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I have a problem, in a story I'm thinking about writing, it is very far off into the future (let's say around 7000 AD if there has to be a number) and mankind has basically moved on to it's next stage and has begun exploring the far out universe. For some mysterious reason our solar system has been "locked" and mankind can no longer get into the solar system where our species was born and many have tried and failed but it seems it can only be "opened" from the inside.

I have been thinking about this for a while and I cannot find out how I can lock my solar system. And by lock I mean no ships, people or objects can enter into the solar system. Or if they try to enter they will be destroyed/severely damaged. Also it doesn't have to be impossible just extremely difficult.

One of the reasons this is so difficult is because I do not want to just use a force field encapsulating the solar system. Or some sort of massive ship blockade that shoots anyone who comes near. I don't want to limit my answers at all but these both seem like they would be very easy to eventually get past and difficult to maintain.

If anyone has any suggestions on how I could accomplish this I would be extremely grateful. (Also no magic. Sorry.) You can use any known technology or theories to help answer this.

EDIT

My original question was put on hold because I was unclear so here are the specifics.

The human race over the next 3000 years has become extremely advanced using genetic engineering to become biologically immortal, created incredible strong and light materials never before conceived, wormholes, FTL travel, etc. And the human race has spread throughout the universe using this technology.

Over the next 1000 years there is an intergalactic war. The human race is split into "tribes" most experience a devolution period because of their genetic enhancements they evolve much faster to adapt to the planets they live on. And lose a large amount of the technological knowledge they once had and basically have to start over.

Around 7000 AD some humans have found evidence that they came from earth. And they go out and try to get to our solar system. Unfortunately during the 3000 years when humans experienced there perfect evolution something has been set in place to stop anything from entering our solar system by the perfect humans.

I need that something to leave the solar system mostly intact/unharmed and keep anything from entering the solar system.

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closed as unclear what you're asking by Mołot, Hohmannfan, John Dallman, vsz, JDługosz Nov 10 '16 at 12:31

Please clarify your specific problem or add additional details to highlight exactly what you need. As it's currently written, it’s hard to tell exactly what you're asking. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

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    $\begingroup$ "You can use any known technology or theories" seems to mesh poorly with "very far off into the future" and "mankind ... has begun exploring the far out universe". We don't even have particularly plausible ideas for how to get to the nearest stars in any reasonable amount of time (meaning that we arrive not long after your stated timeframe). We can come up with ideas that might work given some set of assumptions, the way Star Trek's warp drive works in-universe, but they are hardly going to be based on what we know or are able to theorise about today. $\endgroup$ – a CVn Nov 9 '16 at 9:50
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    $\begingroup$ You need to describe what tech they have in 7000 AD. if it is after World War 4 and civilization was restarted in year 2500, they may well be in their steam age now. Or maybe there was no more big wars and they are advanced beyond our understanding. Or anything inbetween. $\endgroup$ – Mołot Nov 9 '16 at 10:15
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    $\begingroup$ Maybe a Dyson sphere? $\endgroup$ – Feyre Nov 9 '16 at 10:29
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    $\begingroup$ If the "lock" on the solar system can only be "opened" from the inside, are there humans on Earth or anywhere in the solar system? if there are, there is, at least, one obvious solution to the problem. Apart from figuring out how to "lock" the solar system in the first place. $\endgroup$ – a4android Nov 9 '16 at 10:59
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    $\begingroup$ @MolbOrg "with speed near speed of light there are plenty of ideas" Sure, but how many ways do we have that would allow approaching the speed of light with any spacecraft that is not made purely out of fuel? $\endgroup$ – a CVn Nov 10 '16 at 8:41

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An Einstein-Rosen (E-R) bridge has been established that surrounds the solar system. Any spacecraft attempting to enter the solar system will pass over the E-R bridge will emerge somewhere else in the universe.

A wormhole or "Einstein-Rosen Bridge" is a hypothetical topological feature that would fundamentally be a shortcut connecting two separate points in spacetime.

enter image description here

It seems reasonable who or whatever "locked" the solar system with an E-R bridge would make this obvious by arranging the exit point from the bridge somewhere close to the solar system. Arriving somewhere billions of light years away wouldn't help at all.

