When making a timeline for a fictional universe, there are many Speculative Fiction Tropes that tend to pop up, especially if it is based on the real world. This list notes them in the order they (typically) appear. Its purpose is both to help with World Building, and to help when writing a crossover.
This list also includes nonfictional historical and scientific "facts" that are the basis of many fictional stories, such as the "A meteor killed off the dinosaurs" theory.
Related to Hollywood History, but more detailed.
- Billions of Years Ago:
- Creation of the Universe — Either the Big Bang or some Supreme Being (or both, they aren't mutually exclusive) creates the universe (or recreates it, see End of The Universe below) approx. 13.5 Billion years ago (according to the latest theories.)
- The Earth forms. (Scientific theory — Approx. 5 Billion Years ago.)
- Life begins on Earth. (Theory — Approx. 3 Billion years ago.)
- Might possibly have been influenced by Precursors.
- Millions of Years Ago:
- Eldritch Abominations lived on Earth, but left, were destroyed, hid, or were sealed away. Ex: Cthulhu Mythos.
- The dinosaurs evolve.
- Approx. 65 million years ago, an object (a meteor, comet or spaceship) crashes on Earth, killing off the dinosaurs... except in certain hidden places.
- 1 Million B.C.:
- The human race evolves.... or is created by someone or something. (Note: current scientific theories state that mankind evolved somewhere between 150,000 BC and 50,000 BC, so actually setting something 1 million years ago will get you flak from academics.)
- Advanced civilizations such as Atlantis may have existed, but were wiped out before recorded history. Often a source of Lost Technology.
- Ancient Astronauts arrive.
- The Time of Myths:
- Humanity spreads over Earth and develops several cultures.
- Beings of great power are worshiped as gods. Some may actually be aliens in disguise. Example: Stargate.
- Some humans are taken off planet and end up colonizing other worlds, then forgetting about Earth. (This explains all those Human Aliens.) Ex: Again, Stargate.
- The Dark Ages:
- Witch Hunts (and/or the magic going away) cause supernatural beings to either leave for a Magical Land or hide their existence from normal humans.
- At some point, an Alien Non-Interference Clause is enabled in space, preventing more aliens from coming to Earth — except for criminals and castaways. Ex: Men in Black.
- The Recent Past
- The Industrial Revolution both enables Steampunk technology and / or makes sure that any lingering hints of magic that hadn't disappeared during the Dark Ages has gone away now or is going deep into The Masquerade.
- World War I and World War II occur. Reckless time travel around this point is almost guaranteed to make sure that Hitler wins.
- Oh, and don't bother trying to assassinate Hitler to prevent this either, clever dick; you'll just make things worse. Trust us on this.
- Of course, an Alternate History where Hitler wins might just pop up anyway without any 'helpful' time-travellers messing around with things.
- The Present:
- The Near Future:
- Before FTL is invented:
- After FTL is invented:
- Very Far Into the Future: (let's say, for the purposes of symmetry, A.D. One Million)
- The End of the Universe: