The story takes place on present-day Earth. Maybe give or take a few decades or centuries. However, the world is really young. It doesn't have billions of years behind it, nope, it has only been around for a few thousand years.
Note that in theory, that doesn't have to mean that the world is created. However, a young Earth usually come with some kind of creator in the form of a God, alien, time-travelling human or simply an author writing the story of our lives. If the creator is a computer programmer and our world is just a simulation rather than the real Earth, then see instead Inside a Computer System.
In either case, what about all the scientific evidence that the world is much, much older? What about ancient fossils and radiometric dating? What about starlight that has traveled at light-speed from distant galaxies for billions of years, and so on? There are several approaches to this:
- The They Just Didn't Care approach: The world is young, period. In this setting, science agrees or is not practiced, so no conflict.
- The Science Is Wrong approach: "Scientists believe the silliest things, lol. Evidence Schmevidence." A subtype of this is also found where the 'official' scientific explanations were created by an Ancient Conspiracy as a way of misleading the public about things which they'd prefer were kept secret.
- The Jerkass Gods approach: Yeah, the evidence is there. But God or Satan placed it there as a Mind Screw or a test.
- The Post Modern approach: The world is as old or young as people believe it to be, or simply a far stranger place than we can comprehend. The theory that the universe was created six minutes ago, assuming that we all spawned complete with memories and unwashed clothes and everything, is equally valid to any other theory: Who said that time has to be linear, one-dimensional, or begin with creation anyway! The Earth might just as well have been created with a past, or time has expanded backwards as well as forward.
- The Lampshade Hanging approach: God did put the ancient-looking dinosaur skeletons there and everything, but didn't mean anything by it. He was simply decorating His creation!
No real life examples, please; we don't care what people believe (or are claimed to believe) in real life, because it doesn't matter from a storytelling point of view. If you really want to see Real Life examples of this trope, consult young Earth creationism at That Other Wiki.
- In Legend of the Overfiend, the world is only three thousand years old. The intro of the movie version also scolds Mankind for being so ignorant and foolish that they don't even know about parallel universes, so one can expect that people are supposed to simply shut up about their silly little theories about the origins of the universe.
- Chick Tracts holds that Scientists are evil, and need to be cured of their heresy by the power of Easy Evangelism.
- In Preacher (Comic Book), The Bible is literal truth, and the reason we have reason to believe otherwise is that God is desperate to be loved: If our lives are Hell on Earth and we don't have any reason to believe that God even exists but we still love him anyway, then our love is such a sweet ego-boost in His eyes.
- Sandman goes for the postmodern approach: Time, history and reality are all very relative concepts, and what says that an act of creation can't be retroactive anyway? This is discussed in most albums, in one way or another.
- In A Dream of a Thousand Cats (a short story in the third book), the universe-as-we-know-it cannot possibly be older then a few years or decades - but the apocalypse wrote the old universe out of history, and created the new universe retroactively.
- The first albums of Lucifer averts this trope, however. In spite of Lucifer being a spin-off from Sandman. This version of the setting make it unambiguous that biblical events took place billions of years ago. Later albums kinda throw the concept of linear/objective time out of the window, returning us to square one.
- The Fables album The Great Fables Crossover takes the postmodernist approach: The world is the story we live in - it's recently written, and in danger of getting unwritten.
- Discussed in the Druuna / Morbus Gravis series. However, while it turns out to be true that Earth is young, it also turn out that It's not really Earth! In the first album, the humans have forgotten that they are aboard a spaceship, and in later albums Druuna keep forgetting that she's trapped in a Dream Within a Dream which is trapped in a telepathic Hive Mind which is trapped inside a crazy computer. The third album starts with the words "In the beginning there was chaos. Then God created the supreme being... first among all creatures: Himself." This turns out to have happened quite recently, but one need to question the concept of "universe" anyway.
- One alternate continuity for Old World of Darkness takes place on present-day Earth in a universe where time itself started only 20.000 years ago but wasn't created. Instead, Earth evolved. Yes, Earth itself, not just life on earth. It was a mnemonic evolution rather then a biological one. In this setting, physical reality is a mirror of the human mind's conception of reality, not the other way around. The planet started out as small and flat, later grew round, and now a whole universe is popping up around it in accordance to mankind's ever-growing consciousness.
- The magic spheres of Mage: The Ascension was always there, the 42 first humans were mages. Since linear time hadn't been invented yet, they were also each other's ancestors. shapeshifting was early, too. Much later, when heaven and hell came into existence, people wouldn't reincarnate anymore. So the Illuminati created vampirism to stay in the world.
