there presumably are plenty of non-Earthlike worlds, but they're not mentioned because nobody lives there. The least Earthlike world is Dune/Arrakis itself, and people only live there because it's the only place Spice is found. Salusa Secundus is apparently a fairly close second, and it's used as a prison planet and training/recruiting ground for the Emperor's Sardaukar shock troops.
  • Averted in The Expanse: You have all the planets in the solar system, of which only Earth is Earthlike. Once humanity gains access to the gate network they find lots of planets with life, none of which are 100% Earthlike. Ilus, the first planet we get a close-up of outside the solar system, has a breathable atmosphere but it's higher gravity, the local wildlife is inedible, and at least one lifeform has a fatal contact toxin by sheer coincidence.
  • Fallen Dragon, by Peter F. Hamilton, averts this trope as well. There's no planet completely suited for human life. For all of them, extensive terraforming is required before sending in the colonists. Amethi was a frozen world with very little atmosphere when the first settlers came, and a scene depicts the startled reactions of a bunch of children who see a cloud for the first time. On Thallspring the soil bacteria and other biota make it necessary for the MegaCorp running the colonization efforts to clear out all life in large swaths of land via periodic orbital gamma laser "soaks", in preparation for colony expansion. The process is stated to kill all bacteria down to a few meters underground. Santa Chico has a very high oxygen content, and its biosphere is a biochemical and medical goldmine, which is why the colonists modified themselves to adapt and eventually began using Organic Technology, only to revert to an agrarian society of bizarre xenophobic Furries once they grew bored with the Mega Corps periodically plundering their planet.
  • In Jack Chalker's "Four Lords of the Diamond" novels humanity discovers a solar system with four Earthlike planets — completely unheard of. It's only at the end of the series that they discover that the four planets were artificially constructed by an alien race as nurseries for their young.
  • While it seems to be the case in The History of the Galaxy with several hundred human colonies in known space, that number is only a tiny fraction of the total number of colony ships sent out during the Exodus. According to the author's website, that number is 7023. This means that the vast majority of those ships never found a habitable planet to settle. In fact, humanity's very first extrasolar colony ship Alpha ended up in a system with a barely habitable planet and had to implant colonists with metabolism adjusters that drastically reduced their lifespans, just so they could survive on the surface. One planet is known for being entirely covered in ice. The colonists there had to build marvelous subglacial cities that are now largely empty once contact with other, nicer colonies was reestablished. One novel mentions that anyone, who finds an unsettled habitable world, can expect to retire incredibly wealthy on the finder's fee alone. In recent years, corporations are starting to settle new worlds with machines in order to build up colonies and prepare planets for settlers (i.e. terraform them).
  • Honor Harrington:
    • Played more or less straight, but there are subversions and at least one deconstruction. The Manticore system is extremely unusual for having three Earthlike planets (partly a result of the very large habitable zone created by its Binary Suns), and part of the Star Kingdom's backstory is that Manticore was so Earthlike that a native disease crossed the species barrier and killed the majority of the first wave of colonists. The creation of a constitutional monarchy and noble class was a solution for the survivors wanting to maintain political power over the replacements the colony recruited from offworld. Meanwhile Grayson looked Earthlike from a distance but turned out to have horrifically high concentrations of heavy metals. And San Martin's gravity is so high that people can't live at sea level because the atmosphere becomes dense enough to kill an unprotected human.
    • Done to extremes with the very Texas-like planet of Montana that just happens to have a lot of animals that are almost exactly like real Texas animals. And everyone is a stereotypical ornery cowboy. It was handwaved by describing it as a planet colonized by very Texan-like people determined to preserve stereotypical ornery cowboy lifestyle.
  • Averted in The Interdependency series. In the 1500 years humanity has explored the galaxy (although, to be fair, the number of systems is actually only 47 due to Hyperspace Lanes), only one Earth-like planet has been found. Every other world is either a barren rock or a gas giant. Oh, and the link to Earth itself was lost over a millennium ago. Thus, most of humanity lives aboard space stations or in domed cities, with only a few million living on End, the habitable world. In fact, most people are so used to living in controlled environments that they view End as a shithole, partly because it's so far away from Hub, the center of the Interdependency. With the looming collapse of the Hyperspace Lanes, End is liable to be the only human colony to survive because it doesn't need machines to support the population. Later on, though, it's revealed that habitable worlds are more common in other parts of the galaxy settled by humans, particularly in the Earth Empire and the Assembly.
  • Forthorthe in INVADERS of the ROKUJYOUMA!? is largely identical to Earth. Humans can eat its food, drink its water and breathe its air without a problem (and Forthortheans can do the same on Earth). When Koutarou is suddenly transported there, he initially doesn't realise that he's on an alien planet. Forthorthe does have fantasy creatures like dragons, though.
  • Played straight in the Russian children's story "Journey to the Morning Star". Given that the story was written in 1960 and meant for kids, this is expected. The Lado system in the Coma Berenices constellation has three planets, all of which are (or were) Earth-like. The first planet, Aeo Tau (the titular "Morning Star"), is a virgin world full of prehistoric creatures such as dinosaurs. The second planet, Sino Tau ("Thunder Star") is a lush paradise with an advanced race of Human Aliens who are constantly at war with one another. The third planet, Etheri Tau ("Cold Star") is the oldest of the three and is no longer capable of supporting life, although it was once much like Aeo Tau. The Etherians are Human Aliens who have lived underground for thousands of years but must now relocate to Aeo Tau to survive. The warlike Sinots invoke The Right of a Superior Species and threaten any Etherian who sets foot on Aeo Tau with death.
  • Averted for the most part in Junction Point. Humans can survive on Mulolowa for extended periods of time, but it's far colder than Earth, with a thinner atmosphere. Ktrit, by contrast, is a tidally locked nightmare of a planet where the gravity is five times stronger, the weather far more violent, and water boils at the equator when it's noon.
