User blog:PitaKang/Funday Monday 3: What would an interstellar civilization look like?

What would a future inter-stellar empire look like? Would it be like the enormous Empire in Star Wars or the Imperium of Man in Warhammer? How would such an empire be limited by the so called "light speed barrier"? Is such a thing even possible? An interstellar empire in the future may not be possible, the prime reason for that being the "light speed barrier" that most science fiction franchises seem to completely ignore. But first, why is it impossible to reach the speed of light? It is because of Einstein's famous E=MC^2, which says that energy (E) is equal to mass (M) multiplied by the value of the speed of light (C=300,000,000 m/s) squared. (Overly simplified version) The reason that light speed is impossible is because when an object accelerates and the velocity increases, energy is increased. Because energy is increased, the mass is "increased". In reality, the mass is not truly increased, but inertia is increased and virtual mass is added. The more virtual mass is added, the more energy it takes to increase the velocity. Even more energy must be used, which means more virtual mass. This pattern keeps repeating itself until you would need infinite energy to reach the speed of light, since at the speed of light the "mass" would be infinite. Therefore it is impossible for something to reach the speed of light unless an infinite source of energy is found. A tachyon, on the other hand, is a particle with an imaginary number value mass that is always traveling at superluminal speeds. Because it has an imaginary mass, as the energy decreases its speed would increase. In fact, tachyons would require infinite energy to slow to subluminal speeds. Tachyons, since they are faster than the speed of light, would also not be visible at all. Tachyons have also never been found. If tachyons do not exist, superluminal travel is indeed impossible without infinite energy. Along with that, superluminal communications is impossible. Even launching a tiny ball at a fraction of the speed of light would require energy on an unimaginable level. So much of Halo's MACs, which would require 16,318,029,100,000,000, or 16 quadrillion joules of energy. Another possibility are wormholes. An oversimplified definition of a wormhole is a bend in space-time that would allow the travel of great distances without having to achieve superluminal speed. While theorized by Einstein, such wormholes have never been discovered, and even if they are, they would be an impractical way of travel unless you could generate wormholes next to your location and point the exit, which would take incredible amounts of energy. Also, a wormhole would bend both space and time, which would mean that exiting a wormhole would deposit you anywhere from 10 billion years in the future to 30 million years in the past. This would violate the grandfather paradox, the well-known paradox of "killing your grandfather, so you do not exist". But since FTL travel and communications is impossible, a future interstellar empire would be much, much smaller than in your favorite science fiction novels. Not covering more than an area a small percentage of the galaxy, that interstellar empire would be rather like the colonies and the empires hundreds of years ago. Getting colonists to other planets millions of light years away would take at least a million years at .99c, if enough energy was generated to keep up 99% of light speed. Furthermore, once the colony is established, communications would be a million years each way, since communication would go at light speed. It would lead to a colony completely isolated from its mother country, and it would develop on its own. Now, colonies in the solar system are definitely possible. Mars is only a few ten million kilometers away from Earth, and at 10% of the speed of light, a spacecraft could reach Mars in about 2 hours. At 1% a spaceship could reach Mars in 20 hours. Communications between the two would only take 12.5 minutes back and forth. So, a Mars colony would be very possible. Beyond that, however, travel would start to take months, again a doable journey. But at places like these, isolation would set in. The colony would develop its own culture and society totally apart from Earth. Eventually, it may even separate from Earth. Any hopes of expanding across the galaxy would be impossible. Contact with any alien species would be very improbable and any contact would be very slow, since the message that they would have sent out would be thousands to millions of years old by the time we have received it. So, an interstellar nation in the near future would not really be interstellar at all. Rather, it would be limited to inside the current solar system, and there may be pockets of colonies outside. One point that many bring up is time dilation. If a spaceship travels at 99.99999999% of the speed of light, time will dilate and the ship will actually travel to the future. This effect is observed in astronauts who are technically a few minutes younger than they should be. Passengers on spaceship traveling at 99.99999999% of the speed of light will have felt like they traveled for 5 minutes, but outside their ship, they will have traveled for 5 years. This would mean that travel between thousands of light years is possible because to the people on board only a few weeks or months or whatever have passed. Of course, on the outside thousands of years will have passed, but thanks to time dilation, the people inside the ship will not have aged that much and will be able to colonize. Conclusion: An interstellar empire/nation is impossible due to the FTL barrier. But isolated colonies that will eventually develop into their own civilizations and cultures are possible, which could lead to an unimaginable future where millions of separate, isolated civilizations exist, knowing that each other exist but not being able to reach them. A rather fantastic premise for a novel, actually.