I know it kind of hurts to hear, but the more I mull it over I don't think there could ever be a galactic empire like what we see in fiction. To be specific, I am referring to centralized galactic empires, or even federations of a few star systems. The crux of this theory is all because of Faster Than Light Travel or FTL, or lack there of.
My argument isn't about space colonization, it is about centralized government spanning multiple star systems. The colonization of distant star systems is very possible. We might technologically be able to do it within our own lifetime, even if humans never actual attempt interstellar travel for centuries. Without going into any great detail about the Drake Equation or the Fermi Paradox, many respected scientists believe that Extra Terrestrial life in the cosmos is possible. Some believe that there may even be intelligent life on other planets. Theories about how much life there could be, contrasted with the fact that we have zero evidence of ETs has left scientists and laypersons baffled.
Some scientists have worked out the math, believing that it might only take a million years to completely colonize the Galaxy using only sub light speeds. That figure may sound huge, but the Milky Way is only thought to be around 12 - 16 Billion years old. In two or three hundred years, a race could have set up colonies on a hand full of planets. Perhaps an Extra Terrestrial Intelligence, or ETI, has already done this, but how much contact could those star systems share?
Without Hyperspace, FTL, Warp Drive, or Ludicrous Speed the pace that we transverse the galaxy is a snails crawl in comparison to its vastness. Do date, every proposed method of FTL has been deemed improbable to impossible. Even the darling Alcubierre Drive, the closest theoretical parallel to the warp drive of the Star Trek Universe, would theoretically not only require an astounding level of energy to warp space time, some believe it would also utterly annihilate the target destination when the ship drops out of warp.
To create a Type 3 or Type 2 Empire one would have to imagine a need for swiftness in travel from system to system. Star Wars and Star Trek have Hyperspace or Warp Drive. Any emergency on a distant system can be addressed in days or weeks. A colony is under attack by another race, a natural disaster is destroying a distant city, a disease is hitting a far off star system, all these can be addressed by military, disaster relief or medical convoys. In the age of sail, transportation around the globe was at most in the range of months between locations. It could take nearly a year for a one way trip, or over a year for return trips, but nearly every location was accessible in the range of months. The distance and time between planets is much, much greater.
In the spectacular series, Firefly, travel times between colonized worlds are equivalent to Age of Sail, or even Wagon Train time scales. This is was about space cowboys after all. In this Verse, there is a tyrannical, centralized government spread out between multiple worlds, but it only works because this all takes place within one massive and complex star system. There are five stars total, but they all orbit one massive white super giant. While such a system may be improbable, containing dozens of habitable or terraformable planets and moons, these worlds could still be traveled to using sub-light speeds with acceptable time scales. The Earth has no such neighbors that we know of.
Of our top five closes neighbors, Proxima Centari and the binary Alpha Centari A and B are all about 4 light years away. Bernard's Star is 6 ly, Sirius is 8.7 ly, Epsilon Eridani is 10.8 ly and Tau Ceti, our closest solar equivalent is 11.8 light years away from Earth. The time scale for traveling these distances at sub light speeds is plausible, not in months, but in years. Due Einstein's understanding of Relativity, we know that speed and can alter time. Light speed may technically be the limit to how fast things can go, but relativity will start adding time dilation even as you approach a fraction of the speed of light. How fast we may ultimate be able to travel will also depend on how much time dilation is deemed acceptable, and also how much energy it would take to achieve that fraction of light speed.