  • In Larry Niven's Known Space universe, there are many planets that are liveable, but not Earthlike. Most of these were seeded with microbes as food sources by the Slaver empire, which died out billions of years ago, explaining why so many of them are biochemically cross-compatible; humans and Kzin, for example, can eat each other. Non-Earthlike worlds, such as high-gravity Jinx with its vacuum-exposed tidal "poles", and Plateau with its single livable mountaintop sticking up out of a high-pressure toxic atmosphere, were settled by humans whose early interstellar probes were rather poorly programmed regarding what kinds of places to green-light for colonization.
    • Specifically: the probes were programmed to radio back "come on in, the water's fine" if their sensors detected Earthlike conditions anywhere on the planet. Fair enough, you'd hate to reject a whole world just because a few places are a bit too hot or too cold; Earth is too hot or too cold in a few places. But the total area on Plateau where humans can live is only about the size of California, and We Made It was settled because the probe checked during one of the seasons it doesn't have constant three hundred mile per hour winds.
  • Played straight in H. Beam Piper's Little Fuzzy series, with the extremely Earth-like planet Zarathustra. Subverted in his work Uller Uprising, with the planets Uller (Breathable air and tolerable gravity, but silicon-based native life) and Nifflheim (hideously poisonous mining planet).
  • Lorien Legacies, despite playing a lot of sci-fi tropes straight, averts this. There are only eighteen life-bearing planets in the entire universe, hence why the Mogadorians are trying to conquer Earth after wrecking their own planet.
  • Played with in Mark Delewen and the Space Pirates; although the planets visited are Earthlike, the main character can't believe they are and worries about whether he can breathe the air.
  • Present, after a fashion, in much of Murray Leinster's work. In one of the Med Ship stories, the author notes that though non-Terrestrial ecologies are rarely strongly similar to Earth, they tend to be broadly similar, with grass-like plants, tree-like plants, pollinating flying creatures, prey species, predator species, scavengers of various sorts, etc. Most non-Terrestial ecosystems are somewhat compatible with Earth life, which can keep the Med Service very busy.
  • Mission of Gravity: Subverted. Mesklin is not only extremely cold, but its day is less than 20 minutes, so it's lens-shaped rather than spherical. The equator is only barely reasonable for humans to visit with assistance.
  • Confirmed and subverted in the Perry Rhodan series. The Milky Way –- rather the whole universe –- is full of Earth-like planets, often to be settled by Terran or related colonists. But it's also full of hot and heavy planets suitable for hydrogen-breathers, though oxygens-breathers and hydrogen-breathers rarely interact in day-to-day life. Also, many of of the earth-like planets have extreme environments, requiring genetic modification from the settlers. Though there are hundreds of heavy-gravity worlds with extreme climates that are being settled „naturally“ by one offshoot of humanity, whose ancestors got mofidicated once.
  • Averted in Alastair Reynolds's Revelation Space universe. Most planets are barely habitable and human inhabitants require bases with constant life support to survive. The only planets with breathable atmospheres tend to be the Juggler waterworlds, which have oxygen atmospheres. By far the only really Earth-like planet is Sky's Edge, which has a breathable atmosphere and didn't even require much terraforming, but it's native life is inedible to humans, there are no analogues of vertebrate animals, a lot of the fauna is pretty nasty and dangerous and even the history of the planet's colonization is far from idyllic. Also, Resurgam was once a very earthlike planet — until the local civilization of avian humanoids got wiped out during a mysterious cataclysm.
  • Averted in Riesel Tales: Two Hunters. Most of the mentioned planets are quite unique as opposed to being Earth-like, and the supplementary material indicates that such worlds are exceptionally rare. The eponymous Riesel itself is not much like Earth, with its never-ending cityscape and pale, polluted skies.
  • Averted in James White's Sector General novels, about a deep-space interspecies hospital. There are codes for different kinds of species, and some parts of the hospital have atmospheres that aren't breathable by humans.
    • Played with in The Escape Orbit by the same author. The protagonists are human prisoners in an interstellar war. The aliens who captured their ship drop them off on an "Earth like" planet, but what the aliens consider sufficiently Earth like requires the humans to adapt to the different atmosphere and to be pretty desperate to try eating what passes for local food sources.
  • Averted hard by E.E. Smith's Lensman and Skylark series. Intelligent life is found on all sorts of worlds, from red dwarf stars to environments at temperatures as low as one degree above absolute zero.
  • Slingshot subverts this in that yes, most planets that people visit are earthlike, because why else would go there? Still, quite a few non-habitable planets like gas giants are mentioned, and the habitable planets tend to have different climates all over them. And then there are places like Itaipú, where it rains acid, but hey, the ground is so rich in copper that it's worth the hassle. At least for The Company, after all, who cares for the miners?
  • Cleanly avoided in the Star Carrier series. There are Earthlike planets out there, as indicated by the Sh'daar numerical designation for humanity including our preferred atmosphere and the fact that the Agletsch don't seem to have a problem with it, but they are few and far between. Only two human-settled alien worlds allow the colonists to survive unprotected: Osiris and Vulcan (which happens to be located exactly where Star Trek's Vulcan is supposed to be), and of the two, only Vulcan has edible native life (Osiris has Mirror Chemistry). Unfortunately, one of the hostile races humanity later encounters has evolved on an Earth-like world (even though they look like large balls with dozens of mouths) and is capable of digesting terrestrial life forms... including humans.
  • Older Than Feudalism: This showed up in the world's first space-travel story, True History by Lucian Of Samosata, an ancient Roman writing in Greek. As it was written before modern astronomy, the Moon was earth-like, albeit filled with all sorts of wacky monsters, but then it gets really weird when it turns out there is also a civilization (and people, and trees) on the Sun.