Also the on-off switch controlling the machinery responsible for the E-R bridge is presumably located inside the solar system.

An Einstein-Rosen bridge is a well-established concept in general relativity. It's not unreasonable to assume the technology of AD 7000 or that of even more technologically advanced sapient species will be able to generate them.

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    $\begingroup$ While a wormhole is indeed scientifically possible (according to our knowledge so far), it is next to impossible to actually create one. The reason is not the technicalities involved, but that it would take unbelievable amounts of concentrated energy to build one. We are talking about converting the mass of entire planets to create a short lived, short-sized wormhole. In order to create a wormhole that envelopes the entire solar system, I think you would need to feed it the mass-energy of entire milky way. $\endgroup$ – Youstay Igo Nov 9 '16 at 12:55
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    $\begingroup$ OK. I was wrong. It doesn't take the mass-energy of entire planets, but actually the mass-energy of entire stars to create a small wormhole for a few seconds. For a solar-system sized wormhole open continuously, the mass-energy of an entire galaxy might be less. You'd probably need the negative energy equivalent to the mass-energy of at least a dozen milky-way sized galaxies. This forum discussion might help: physicsforums.com/threads/… $\endgroup$ – Youstay Igo Nov 9 '16 at 13:02
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    $\begingroup$ @Anoplexian: I don't think you understand what dark energy actually is. It is nothing like any other form of energy that we know of. And it is pulling the universe apart. How can you even use this energy at all? Also, dark matter doesn't even interact with normal matter at all and it is impossible to see or touch it let alone convert it into energy. And lastly, even if somehow some advanced aliens are able to collect the negative energy required to open a wormhole this size, there is no way of condensing it all around something the size of our solar system. No, not even in 7000 AD! $\endgroup$ – Youstay Igo Nov 9 '16 at 18:05
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    $\begingroup$ @YoustayIgo You can say that it's impossible, but in 2000 years, we've accomplished such a large amount, that by over tripling that time, it could be possible. How? I have no idea, but that's something for someone with an active imagination to dream up. It may not be possible with our current understanding of physics but keep in mind that science on that level is by no means an understood field. $\endgroup$ – Anoplexian Nov 9 '16 at 18:12
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    $\begingroup$ As OP requests, magic is off the charts. What you are suggesting (somehow capturing dark energy/matter equivalent to the mass-energy of at least 6 milky way galaxies, converting it all into negative energy, and condensing it all around our solar system) is pure magic by the time this question has been asked. While we all are very open to extreme ideas, the ideas must be at least theoretically plausible. As in, the idea has a firm scientific base, even if the technology of putting that idea into action is not available. The idea you have presented is even lacking in theoretical realms. $\endgroup$ – Youstay Igo Nov 9 '16 at 19:37
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Although you say you want it to be sort of "locked away", I will bring something a bit more "out there" (pun intended) into the mix, to have a different angle on the problem. What about...

They forgot where it is

At some point, as your humans traveled out to reach for the stars, over the aeons that went by, they simply forgot about their former home. Navigating in space is hard.

Even in a single galaxy you can get lost easily if you don't keep proper records. Maybe some virus fried the main navigation databases? Or a minor civil war destroyed (most) records of where they came from.

Now, you can still have some small group know the location (and use it for whatever purposes). But it's more like a myth than fact. Maybe some even try to find it and fail horribly, while some find it but are not believed because the establishment denies the existance?

As I said, maybe this won't work at all in your setting, but I wanted to give you something else to think about.

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    $\begingroup$ That was one of my first guess. Also, if the solar system can be moved, it could just be lost or hidden elsewhere. $\endgroup$ – Kii Nov 9 '16 at 14:44
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    $\begingroup$ "They forgot where it is" first thought that popped in my mind: Battlestar Galactica. And they made that (which at first glance seems pretty boring and unimpressive) work wonderfully by building around it a mythology with men, machines and gods. I mean how much more awesome can it get when you realize mid season that the man created machines have more answers about the origin and religion of men. $\endgroup$ – bolov Nov 9 '16 at 16:22
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    $\begingroup$ This answer is part of the backstory for the Foundation series, and especially the plot of Foundation and Earth. $\endgroup$ – jhocking Nov 9 '16 at 22:37
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    $\begingroup$ This answer and its comments are contrary to the prescription in the question which was, basically, humans can't get into the solar system. Not that they can't find it. $\endgroup$ – a4android Nov 10 '16 at 1:01
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    $\begingroup$ New angles can be useful. But only if you don't stray too far from the question. It's a fine art knowing when that is. $\endgroup$ – a4android Nov 10 '16 at 7:16
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As in Michael Kjörling's comment, we have no idea what form of travel you're using, so it makes it difficult. There are no known technologies for space travel, but I can speculate based on existing sci-fi.

Here's a few examples based on the method of travel:

Wormhole Gates (Eg Stargate/ X/ Cowboy Bebop) or Mass Drivers (As used in Mass Effect): Onboard IFF (Identify Friend or Foe) beacon signals are required to access the system via the relay. If a ship without the required signal uses the gate/driver, the destination coordinates are modified. Eg: Ship without IFF accesses the relay/gate. Instead of being sent to Earth, the ship is sent into the gravity well of a nearby star. (This was actually used in Mass Effect 2 but an "Iris" as used in StarGate would be equally effective.)

For ships that use their own ftl drives: A generator that disrupts any ftl travel (Kinda like the Interdictor-Class cruiser in Star Wars but inverted). Ships can enter the field at ftl but not exit ftl while in the radius of the field. Perhaps even trap them in "warp".

Viral infection: A virus broadcast that corrupts any data relating to the system. Or one that disables any foreign ship's life support and comms.

The biggest shield ever: If all else fails encapsulate the entire system in a barrier similar to those used by the Ur-Quan in Star control 2.

The list of possibilities is endless, none of these are original by any means but could work as good starting points.

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    $\begingroup$ The Gate system or Mass Drivers for FTL sounds the best and most realistic. Say that with Normal FTL, it takes a very long time to travel to our Solar system possibly years or more even at FTL, but with the gate, its a few days at most. But say someone shuts Earths portal down, so now its like a Bluetooth device trying to connect to a Phone that ran out of battery, impossible. It requires someone from earth to turn it back on, but you can still get to earth, though its very difficult. Matches Criteria Perfectly. $\endgroup$ – Ryan Nov 9 '16 at 16:30
  • $\begingroup$ @Ryan Exactly, a gate or relay is the easiest way to restrict travel. $\endgroup$ – Lu22 Nov 9 '16 at 16:52
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Orbital laser cannons

A series of solar powered laser cannons have been deployed in various solar orbits (inclinations and distances). (Two should be enough to provide full coverage, but as many as you'd like can be deployed.) As soon as any ship is detected entering the system, they fire a beam as strong as they can at it. Any allowed ships carry transponders that allow the cannons to recognize them and hold their fire.

How is this different from a blockade?

It isn't, but a blockade like this is really the only viable option. Space is big. Really, really, really, REALLY big. Any kind of wall or obstacle is doomed to fail, and topological shenanigans like wormholes have energy requirements that are so far beyond reason that they are hardly worth considering.

But what about maintenance and ease to pass?

Not a problem. Solar powered laser cannons should fall somewhere between 'trivial' and 'entirely trivial' to produce for a civilization that can ply the stars, and an arrangement where worn out cannons are simply decommissioned and left to drift should be perfectly viable, especially if production can take place off-world (such as using resources mined from the asteroid belt), and if the production can be automated (which it probably can), the lock can maintain itself for what is for all practical purposes perpetuity.

Second, fully automated cannons of the required power would be near-impossible to evade, since there is no stealth in space, but depending on the constellation not entirely impossible to evade. They would also allow interstellar debris to flow through the system unimpeded while aggressively eliminating anything else. Even BSG-style FTL jumps would trigger immediate reaction and destruction, unless crazy things like jumping into atmospheres are attempted.

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Seal the solar system off behind warped spacetime.

