Here’s my draft timeline for the 30th-40th centuries that I just sent my group :
c. 3000 C.E. - The Legion of Super-Heroes is founded, defending the United Planets from threats both internal and external.
3098 C.E. - The Khundian Empire joins the United Planets, ending centuries of tension and conflict. The United Planets now encompasses more than half of the inhabited worlds of the Milky Way Galaxy.
3105 C.E. - The peaceful times (known to historians as the ‘Pax Galactica’) result in the disbanding of the original Legion of Super-Heroes, after more than a century of continued existence. It was believed that the exceptional individuals in the Legion could do more under current conditions by acting as leaders and agents to inspire change on their own homeworlds. Legion leader Wildfire oversees the final shut-down of the Legion’s Metropolis headquarters, alongside long-time colleagues Brainiac Five and Blok.
3190 C.E. - A spatial fold-gate of Coluan design is put into place, connecting the Milky Way and Andromeda galaxies, allowing conventional warp travel between the two in a more reasonable time-frame. The design would later be used to connect several nearby galaxies to the Milky Way.
3279 C.E. - An experiment gone awry at the Vidar Institute for Temporal Research cracks the time continuum. The Science Police are swamped as creatures from past and future eras bleed through into the present throughout the United Planets, though the focus of the activity is the area around the Institute itself, in Metropolis. Gyrel Dox, a female Coluan known as Brainiac Seven, hastily assembles a new incarnation of the Legion of Super-Heroes to deal with the disaster (the ‘Timequake of 3279’). The new Legion contains the chaos that erupts in the present, while Gyrel researches methods to repair the damage more permanently.
3280 C.E. - A moratorium is placed on temporal research by the United Planets Council, excepting only Gyrel’s work.
3289 C.E. - Gyrel and her Legion successfully repair the continuum, traveling to the terminus of each ‘time fissure’ and applying her techniques to heal the breach from the outside, in. One of the teams does not return after completing their mission, and a rescue attempt is deemed too risky - further time travel could re-open the fissures. Saddened by the loss, Gyrel disbands her Legion.
3290 C.E. - The moratorium on temporal research is lifted, but replaced with a number of restrictions. Time travel is explicitly forbidden and all experiments must be pre-approved by a council of United Planets scientists, for safety. The Time Beacon in Metropolis that once served to guide time travelers home is deactivated as a consequence of the decision.
3300 C.E. - As the galaxy heals from the effects of the Timequake, there is a growing discontent in the populace - a mistrust of scientific experimentation grows, justified in their minds by the disaster. Further, with no source of significant opposition to the United Planets, there is less impetus for research and development. As a result, the progress of technological knowledge begins to slow and stagnate.
3368 C.E. - The Sentience Accords are ratified by the United Planets, providing a formal framework for the recognition of non-biological sentience. Distinctions are made between Artificial Intelligences that simulate the appearance of true self-awareness, and Artificial Sapients, capable of directed self-modification and learning. The latter are accorded full citizenship rights in the United Planets.
3472 C.E. - The galaxy dubbed ‘MW-962’ is due to pass comparatively close to the Milky Way Galaxy. Exploration teams are sent, but astronomers observing the galaxy are alarmed when it appears to change directions, contrary to its mathematically predicted path, heading on a collision course with the Milky Way. This is the beginning of the ‘Rogue Galaxy Crisis’.
3473 C.E. - The Rogue Galaxy’s outlying dwarf galaxies begin to make contact with those of the Milky Way, and it is discovered that the Rogue Galaxy is inhabited by a previously unknown polymorphic species (the Zyrga) that combines mammalian, reptilian, and insectoid traits. Controlled by a powerful hive mind, they had all but wiped out the more advanced species of their galaxy, and now the Hive Mind’s vast psychic powers (fueled by the countless trillions of members) enabled it to direct the path of the Rogue Galaxy. The United Planets quickly mobilizes its forces, but the initial engagements are not promising - almost all end in defeat. At the front of the war, however, a new team coalesces - a new incarnation of the Legion of Super-Heroes. The Rogue Galaxy stops its advance, leaving it in a close, binary orbit with the Milky Way galaxy.
3474 C.E. - Due to the new Legion’s successes combating the Zyrgan forces, the United Planets gives them belated official recognition. The Legion and the U.P. Fleet are able to hold the line against the invaders, but resistance is too fierce to push them back.
3475 C.E. - The United Planets deploys new forces to the front - soldiers with genetic modifications including enhanced artificial metagenes, giving them greater endurance, strength, and durability. These ‘Hyper-Soldiers’ provide much-needed reinforcements, allowing the Legionnaires the freedom to work as a more agile intervention team, actively interfering with the Zyrgan hive-mind’s tactics and dealing with more conventional minor crises that could disrupt the war effort.