  • Robert A. Heinlein's Tunnel in the Sky plays with this:
    • Averted, in that not all planets are Earth-like. Rod watches a diplomatic envoy from a race of chlorine breathers arrive on Earth before taking the test.
    • Discussed between Matson and Rod. Any planet hosting the survival test would be Earth-like to ensure a challenge that can beaten. Students would be formally warned of a hazardous environment beforehand.
    • Taken to an absurd extreme by a delirious Rod. The planet is so Earth-like — not just its physical environment, but its animals, plants, etc — he becomes convinced he's actually on Earth, learning otherwise only when the clouds clear up and Jackie points out the stars are different.
  • Initially avoided in Madeleine L'Engle's A Wrinkle in Time, where the characters visit in quick succession a two-dimensional planet and a planet where the air has a slightly different oxygenation level; later planets are sufficiently Earthlike for no problems to occur (and Camazotz even has Earthlike trees).

    Live-Action TV 
  • Averted by Babylon 5: the titular station has segments that rotate at different rates to simulate the gravities of various resident alien races, and entire sections dedicated to non-oxygen-breathers. There are even special toilet facilities for methane breathers! B5 was one of the first science fiction series on television to not immediately assume that aliens were capable of breathing oxygen and speaking English. On the other hand, there are some species, such as the Soul Hunters, who can process both nitrogen-oxygen and alien atmospheres.
  • Battlestar Galactica (2003) and its spin-off series Caprica zig-zag this trope. As depicted in the two series and the semi-canon poster map the Twelve Colonies themselves are all Earth-like to varying degrees; habitability ranges from pleasant worlds like Caprica and Leonis to more inhospitable ones like Aquaria (a planet-sized Antarctica) and Libran (overwhelmingly hot jungle). There are also references to moons and planets from the First Cylon War that apparently have snakes and other creepy-crawlies, so they are presumably Earth-like as well. Outside of the Twelve Colonies, however, the galaxy is a much more barren place. Throughout a journey covering thousands of light years, the Fleet encounters only five other Earth-like worlds of varying habitability: Kobol (original homeworld of the Twelve Tribes), New Caprica, the Algae Planet, Earth (home of the Thirteenth Tribe) and the second Earth, which is settled in the finale.
  • Played straight as you'd expect with the No Budget British sci-fi series Blake's 7. Though in fairness most planets they land on are or were human colonies, which would have been chosen for their ability to support human life. Spacesuits are only used for vacuum however, with the occasional mention of breathing masks. Thermal suits are worn for the more colder planets. There's a nice subversion of the trope in "The Harvest of Kairos". Servalan has captured our heroes and agrees that, if they hand over command authorisation of the Liberator to her, she will teleport them down to a planet with Earth-like conditions. Unfortunately the nearest such planet is Kairos, which happens to be a Death World thanks to its lifeforms.
  • Aversion: In Dans Une Galaxie Près De Chez Vous, where a dysfunctional crew of French-Canadians tries to find one of these, it turns out there's everything besides Earth-like planets!
  • Doctor Who:
    • Nearly every alien planet ever featured on the show has Earth-normal gravity and atmosphere.
    • The First Doctor serial "The Web Planet" has the distinction of being set fully in an alien galaxy, with (aside from the Doctor and his companions) a full insectoid supporting cast and environment. The Earthlings (and Gallifreyans) did not wear space suits, but at times did suffer from weakness owing to the difference in atmospheric composition.
    • It was parodied in the First Doctor serial "The Daleks' Master Plan", when the Doctor was nervous about the effect of poisonous gases in the atmosphere of a city on his companions. It turned out to be an industrial city Oop North, and the gases were just then-normal levels of air pollution.
    • In the Second Doctor serial "The Moonbase", the characters wore special atmosphere suits to explore the Earth's Moon. They were never seen again. The show's writers most likely did it because it was set somewhere that the viewing audience already knew didn't have a breathable atmosphere.
    • Space suits showed up again much, much later, in the Tenth Doctor story "The Impossible Planet"/"The Satan Pit". He didn't make them on his own though, but borrowed them.
    • In the Tenth Doctor episode "Midnight", the title planet is totally unlivable (except it turns out it isn't, but that's beside the point); it's apparently one big lump of crystal with no atmosphere and a star that emits very deadly rays. But Professor Hobbes goes on about this like it's remarkable for a star system NOT to support life.
    • The Doctor's spacesuit makes a return in "The Waters of Mars", set guess where.
    • The Eleventh Doctor is seen using the same suit again in "Hide", though equipped with a brand new helmet design this time around. He wears it on Earth, at the beginning and end of its existence.
    • The Twelfth Doctor breaks out the spacesuits again in "Kill the Moon", for obvious reasons.
    • In Series 10, the Twelfth Doctor and company go to Mars, so naturally they wear spacesuits — a new design this time.
  • All the inhabited worlds in Firefly were deliberately terraformed, though they each have their little quirks. The core planets, which have been extensively terraformed, are comfortably temperate in climate. The rim planets, where all the poor people live, tend to be a bit more on the arid side (which helps with the general Space Western aesthetic of the show).
  • Sliders, which dealt with Earths in parallel universes, mentioned once or twice that the nature of the wormhole would keep it from dropping the heroes in universes that were patently incompatible with human life. Or inside rocks. Although it did once briefly drop them on an Earth that was covered completely with fire. Of course, they were standing in the one safe spot, and the fire was alive and followed them.
  • Space: Above and Beyond uses Earthlike planets in some episodes (the war with the Chigs starts when they destroy a pair of Earth colonies on extrasolar Earthlike planets), but the majority of planets visited don't have atmospheres breathable by humans and the Chigs require a different mix of gases altogether. Then the Grand Finale reveals this to be false. The Chigs can actually breathe the same air as humans, they've just gone out of their way to keep their real appearance hidden... for reasons. They actually claim that they come from the same primordial DNA as all life on Earth, having been spread to their homeworld by Panspermia.
