Time Travel: Mostly about Earth
Time Travel is an integral part of the Legion mythos, but here is what is established as Time Travel plots from the point of view of Superboy's late 20th century
//Note: many of these plot ideas come from things in the Best of Fenix anthology, which is just wonderful.// [1]
Rules of Time Travel
First Rule of Time Travel
There are natural Time Barriers that block the chrononaut will unless greater power is used to push against them. The strongest Time Barrier channels the cnrononaut to 512 years ahead of and behind current day. Using a "Class A" time machine will drop a contemporary chrononaut unto the 2480's or the 3500's.
Each Class after that will let the chrononaut get half again as close or twice as far away. Future Boy will build a Class B time machine that will reach 1024 to 256 years from Current Day. This gives a time travel range of moving forward to between the 3250's and 4020's and backward to a year between the 1970's and 2740's.
For the purposes of the Legion this is probably our real range so the GM doesn't go nuts. (Superboy/Superman acts as a personal Class B time machine, so he can reach the Legion on his own once he knows to try.)
Second Role of Time Travel
The further away from your time you initiate a change, the less likely that change is to stick. Truly powerful chrononauts can get close to their absolute now, which is where the real power is because you can make real changes to your "now". The further away you are the more likely the time stream will was over the changes or break into separate streams rather than change the absolute now.
This is essentially the Time Tourism rule built to accommodate all the delightful Superboy/Superman stories where he and Jimmy or Lois go back in time and have hijinks (some of these are listed below). For the Legion this means they can have similar low stakes but fun tourism/scholarship visits back to the past.
In terms of the future, the Second Rule of time travel prevents boostrapping technology. Jumping to the future to get better weapons/tech/answers to what we did in the past just doesn't work. You'll forget the key information traveling back, the tech won't work in the present, etc. That time working this way means that you can't use what is intended as an occasional side story generator as the the engine of an entirely rebuild campaign chassis is intentional.
Third Rule of Time Travel
That's for me to know and you to find out.
Earth's Ancient Past
9 to 23 AD – Wang Mang’s China
The period when Wang Mang was emperor of China, this is the far edge of Superman’s time travel. Wang Mang is one of Superman’s most bitter foes, seeing him as the embodiment of everything that is not classical China. Once Wang Mang learns of his existence and, by extension, the events of the next 2000 years he puts into place a two millennia conspiracy to restore proper culture to the world.
64 AD: Nero’s Rome
When Jimmy Olsen connects Superman a historian looking for specific critical information on the early Roman Empire, Superman agrees to bring Jimmy back to ‘get the story’. There they uncover a plot by ancient Egyptian cult of Ammut, (crocodile god of dreams) to replace Nero with a homunculus. When Egyptian magic reduces his power Superman is forced into a gladiatorial bout as Jimmy manages to reveal the faux Nero. The remnants of the Ammut cult are destroyed in the fire and the proper Nero returned to power. Superman recovers enough to return Jimmy and himself to the 21st century.
1174: Between the Second and Third Crusade
In the chaotic period between crusades – as crusader states intrigue against one another iafter the second crusade and Saladin gathers his power in the East – a group of crusaders following clues from an ancient Chinese scroll wake a huge red dragon. One survivor of the dragon’s attack on a crusader unit was Etienne of Navarre, as he and Isabo were travelling to Jerusalem hoping the True Cross could break their curse. They survive only because a red and blue angel appeared to defeat the dragon. 830 years later the Hawks relate the story to Superman and the Man of Steel travels back to fulfill the time loop, barely defeating the enraged magical beast. He strongly suspects this was a planned assassination attempt on him by Wang Mang. (Note that the Hawks don’t have their flight gear yet, as it was Da Vinci’s design)
Early 1770: Revolutionary Dating Triangle
Because part of me adores the old silly stories of Superman time travelling, Superman travels to the pre-revolutionary war period for a romance triangle between the forceful and passionate Mary Ludwig (future Molly Pitcher) and the beautiful Elizabeth Phoebe Griscomb (future Betsy Ross). Is this entirely illogical? Well, no, both women were alive and unmarried in 1770, but other than that yeah, it’s totally absurd. We are therefore doing it anyway. I think we tie this to a fictitious precursor event to the revolutionary war (the Boston Massacre is on March 5, the Golden Hill Incident is January 17, so it’s right in that time period). Two possible options are that this is a story of Superman when he was a boy and young Betsy Ross sews the first Superman costume for him to wear while preventing another massacre, or it’s another one of those wacky “Jimmy Olsen convinces Superman to time travel and they end up double dating Molly and Betsy” stories. Or both.
1881: Rockets in the West
Nikolai Kibalchich, a Ukranian engineer & anarchist, built the bomb that killed Tsar Alexander II. He escaped from prison, and the Russias, with a solid fuel rocket of his own design. Making his way to the American west he perfects his designs and tries to use them to foment more anarchy in the US but is defeated by a team up between Vigilante and the Hawks. (The Hawks now have their glider wings, but don’t yet have the full flight capability because they haven’t yet been upgraded by the Wright Brothers.)
1927: Arthur Conan Doyle
Towards the end of his career Doyle became deeply involved in the Spiritualist movement even as he perfected the art of modern detective work. He wrote about the latter in his fictitious Sherlock Holmes stories, and the former in his non-fiction accounts of discussions with his spirit guide and the completion of final novels by other writers who had passed on. In 1925 he predicted an enormous upheaval of earthquakes and floods in 1927, but later told people he and his spirit guide used the wrong calendar! This was the first rumble of the Mayan Apocalypse of 2012, forestalled by the work of Doyle, Vigilante (who was learning detective techniques) and Zatara (who was mastering his ability to speak with dead).
1931: New York City
The construction of new towers allows the ancient gods shadowy access to Manhattan, influencing people, manipulating effects, forming cults and otherwise trying to alter the world. Only the works of Zatara prevent moldy Babylonian gods from appearing in Central Park West to tear up the city.
1990s: Smallville
Superboy lives here, and strange things happen around the town, sometimes with secret time travelers.
2008-2030: The Justice Alliance of America
This is the time frame for the Earth 10 Stuff mentioned in the other tab
2130’s: The Arctic Circle
A series of enormous solar flares has shut down much electromagnetic tech and communications, and combined with existing warming trends to melt the polar ice and reveal a whole new landscape to the North. It takes place at closest future timeframe Superman can access and Vigilante is right in the thick of it because it’s a Western. A whole arc of the “Vigilante as immortal in other times and places” comic “Legends of the Vigilante” takes place here.
26th Century: Nostalgia and Stasis
500 years in the future, the only thing I know from here is that it’s where Reverse Flash comes from.
30th century: Legion of Super Heroes
It’s a full on bright Gernsback future where a group of teenagers use their non-human powers to emulate the super-heroes of the 21st century. The Legion was founded by Diskette, Miss Anima, Metal Lass, Mr. Music and Bubble Boy. Superboy is the 8th or 9th recruit, via by Future Boy’s time machine.