3477 C.E. - An elite unit of Hyper-Soldiers in a specially modified assault ship penetrate to the core of the Rogue Galaxy, detonating a Quantum Bomb that eradicates nearly all remaining intelligent life in that galaxy. More than 95% of the Zyrgans are instantly slain, crippling the hive mind irrevocably. Despite the success, the Legionnaires criticize the use of such excessive force, believing another way might have been found - and citing the deaths of those few civilizations in MW-962 that had not fallen to the Zyrgans. Public opinion, on the other hand, largely sides with the U.P. Command’s decision to order the strike, deeming the resultant losses as acceptable since it brought about the quick end of the war.
3478 C.E. - The Legion continues its existence beyond the war, cleaning up isolated pockets of Zyrgan predators that threaten innocent lives. They also work against space pirates and more conventional disasters, since the war has strained the United Planets’ resources and limited the government’s ability to help. Exploration of the mostly-dead Rogue Galaxy begins, as it continues to orbit the Milky Way.
3523 C.E. - The last original member of the third Legion of Super-Heroes resigns, and the team soon disbands once more - the subsequent recruits had no unity of vision for the team, and each has their own idea of how the Legion might be most useful.
3530 C.E. - Without the Legion, the people of the galaxy have few inspirational figures to lift their spirits in the still-devastated regions of the galaxy. With the falling morale, unrest increases and several worlds threaten to leave the United Planets if their needs are not addressed. The U.P. does its best to step up production of essential foodstuffs and equipment, shipping them out to the war-torn worlds with units of Hyper-Soldiers to guard them. The Hypersols, as they come to be known, are viewed as heroes of the Rogue Galaxy Crisis, and their presence serves to boost morale (as well as to quell dissent through implicit intimidation).
3612 C.E. - One of the dead worlds of the Rogue Galaxy is claimed by a group of android pilgrims, who dub it ‘Robotica’ and seek to establish it as a kind of Mecca for all artificial sapients. Robotica is granted provisional status as a U.P. member world, and confirmed as a full member five years later.
3833 C.E. - Deep within the Lunar labs of the United Planets’ Research Corps, an experimental artificial metahuman (Project Nexus) awakens. Possessed of vast power, it easily breaks free of the laboratory and flies out into space. This being, dubbed the ‘Ultimate Man’ by the press, passes near or through a number of United Planets worlds, causing chaos on each. More than half the population of Naltor loses consciousness as they are struck by a mass vision of horror; some never recover, and some awaken to find their prophetic powers gone. The cause of their vision is soon apparent - The Ultimate Man is on a direct course for Zerox, AKA Sorcerer’s World. Some evacuation is achieved, but the being moves far too swiftly and many of the students and teachers perish when their planet is shattered into dust. Magic emprisoned beneath its surface floods back into the universe.
With the destruction of Zerox, the Ultimate Man’s path becomes less directed and his speed less urgent - but it’s predicted that his path will take him towards Weber’s World, the artificial planetoid that serves as the center of the United Planets government. A group, led by J’onn J’onnz, the last Martian, is hastily assembled - a possibly final incarnation of the Legion of Super-Heroes to end the threat of the Ultimate Man. No visual record survives of the confrontation, but the Ultimate Man exploded as a result of the battle, creating a nebula of exotic matter and energy, less than ten light-years from Weber’s World. None of J’onn’s group is known to have survived, and they were all honored with statues on Shanghalla.
3834 C.E. - The United Planets’ troubles were far from over, unfortunately. The release of the potent magical energies stored in Sorcerer’s World awakened many new dangers that the U.P. was spectacularly ill-equipped to address. Complicating the matter as the return of the lost civilization of Atlantis from other-dimensional exile - the vast floating city in the Atlantic claimed dominion over Earth’s oceans, which meant that the planet no longer had a unified government. This called into question its eligibility for membership in the United Planets.
4001 C.E. - Today. Earthgov and Atlantis are still separate organizations, but the Earth remains a U.P. member, on provisional status. The two governments are trying to find a mutually agreeable arrangement - Atlantis wants access to Earthgov’s starports, and Earthgov would love to be able to lay claim to Atlantis’s magical knowledge and material wealth. For now, relations are friendly and a compromise that allows cooperation and coexistence has been achieved, but it is uncertain how long the status quo will be maintained.
The United Planets is still exploring the frontiers of the Milky Way, Andromeda, Rogue, and other galaxies, and dealing with new species, as well as members of known species who have decided to operate outside the law. They look to worlds like Orando and Naltor to provide guidance on magical matters, as well as the surviving teachers and students evacuated from Sorcerer’s World. The Hypersols maintain order where possible, and hold the U.P. frontier against external threats. Time travel is still outlawed, and the penalties for rogue experimentation in that area can be harsh indeed.
In addition to the more conventional threat of space pirates, and hostile species, there are a few interstellar warlords that have sprung up - combative groups united not by a single ruling species, but by a single ruling man or woman of great insight and charisma - and so, much more focused of purpose. Rumors say that one such warlord may even be a human, from Earth. On top of that, the Zyrgans remain a threat - scattered pockets of them survived the Quantum Bomb, and the United Planets military must remain vigilant to make sure they cannot amass a sufficient population to re-create their galactic hivemind.