  • Stargate:
    • Stargate SG-1: Used liberally and frequently made fun of.
      • Most of the planets in the series are fairly Earth-like, though there are some exceptions where the team has to wear special space suits to explore them. This is explained as the Goa'uld (and before them, the Ancients) having terraformed the planets millennia in the past. And once again, Stargates are placed by once-humanlike Precursors who would have no reason to put one on a world that would kill you the second you exited. Some of them were once Earth-like, but have since suffered some sort of disaster that has rendered it uninhabitable.
      • And then, there are those examples where Planets are absurdly present-day Earth-like to the point where Ikea furniture would fit right in. Particularly common in later seasons and Stargate Atlantis.
      • Lampshaded in "Prodigy", when Carter's arrogant young cadet emerges from the Stargate and says, "So this is another planet? ... Doesn't look that different from home."
      • They actually played with/subverted this trope in the teaser for a Season 9 episode. Most of the alien worlds, as stated, look almost exactly like the woods around Vancouver so the audience wouldn't be too surprised to have an episode open with a Jaffa running through one of these alien forests... until he gets hit by a truck and you find out that he was on Earth All Along.
      • O'Neill takes a swipe at this (and at California Doubling) at one point. "Why do they always look like Canada?"
      • In "Heroes, Part 1", SG-13 is doing a standard recon mission, and the team leader Col. Dixon takes bets on what they're going to find on the planet. One of his mauve shirts pipes up with "trees". Dixon says he's "disqualified for being a smart-ass."
      • Double Subverted in Season 1's "Solitude" when Sam and Jack are trapped in an ice cave. Sam gets a look at the surface outside and declares it's an ice planet and there's no way out. In actual fact, they're on Earth, in Antarctica, which was a temperate zone when the Beta Gate was built there millions of years ago.
    • Stargate Universe averts this and Human Aliens by having most worlds visited barren and lifeless and mostly only good for picking up the one or two useful natural resources before moving on. And SGU is a good example of why this trope falls under Acceptable Breaks from Reality: barren rocks really aren't that interesting of a setting. However, sometimes the ship stops at a planet automatically, and the team will explore others that happen to be in range. The ship rarely stops at nasty ones, but with these others, you're rolling the dice. And as always, the then-humanlike builders of the gates and the ship have no reason to put gates on useless or deadly worlds.
  • Star Trek:
    • Star Trek: The Next Generation may have had the ultimate subversion: Earth, 3.5 billion years ago, just prior to the first protein being formed by two amino acids. Presumably, if not for Q's abilities, Jean Luc Picard couldn't have breathed on that surface.
    • Of course, the First Humanoids spread DNA to most life-bearing worlds to ensure parallel Hollywood Evolution. Many alien planets have been described as having the equivalent of orchids, vultures, cats, and other terrestrial-specific animals as well as Human Aliens and Rubber-Forehead Aliens. The Klingons even have coffee.
    • Averted in Star Trek: The Original Series. The planet Elba II had a poisonous atmosphere that would kill humans breathing it before very long, "The Way to Eden" had a planet that was technically habitable (right sunlight and air quality), but all the flora excreted a deadly acid, and the fruit was lethal.
      • The TOS Writer's Guide acknowledged this trope right from the start: the formal orders to the captain of the Enterprise found therein contained instructions that the ship would mostly confine its operations to Class-M planets, though the ship did, of course, carry spacesuits.
    • Averted in Star Trek: Voyager episode "Demon". A class-Y planet is colloquially known as a 'Demon' class planet because it's as harsh as the class-N Venus. Another class-Y planet was chosen as a homeworld by a group of rogue holograms specifically because of the harsh conditions; it didn't pose a problem to them, but it would protect them from anyone else who might give them trouble.
    • The fact that the recurring Benzite species in The Next Generation and Deep Space 9 are one of the few species shown that can't breathe normal air without a special device implies that their homeworld, Benzar, is not Earthlike.
    • But there are also episodes where the reason for the crew to look closer is that the planet, or an area on it, is Earth-like when it shouldn't be (Sufficiently Advanced Aliens did it).
    • And frequently enough in all Star Treks, "only" one or two planets in a system will be "Class M" (that is, Earthlike) and no one ever beams down or lands on a planet without checking first. Sometimes the checking is offscreen, but if the away team know how to dress, they probably also know the air won't kill them them the second they arrive.
    • Then, there are the in-betweeners (planets that are nearly Earthlike and can support the away team with the busted shuttlecraft but only for a short time is a common setting). So all planets in Trek aren't Earthlike — but there are certainly a lot of them, and close to Earth, and it is a striking coincidence that the planet a shuttlecraft crashes on almost always happens to be something that can support the away team long enough for them to be overdue getting back and the others to go find them.
    • In one episode of Enterprise, Tucker crash lands on a small moon that is habitable while it is night time. Once the moon rotates to face the sun, it is uninhabitable for human life, as it is too hot.
    • The Tholians (seen in TOS and Enterprise, and referenced in the other series) were hermaphroditic, insect-like humanoids who lived in an environment of around 480 Kelvin. Presumably their homeworld was very much unlike Earth.
    • Zigzagged with the Breen. The thermal suits they wear constantly seemed to suggest their homeworld was a frozen wasteland, but according to Weyoun the world of Breen is actually quite temperate (and presumably Earthlike).
    • Bajor is very much Earth-like, which fortunately means that the environmental settings on Deep Space 9 work for both humans and Bajorans.
    • Played with for Cardassians. They can breathe the same air as humans, but in the DS9 pilot Sisko complains about the Cardassian environment settings on the station being uncomfortably warm and in the episode "The Wire" Garak reveals that the reset human / Bajorian environment on the station is both too cold and too bright for him. So Cardassian Prime is similar to Earth, but not exactly the same.