What I am ultimately getting at is, there would be no way to centrally govern multiple star systems, let alone a whole galactic empire. Say we could travel half the speed of light, ether consistently, or as an average from a gradual accelerating / decelerating method of propulsion. To visit a planet in the Tau Ceti system, which has a star very similar to our own Sun, and may have the closest earth-like environment, would take almost 24 years. That time table is withing a human lifetime, even for a return trip. If there was a colony in that system, how could Earth (or other homeworld) mandate any policy or administrate? How could aid be sent? If a system were under attack by an alien race or separatist system, how could a military be sent to defend the colony? If if the Empire were more totalitarian, how could it send a military envoy to maintain order and keep the systems in line? Perhaps most importantly, with such vast distances and time traveling between systems, how feasible would it be for commerce to be exchanged between the core world and outer systems? That last one might be the biggest factor, and also hits on why interstellar colonization might always be tough projects to fund. Much of the exploration and colonization in the modern age were all about commerce and profit. Setting up colonies in Jamestown, Virginia was meant to be a business venture for England. The Spanish conquest of the Americas was fueled by the lust for gold and silver. With out FTL, there would never be a time when an interstellar colony is meant to turn a timely profit. We may still gain in scientific discoveries, and quench our human need for exploration, but any hope for profit beyond our solar system would be such a long term investment, it would likely never attract investors. And such projects would be quite an investment.
In the novel, Lockstep, by Karl Schroeder, one fix to this idea of vast distances and travel times is to have the entire galactic empire in cryosleep at the same time, or lockstep with one another. Both people on ships, and people on planets would hibernate for long stretches of time in unison. With travel times artificially shrunk to human scale, the empire is able to maintain influence. I have not yet read this book and despite some clear issues with this idea, I am told that the novel addresses many of the problems one might see with such a universal hibernation directive, including what happens if not everyone says in lockstep. Definitely a book for my reading lists. For the real world, we still don't have any kind of viable cryosleep or hibernation technology available, so the only real option is generational ships for interstellar travel.
Does that mean we should not go? Absolutely not. Future generations may have different priorities. Fiction is full of ideas where a new home world is necessary because we mess up this one. Tragically, we are doing well on the first part of that scenario, but are nowhere close to where we need to be technologically to attempt a mass relocation. I don't even think that would be a viable solution. It would always be cheaper and easier to simply take care of our Biosphere. I am still one who believes that we need to reach for the stars as a civilization, find new worlds, boldly go where no one has gone before, even if there isn't an economic motivator. The majority of Earthlings do not agree with that.
Even if we could not branch out a centralized ruling power or federation of support among various star systems, we could still seed humanity though out the cosmos. Seed colonies could set up generational ships to distant star systems. Each ship would not only be able to produce and replicate its own goods and equipment, but even other ships. These great generational ships would be massive and incredibly expensive. They would almost be massive space stations hosting possibly hundreds of people. The raw materials required to build them would necessitate the mining of asteroids in our solar system. We are clearly far away from this level of technology, and very far away in regards to public opinion for funding such endeavors. Perhaps in the future I will talk in more detail what one of these generational ships might be like. there have been several concepts by scientists and engineers who also are compelled by the idea of interstellar travel. For shorter trips, several crew members would be born, some might die before the destination is reached. For longer missions, several generations would be born and die off before the ship reaches the destination. None of the original crew would survive a long distance interstellar mission. The colonist of those new worlds would be the descendants of the original explorers, themselves never having experienced their own home world. These seed worlds might have a mandate similar to that of it's home world, a constitution where it will start out with a similar set of laws, but it would have complete autonomy to evolve independently. Perhaps other colonies will be set up and be funded in ways that contrast with home world governments. People looking for a different form of government from where they came from, just like the Pilgrims at Plymoth rock traveled to the new world to create a new society based on their believes. Some of these colonies might begin as separatist in nature to begin with, never intending to stay in contact with the home world.
Any Seed world would only have limited contact with other systems, and technically one might be able to travel from world to world, but the cost associated with such distances might leave each system almost completely cut off from one another. Even radio communication would be limited to the speed of light, and just a message sent could take many years to send or receive. Exploration might be an isolated venture for interstellar travelers; spreading humanity and technology though the galaxy, but only sending limited and delayed information back.
If the Military Contractors who lobby for endless wars instead lobby for space exploration, not only would the rate of global war and suffering greatly decrease, we would placate that industrial complex, retain all the jobs associated with it, and put that effort to reaching out into space.
The Final Frontier.