- In the movie version of Left Behind, The Bible is literal truth, period. Critical thinking doesn't exist in this setting, and it works both ways. Protagonists who spent their entire lives with a secular world-view doesn't seem to feel any need for any explanation of how young earth creationism can possibly be true. In return, the rapture actually happening doesn't seem to give anyone else the idea that evangelical Christianity might be true after all.
- Avoided in the novels that the films are based on. Nothing is said about the age of the Earth, or the theory of evolution, other than Nicolae Carpathia believing in it, and stating that he (meaning Lucifer) was the first to evolve.
- In Good Omens, the Earth has only been around for 6,000 years and all the 'old' stuff in the ground is God's decoration.
- It also mentions that fossils are a joke that the paleontologists haven't seen yet. (A Brick Joke in progress.)
- In Strata, the main character designs planets for a living, and it is explained that it is important to give each planet a "history" to make it feel like something billions of years old rather than just a big lump of rock. At the end of the book it turns out that the entire Universe was constructed with this in mind and is only a few thousand years old.
- In The Hitchhiker's Guide to the Galaxy, the Earth is only 10 million years old (this may not sound young, but it's equivalent to thinking someone is 70 years old and finding out that he's 8 weeks old. It is also comissioned by mice, the true masters of our world.)
- Heinlein's Job: A Comedy of Justice has the world created recently, as a joke. As Satan puts it at one point, "My brother Jehovah is a bit of a jerk." What bothers Satan about the world is mostly that Jehovah stole most of the design. (It turns out that all this world-making, by a whole host of divine beings, under the review of another class of beings described as being "as far above me as I am above you" is all some cosmic artistic expression. As Satan explains, "This isn't about justice. This is about art.")
- The Short Story Evolving Conspiracy by Roger McBride Allen gives a nice metaphor for the postmodern approach: In order to make it seem that someone has slept in a bed, what would be the best way to achieve this? Actually sleeping in said bed. And God, being the master over space and time, did just that in 4004 BC.
- Played for laughs in S.P.O.C.K's song Alien Attack: It starts out as a straight case of the "Science is wrong" approach, ranting about how geology is just a theory that shouldn't be trusted. After thus establishing the character as a creationist conspiracy theorist, the concept changes. It turns out that they are not talking about the earth being young (which would have made more sense from the first lines). Instead, they are talking about how the dinosaurs actually survived the extinction level event by fleeing out into space. Now they are back, and furious that the humans evolved and took over their planet in their absence.
- "Alien, alien attack. They. Want. Their. Planet. Back."
- The Old World of Darkness is young, ironically enough.
- Nobilis has a characteristically odd version of the Jerkass Gods approach. The apparent age of Earth joins all other logical scientific principles in being the world's own delusion, called Prosaic Reality. It keeps mortals entrapped via continual Cosmic Retcon.
- The reason for this strange situation also bears mentioning: A couple of thousand years ago, an Angel came to Earth. He was so offended when he saw a very large dinosaur defecate, he wiped them from the face of the planet. Prosaic is evidently the world-spirit's attempt to create a reality where such horrifying things at least happen for reasons more comprehensible than a god's whim.
- Despite the fact that they're delusions, these are not a bad thing. Yes, they're lies hiding the true wonder of the world from humanity... but the true wonder of the world is rather inimical to human life and sanity—there's a special and dangerous kind of insanity that plagues non-miraculous beings that suddenly discover the Prosaic World is a lie through direct exposure to miracles. Few people can function with the knowledge that everything is alive, and at the incomprehensible whim of a god, they might not just be turned into a cat, but have suddenly never been anything except a cat.
- While not all that young, the Earth of the Nephilim gameworld is only a few million years old. The various secret societies have manipulated 'science' to disguise the real nature of reality from the lowly mortals.
- In the French edition, perhaps, but the English adaption used the Indian Yuga calendar, explaining Earth as being 4 billion years old. The difference is that it was formed by the reflection of sunlight off the other planets (and the Moon) all directing toward a single point, which formed the Earth's core and soon after the rest of the Earth. Animal life is the result of moonlight and direct sunlight struggling against one another.
- Exalted uses a variant of this, with the back-cover explaining that Science Is Wrong about pretty much everything in general and the age of the world in particular.
- The Parody Religion of Last Thursdayism claims that the Universe was actually created last Thursday, and any memories or evidence of events before that were created at the same time.
- The schism known as Next Thursdayism claims that the universe hasn't been created yet, and what we think is happening now is just false memories we'll have once it exists. Of course, some might argue that both sides are heretics: The Universe was created Last Tuesday.