    • The Star Trek: Voyager episode "Displaced" introduces the Nyrian. Like the Cardassians, the standard settings on a human ship are too bright and cold for them. They turn out to be hostile, and trap different species in prisons with environments specific to them. One of which is a frozen wasteland, presumably that species' planet is not Earth-like. Another species is indicated to come from a desert like planet (he comments that their prison is a lot "greener" than his).

    Tabletop Games 
  • In BattleTech, 'Earthlike' is variable. No planet is exactly like Earth in terms of comfort for humans, which is commented on by those who are lucky enough actually travel there. Most of the settled worlds are fairly close, though there are wild exceptions, like the domed cities of Sirius V (the atmosphere is poisonous), or Tharkad, the Lyran capital, which is in a serious Ice Age (though contrary to persistent fan rumor, it is not completely frozen and does have an equatorial tropical band, something the writers take pains in pointing out on multiple occasions). Justified in that Humans would naturally pick the Earth-like planets to settle first.
    • The Star League in its heyday did in fact do rather a lot of terraforming and other mega-engineering projects. Then the Succession Wars started and military budgets took priority over such expensive flights of fancy and massive terraforming projects stopped.
  • GURPS Space arguably goes too far in the other direction. Enough that the fourth edition had you deciding whether you wanted an Earthlike planet to start with and then designing the physical characteristics with that in mind. The main alternatives being gas giant, rocky moon/asteroid, ice moon, or toxic terrestrial.
  • Space 1889 Mercury, Venus, Mars and the moon can all support human life quite easily (if not necessarily comfortably), although only Mars has any sort of civilization on it — Mercury has only very basic life, such as trilobites, Venus has sentient lizardmen, although they are only at stone age level. Mars has an ancient civilization based around their canals, although they have lost the technology necessary to build new canals or even to maintain their cities. The Moon can also support life, although there is no atmosphere on the surface — it only exists nearer to the Moon's core.
  • Justified in the Traveller RPG, where Earth life (including Transplanted Humans and Uplifted canines) were spread by the Ancients.
  • Warhammer 40,000 averts this trope pretty impressively. The Imperium of Man classifies planets into several different categories, some of which are Earthlike. Even within a category there is enough variation that most planets aren't a Single-Biome Planet. And being the kind of universe it is, most of the settled planets are not, in fact, habitable. The Imperium seems to absolutely love settling worlds that humans can't actually expect to survive on.

    Theme Parks 

  • Spherus Magna in BIONICLE. When The Shattering happened, it was divided into three SingleBiomePlanets — one jungle, one mostly desert, one ocean. Although it's fair to assume not all inhabitants survived the event, most species retained a breeding population, and were able to function on the new planets with no apparent alterations to the atmosphere or gravity. Furthermore, two of these "planets" are actually moons of the bigger planet, yet the inhabitants didn't seem to suffer from a 28-day long day-night cycle. Then when Spherus Magna was restored to its Earthlike state, there was no mention of increased gravity whatsoever.

    Video Games 
  • The Beta Caeli system in Alien Legacy has not one but two Earth-like planets, named after the Greek goddesses/Titanesses Rhea (mother of the gods) and Gaea (earth goddess). Gaea is the third planet like Earth but lacks a satellite. Despite this, it has plant and animal life, even though it would be difficult for them to evolve without tides. Rhea is the second planet like Venus but has the same conditions and even life forms as Gaea. The game implies the presence of a Moon-sized satellite prevented a Venus-like greenhouse effect. The rest of the planets are similar to Solar System planets. All planets (including satellites and asteroids) except for gas giants are colonizable. However, the late-game reveal that the two habitable planets were seeded by the H'riak may imply that this is not a natural occurance. The existence of the Centaurians also implies a habitable planet in the Alpha Centauri system, although whether it's habitable for humans is anyone's guess, as nothing is known about the Centaurians except that they're Absolute Xenophobes.
  • In Destiny:
    • Most of the planets you can visit in the solar system are relatively Earth-like (in that humans can walk around on them and breathe the atmosphere) but this was due to the Traveler going around and terraforming them.Venus, Mars, Io, and Titan, for example, are all inhabitable by humans, while Earth's Moon has at least some atmosphere. That said, each planet retains features from before its conversion. For example, Venus is still a yellow planet with a thick atmosphere and strange weather patterns, but now it can support vast jungles and human cities. Mars remains a red, sandy desert, but it's atmosphere is warm enough, thick enough, and breathable enough for humans. Io, despite being a tiny moon, was turned into a verdant green Earth-like world.
    • Mercury was intended to be a very Earth-like world by the Traveler, but the Vex came along and converted the entire planet into a vast Vex machine. And while 7066 Nessus looks Earth-like, only with red vegetation instead of green, the entire planet is another Vex machine world and it has an atmosphere intensely toxic to humans.
  • Subverted in Earth 2160. The game takes place on a number of celestial bodies in the Solar System and around the nearby stars (one mission takes place on a very large comet), but of these, only 2 planets are actually suited for human habitation. One of the is a desert planet reminiscent of the one in Stargate (complete with ancient alien pyramids), while the other is a very Earthlike planet called Eden. The main characters are visibly surprised when they see a video from the surface, and some even suspect that it's actually old Earth footage.
    • All of the above locations are made a bit less pleasant by the Morphidian presence.
  • While most human systems are inhabited in one way or another in Endless Sky, this trope is subverted, as most colonised planets are lacking in one way or another (high tectonic activity, frigid temperatures). Additionally, amongst the planets that are Earth-like, most have had to be Terraformed in one way or another.
  • While Endless Space probably has more Earth-like planets than would be possible in Real Life, there are also a lot more planets that are inhospitable, although colonization is possible after extensive research. Even terraforming may be possible closer to the end of that research branch, although gas giants and asteroid belts (which can also be colonized) can never be turned into hospitable planets.
