I'm sorry. Firearms have been reinvented since inception. Vehicles have been reinvented since inception. Granted it took a little over 100 years, but yes, the mobile (cell) phone has been reinvented a number of times since then. (If I remember correctly, the mobile phone was patented and in use before the landline was patented and in use.)
There is nothing in quantum mechanics like that. Quantum mechanics exists in static space and time. There are interpretations of string theory that allow spacetime to rip, which could allow exotic particles through. I wouldn't use something we understand though, quarks can't exist by themselves.
You could start with your main character not knowing much at all (for whatever reason). He/she would then discover your world as the story progresses as would the reader. This would avoid the need for info dumps and encourage the reader to empathise with the character as they would both be equally unfamiliar with the setting. The MC would also have reason to ask many questions which would provide you with an excuse to provide details. Don't worry about how stuff works. What's relevant is how to work it. The method by which the transporter in Star Treck works has never been explained but people don't lose the plot every time there's a scene in the transporter room. Co-ordinates are typed in and a lever operated, that's all you need to explain. You don't need to explain how a faster than light propulsion system works but you may want to mention, that when it's initiated, everyone has to take to their seats as the ship judders and a standing person could fall and sustain an injury. Don't forget health and safety. High walkways should always have safety rails, (they only called it the death-star because of all the fatal accidents).
Well 500 Lightyears is relatively small in galactic terms (MilkyWay is 100,000 lightyears across, just for perspective). So I am gonna say that @Sack-a-Doo! concept is not too far fetched on Sat/Internet/Network. Though without the physics behind the comms sats, it will be slower than dial up in terms of sending/receiving info (and dial up was slow as molasses going uphill on an iceberg.). So unless you have an FTL travel/comms system that will work within the existing physics world, you might have to forego plausibility on some things. At least as far as keeping tabs on the people in the 'rural' world communities. Unless you have a scientifically sound reason that justifies such things. Warhammer 40K has an interesting way around this. But even the Empire of Man has trouble keeping its vast influence within the 'rural' planets in its control, and they are on a galaxy wide scale. So unless you give in to some of the more fantastic ways around such obstacles (FTL or extremely long lifespans) you will hit a few road blocks along the way. A radio transmission takes ages to cross space, so the people on planets in the outer rim would be dead by the time it made its way back to Earth. Hell you would need self sustaining ecosystems on massive ships, and go through many, many, many generations of populace just to make it 500 LYs. Warp Travel is theoretically plausible, but would be devastating to anything at the front of the ship. The gravity of chasing a synthetic black hole at FTL is not exactly the best idea in concept or practice. Seeing as you would destroy the planet of your destination by the immense gravity tides created by your means to get there in your space/time bubble at your rear, and the interstellar pothole at your front. C (light speed) takes an 'infinite' amount of energy and mass. Meaning unless your people/ships act as both waves and particles like photons do, then FTL and C are both out. You could manage to get possibly close to C, but even then it would take hive ships to travel the vast distances and have somebody at the end of the journey. In short you have to stretch a few things for it to work with any kind of effectiveness to the story. (I have Subspace travel but it takes hours/days/weeks depending on just how far you are going in my own Sci-Fi WIP, and it is limited to the Milky Way Galaxy. Humans use cryo as a way to counter long stretches of travel, and can get to a few million km past Pluto in approx. 6 months because they don't have the tech to travel in subspace, while other species do.)
@Cave Troll I've made the territories of aliens and factions intentionally cramped and small in comparison to the galaxy as to avoid ridiculous times with communication, So an advanced satellite network could do the trick to make it relatively quick like @Sack-a-Doo! Mentioned. @Aled James Taylor I love the idea of amnesia with the MC which cuts corners on the sci fi universe exposition, unfortunately I have 4 MC's who all have a different background (all different species.) And have distinct backgrounds and difference, so I'm wondering how we could possibly do that with 4 MC's.
I wasn't actually thinking of amnesia, although this would work well. You could make him come from a rural community of farmers who are not too concerned about issues outside their community. They've given your MC a specialised and limited education (so he knows all about farming but little else). You only need to explain things once so having more than one ignorant character may be problematic as since explanations would need to be repeated. We all have limited knowledge of things we're not familiar with. We're all familiar with helicopters; we've all seen them flying overhead. How many people would know what kind of engine a helicopter uses? How many would guess incorrectly?