  • The Escape Velocity games feature all kinds of planets, including gas giants. The most you'll ever see of one, though, is a little pre-rendered image. Many of the ones that you can actually interact with are habitable for one or another reason.
  • The Lunarian Moon (no, that's not redundant) in Final Fantasy IV has a perfectly breathable atmosphere and its gravity is identical to the heroes' homeworld. Just ignore the man-sized viruses and the killer plates of flan.
  • Freelancer has roughly a 50/50 ratio of Earth-like planets and somehow uninhabitable worlds. On one hand, you have planets such as Cambridge or Stuttgart, full of fertile farmlands, or Cura, a planet full of heavenly beaches; but on the other hand, you also have planets like Pittsburgh, a barren, deserted wasteland punctuated with mines, or California Minor, a little frozen ball under terraforming.
    • Most of these planets are covered in rocky pine forests.
  • Galactic Civilizations II, with all of its expansions in, finally adds toxic, ocean, high grav, barren and other world types. However, you can research technologies to colonise all of them.
    • Except possibly on the highest "usable worlds" setting, nearly all of the worlds you encounter are not only not earthlike but completely uninhabitable quality 0 gas giants or tiny balls of scorched or frozen rock. Although there are weird mega-events that occasionally roll through and turn an entire system into medium to high quality potential colonies, regardless of the size or nature of the planets.
  • Subverted in the Halo series. It's revealed in the expanded universe that it often takes decades of terraforming to make a colony world suitable for human use. There's also an outright aversion in the Grunt homeworld, which has a methane atmosphere. That said, there are plenty of planets that play this fairly straight too, even if they have an extra moon/sun or two.
  • In the Homeworld series, while Hiigara falls under this trope, Kharak is only partly habitable, being a harsh desert planet that only the poles are comfortably habitable, while maintaining .98g gravity and breathable atmosphere. Justified in the fact that since the original Hiigarans were exiled there, the planet must've been chosen specifically as being harsh, but not too inhospitable. Except the prequel Homeworld: Deserts of Kharak reveals that Kharak is getting less habitable every year, with the great desert pushing back on the habitable areas at the poles. This is why the Northern Coalition is investing heavily in space travel. It's either space or extinction for them. The Gaalsiens don't agree, though, citing an ancient prophecy about the god Sajuuk raining death from above for transgressions (they're actually right, in a way).
  • Mostly averted in Kerbal Space Program — since it's based on the real solar system, only the third planet from the sun, "Kerbin," is Earth-like. The rest of the planets and moons are lifeless, and many don't even have atmospheres. However, Laythe, one of the gas giant's moons, conveniently has oxygen (which can only exist in a planet's air for long periods if it's constantly replenished by plant life) so that jet engines will function.
  • Played with in The Mandate as the Osmani faction had the unfortunate luck of having their colony ship land are a very hazardous world. This forced them to become cyborgs in order to survive.
  • Mass Effect notably averts this; the vast majority of the planets encountered are actually very hostile to human (or most) lifeforms. This makes those inhabitable worlds that can be found all the more valuable.
    • "Vast majority" here meaning that only three planets shown in the first game are safe for humans, in a game that shows around a hundred. Most of the planets you visit require spacesuits and sealed environments for survival, and sometimes not even your Powered Armor/space suit will keep you alive for very long. The 80%+ of planets you don't visit are often even more inhospitable.
    • It's also noted on the info screens for several planets note that what makes them unsuitable for humans make them perfect for volus/hanar/elcor etc.
    • A few planets actually are more like subversions, too. Like Nodacrux, the planet with a much higher oxygen concentration than Earth's. It's enough for humans to feel plenty comfortable, like being in a hyperbaric chamber... but it makes thunderstorms absolutely devastating to anything they catch in their path, and vegetation goes up like tinder in amounts that make the California wildfires look like campfires. Not to mention huge insects and plants that give off pollen that causes death by allergy in seconds.
    • Even planets that humans actively colonize aren't all Earthlike. Eden Prime, which you visit at the beginning of the game, is pretty close to Earth, except for its sixty-four hour days.
    • From Mass Effect 2 onward, most of the planets you visit are at least partially Earthlike. Key word being visit: you only ever touch down on planets with some kind of habitation, even if it's just a tiny mercenary resupply point. Also, the Blood Pack have a base set up on a world that's filled with gas that's toxic to all your crew members but the Vorcha can live there fine. The reason there aren't nearly as many inhospitable worlds visited past the first game is because the open-world exploration was mostly removed.
    • Mass Effect: Andromeda is basically about the main character trying to find an actual Earth-like planet for galactic colonization, after all the scanned "Golden Worlds", supposedly Earth-like planets, turned out to be Death Worlds. Later on in the game, the earthlike-ness turns out to have been because a group of sufficiently advanced aliens went to a lot of trouble to make them nice and cozy for their own ends.
  • Averted in the Master of Orion series. Terran class planets exist, but so do Toxic, Desert, Ocean, Tundra etc. etc. Terraforming can help make them more habitable.
  • Meteos averts this trope. There is only one Earth-like planet in the game; every other planet is unique and un-Earth-like in its own ways. Some of these are not even planets at all. Intelligent life, in this series, have sprung up on dwarf planets, asteroid clusters, dimensional rifts, interstellar gas clouds, neutron stars, and even mythological realms.
  • Averted in No Man's Sky. Within the planets you can explore, many of the planets players will encounter will be lifeless rocks, only 10% of them will have life on them, and only 10% of those worlds will be flourishing, earthlike "garden"-type worlds. That doesn't necessarily mean that the non-earthlike worlds (or barely earthlike worlds) will be useless, though: a barren world may have more valuable resources in it than an earthlike world.
  • Averted in Odysseus Kosmos and His Robot Quest. There are only two planets of note in the Gargan-Hope binary system: Calcutta and Ithaca. Ithaca is an ice-covered lifeless rock, with the "ice" actually being composed of inert gases, not water. The surface temperature is only about 30 degrees above absolute zero. Calcutta is a super-Earth about 1.5 times the size of our planet. The average surface temperature is zero Celsius, and yet there's liquid water on the surface, which is probably the only reason the crew went down to investigate. Since Calcutta is close to Gargan, it experiences a lot of Time Dilation, to the point where minutes on the surface translate into years aboard the ship.
  • Averted in Outpost. No star has an Earth-like planet in that game, at least until you develop terraforming and the friendliest one are those that are Mars with the Serial Numbers Filed Off, with planets there being identical to Real Life Solar System bodies (including even two moons and two minor planets) in everything but surface features. The game's demo showed different planets, but it was one of the features missing on it (see entry for Outpost2 for more.)
  • In Rimworld, all the procedurally generated planets are suggested to have been terraformed and seeded with Earth lifeforms (though some are genetically modified) at some point long before your settlers crashland on them. Also, crashlanding on an airless rock would make for a really short and uninteresting game. The game averts Single-Biome Planet (though there are apparently plans to implement them in future builds) as there are a number of biomes to play in: a band of Temperate Forestnote  runs across the northern hemisphere, giving way to Arid Scrublandnote , Desertnote  and Tropical Junglenote  in the south, and Boreal Forestnote , Tundranote  and Ice Sheetnote  in the north.
  • Averted in Sid Meier's Alpha Centauri — Planet is called "earthlike" at the very beginning, yet some of the many problems you face in the course of colonizing Planet are the poisonous atmosphere (90% nitrogen rather than 78%, combining with higher gravity and a thicker atmosphere to give you nitrogen narcosis if you try to breathe it), inedible plantlife, and hostile (very, very hostile) native fauna. And the game doesn't hide the fact that even such "earthlike" planets are very rare.
  • Averted and played straight in SimEarth. Depending on the player actions, the planet could be just like Earth, or something else altogether. Life that evolves on the planet will be Earth-like, however.
  • Space Colony averts this with no planets capable of supporting life without assistance, the planet range from barren, to volcanic and a few that have a bit ''too' much life on them.
  • Comprehensively averted in Space Empires IV, in which you set your race's preferred atmosphere and planet type (ice, rock or gas giant) and start out only able to colonise those.
  • Space Quest III: The Pirates of Pestulon sort of averts this with the Planet Ortega, which while the atmosphere is breathable, the surface is too hot for humans who don't have special clothes.
  • In Spore, all the planets are rocky and have plant life (albeit some very bizarre ones) on them. Justified, as each planet is where your creature will live and evolve. This trope is utterly averted in the Wide-Open Sandbox Space Stage, where most planets are T0 inhospitable rocks, and the few life-bearing planets are mediocre T1. A nice naturally-occurring T3 planet is fantastically rare. If you want a nice planet, you'll need to Terraform it.
  • Star Control 2 averts this trope: it has at least 50 types of planets. The kinds that support (humanoid) life are rare; many — not all — races come from home planets of these types (and among them (water worlds as are known there) are included those with temperatures so high that their water is as water vapor as well as those so cold their water is frozen). Each type has common characteristics — likely minerals, ranges of size and strength of gravity, tectonics, and so on. All but gas giants can be landed on and explored via Lander vehicles.
  • For most part, StarCraft averts this, as the vast majority of planets in the Koprulu Sector are said to be largely inhospitable to human life. In the original game, only Aiur appears to be anything close to an Earth-like planet, with most other planets supporting permanent human habitation depicted as semi-arid wastelands. According to the backstory presented in the manual, the colony ships were originally sent to colonize a habitable planet that was one year away from Earth, but ended up traveling blindly through space for twenty eight years when their navigation systems shut down. The supercomputer controlling the ships forced them to land on the nearest habitable planets before life support systems failed.
    • Expanded universe materials and the sequel game expand the number of Earth-like planets, with Umoja, Agria, and Meinhoff being notable examples. Korhal IV also used to be a nice place to live, but most of the planet was flattened by nuclear missiles before the start of the first game.
  • Star Ocean: Till the End of Time is guilty. Although there are a variety of planets not suitable for humans to live on (or those where it'd be very difficult for them to thrive), the main party always conveniently lands on one where they can breathe the air and move around comfortably despite any effects of the gravitational fields.
  • Averted in Star Ruler where some planets have a charred appearance and are clearly not Earthlike.
  • Stars! (1995) averts the trope. Part of defining an alien race is specifying its ideal and habitable range for temperature, gravity, and radiation, which determines which planets your colonists can survive or thrive on.
  • In the old Star Trek game for the NES, players could technically only land on planets with breathable atmospheres, but all that it actually meant is that the designers only made planets with oxygenated atmospheres. The rest are just there as a backdrop.
  • Stellaris does have planets that aren't inhabitable, such as gas giants, "barren worlds" (including Mars, asteroids, most moons), and toxic worlds. And inhabitable planets themselves are divided into eleven types (Earth is "continental") and species favor the same type of planet they were native to, though populations can be genetically modified to favor different planet types and inhabitable planets can be terraformed into different types.
    • Of particular note are Gaia Worlds, which are somehow 100% inhabitable to everyone and are considered "holy" by Spiritualists, though implied to be produced by Precursor terraforming projects (or the player when they unlock the late-game tech). And Tomb Worlds, which are nuclear wastelands inhospitable to everyone not native to such planets.
  • Despite the indubitably Alien Sky, the planet Trace is set on. You can spend as much time outside as you want. The plants are also rather earth-like.
  • Invoked in Ultima Underworld II, when Iolo expresses concern that one of the facets of the gem might transport you to a planet of poisonous gas or an ocean floor.
  • Warcraft only has three explicitly known planets, Azeroth, Draenor, and Argus, all of which are or were very earth-like. Draenor was ripped apart by magical experiments and drained of its life by demonic influence, which makes it a very alien place... with the exception of Nagrand, which somehow remained untouched. What else is left of the planet still qualifies as earth-like as far as this trope is concerned. Life is still possible (even though half of the zones have no water or any plantlife other than herbs, but that's more an issue of Gameplay and Story Segregation). However, the alternate Draenor players visit in Warlords of Draenor is set in the past before all the aforementioned planetary corruption happened and looks perfectly normal for the most part. Argus was turned into a smoldering Death World by the Burning Legion before being made into their central base planet, but flashbacks in Legion show that it used to be just as earth-like as Azeroth and Draenor.
  • Averted in the X-Universe. There are a fair number of Earthlike planets (most of which are colonized by the Argon), but plenty are decidedly not Earthlike and still inhabited. The Boron homeworld Nishala is an ocean planet with an ammonia atmosphere, and the Terrans' Lost Colony Aldrin is an airless planetoid that presumably uses pressure domes or the equivalent. The Terrans also have settlements on several objects in the Sol System other than Earth. And that's before you get into the many planets that are absolute uninhabitable hellholes covered in lava flows or what-have-you.

  • Darths & Droids tries to explain this trope as applied to Star Wars. When unexpectedly asked about what Naboo is like, the Game Master automatically responds: "Um... Earth-like?", and the players notice that it's "convenient". Later, when they approach Tatooine, they ask the GM if it's "conveniently Earth-like again", and he hastily assures them that it's a planet-wide desert. Only, for the purposes of this trope, it's still Earth-like enough.
    • "So it's Mad Max World?"
    • Later subverted somewhat with Naboo, as well, as they figure out that, while it may have an Earth-like surface, its geology would have to be radically different from ours for some of the things they do in the game to be possible.
  • Earthsong justifies this one fairly well — all the aliens encountered are from Earthlike planets for the simple reason that planets must make themselves Earthlike before they are given the secret of supporting life.
  • This Irregular Webcomic! strip demonstrates what will happen if this trope didn't exist.
    Man, this is the hundredth tide-locked airless rockball orbiting an M-dwarf we've found in a row!
    You forgot that system with the uninhabitable gas giant with no interesting features whatsoever.
  • Ronin Galaxy: Just another average day in Japa— Whoa! Those are some huge potholes. That look suspiciously like Moon craters....
  • In the "GOFOTRON" arc of Sluggy Freelance, the cast visits the Punyverse, Another Dimension consisting of about one hundred planets, all but a few of them inhabited, and packed together within easy traveling distance. The strip actually addresses the oddness of this, with Riff saying, "I've never seen a universe so ... deliberate." Later justified when it's revealed that the Punyverse did not evolve naturally, but was actually created for an alien science project.

    Web Original 
  • Downplayed in Alien Biospheres. While Biblaridion does make Tira pretty Earth-like to make it easier to come up with organisms, he adds some unique twists such as lower gravity, extra hydrogen sulfide in the atmosphere, and a larger moon resulting in larger tides.
  • Land in the Stars: Every planet except for a few gas giants (moons included)is composed of earthlike planets with slightly divergent climates all centered around a primary star.
  • Nexus Gate: The worlds of Taivas and Cielo.
  • Many of the planets and moons in Orion's Arm are rather earthlike, but it justifies it in that most of them were terraformed in some way. However even if you include the terraformed planets they are still greatly outnumbered by the non earthlike planets in this universe, ultimately making this an aversion. The non earthlike planets in Orion's Arm can be anything from dead rock worlds, to planets covered in atmospheres of strange gasses and pressures, yet thriving with (non earthlike) life.
  • Justified in Planetcopia, since the entire project is a study in geo-ecology and geoclimatology.

    Western Animation 
  • In Futurama, the only non-Earthlike planets shown so far are a few moons and asteroids without atmospheres, and one high-gravity (but otherwise Earthlike) planet. Even the world with three giant suns, apart from being a bit warm at full noon, was perfectly livable to humans.
  • Phineas and Ferb is especially odd — even Mars is Earth-like enough for the human characters to survive, not to mention an asteroid that had air and normal Earthly gravity. Of course, the latter had a milkshake bar on it, so presumably the aliens terraformed it in some way. (It Makes Sense in Context. Sort of.)
  • Averted in Roughnecks: Starship Troopers Chronicles, on Pluto, Hydora, Tophet, Zephyr, and Klendathu the Roughnecks need to wear pressurized suits, the only planets with shirtsleeve environments are Earth and Tesca. And T'Phai, a Tophet native who joins the squad after that campaign, needs to wear his own pressure suit off his homeworld.
  • Averted in Star Trek: The Animated Series. Personal environmental force fields allow the crew to explore planets without atmospheres while wearing nothing but a uniform. (A yellow line around each character was easier to animate than spacesuits, which are what the live-action Treks use.)
  • In Stroker and Hoop the detectives encounter an elaborate con with a woman pretending to be an alien needing sapphires to return to her home planet "Sapphiria". Turns out she really is an alien and needs sapphires. At the end, one of the detectives crash lands on an alien planet, sees a jogging alien and immediately tries the same con, claiming to be from the planet "Goldia" and he needs gold. In a few seconds he says "Wait, this isn't oxygen" and collapses.
  • In the '90s X-Men: The Animated Series cartoon, a passing Shiar ship was bored that they had to map out a section of the universe filled with uninhabited worlds. This was the section that Dark Phoenix fried. Note, this is more of a case of softening her Face–Heel Turn, as in the original comics she did destroy inhabited worlds; and some people consider that unforgivable.