This is the closest we have to having a plausible theoretical basis. It's commonplace to use a 2-dimensional description of spacetime for laymen, so let's go with that. Imagine the famous rubber sheet that's used to describe gravity; now imagine taking a piece of that rubber sheet, pushing it out into a 'bubble', then twisting it to seal off the neck. You end up with a little bubble of spacetime, with no path that can lead into it. The solar system can continue to exist in this pocket universe for as long as you need.

Turn Sol into a white hole

This is kind of out there. I don't know if you want the solar system to be intact after whatever was done; if you do, this probably wouldn't work. But if you're okay with a little bit of handwavium, this could be an option.

A white hole is a time-reversed black hole. They're theoretically allowed by General Relativity, but there's no theoretical method to create one.

A black hole is a point of intense gravitation that no energy or matter can escape from. A white hole would be a point of intense antigravity that constantly spewed out energy and matter, but no energy or matter could enter. There would literally be no path in the universe that would lead to the interior.

Convert the whole system into dark matter

This is kind of out there, since we don't know what dark matter is or whether the very notion of converting normal matter into it is possible. Dark matter appears to be matter that only interacts with our universe through gravitation. Most theories of dark matter suggest it would be some kind of exotic particle or particles that lack interaction with electromagnetism, the Strong force, or the Weak force. There are suggestions that there could be a whole periodic table of dark elements out there that we simply never interact with.

Converting the system into this type of matter could leave it internally unchanged - hydrogen changed into dark-hydrogen, oxygen becomes dark-oxygen, etc - but still cut off from the 'normal matter' universe.

This option comes closest to 'magic', since it requires you to make up the laws of dark matter out of whole cloth - but it is an option.

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    $\begingroup$ I'm in favour of topological shennigans, as my answer testifies, so your version deserves a nod. The Sun as a white hole would only keep anyone out of the Sun, but not the solar system proper. Also, it might tend blow away the planets as an unwanted side-effect. Conversion to dark matter is fine, somewhat 'magical' (full marks for inverted commas around magic), but not quite science enough. The old-fashioned shadow matter concept works better for this disappearing trick. $\endgroup$ – a4android Nov 10 '16 at 5:19
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How about something using the concepts of constructive and destructive interference of waves?

Place several wave emitters around the inner reaches of the solar system emitting very specifically modulated energy ("energy", pick your medium) waves. These emitters are placed and designed so that, within the solar system, they interact destructively and cancel each other out, but on a boundary radius around the system, they combine constructively to cause a massive energy output, causing it to be impassable by the technological level of the returning humans. For instance, you could use vibration waves, and literally shake ships that try to cross the boundary apart.

This allows scope/plot development for new technologies to develop and allow exploratory designs to cross the threshold, furthering your story. The fundamental concepts are already used: when you get a vibrational feedback on the touchscreen of your smartphone, one of the methods for doing this is by constructive interference from vibration emitters on the edge of the screen - where you press you get constructive interference, everywhere else it's destructive.

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    $\begingroup$ Heavens to Murgatroyd! The traditional explanation for a force-field resurrected. This goes back to when space opera maestros like E E "Doc' Smith, John W Campbell, Edmond Hamilton and Jack Williamson were belting out two-fisted action to stop chlorine-breathing slime-monster invaders in their tracks, back in the super-science epics of yore. $\endgroup$ – a4android Nov 10 '16 at 5:25
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    $\begingroup$ @a4android, hah really? I didn't realise it was ever used in that way. Strictly speaking using it to create a force field is a bit rich - a physical barrier could never be formed - but one through which building materials would be put under extreme stress is reasonably feasible $\endgroup$ – Ieuan Stanley Nov 10 '16 at 7:25
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    $\begingroup$ For science-fiction, it is plausible enough as an explanation for a force-field. Whether it would work, ah there's the rub. But, yes, breaking building materials is feasible. Good to see an old SF concept revived once more. $\endgroup$ – a4android Nov 10 '16 at 7:45
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An Asteroid Belt

Something happened after they left, and the outermost planet (which was extremely large) broke apart and turned into trillions of tiny fast moving chunks of rock that would destroy any ship that tried to enter or exit. Any ship that enters gets hit and breaks apart increasing the problem.

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    $\begingroup$ Debris orbiting in the vicinity of "an outer planet" would be relatively slow. Additionally, even if the planet destroyed were the mass of Jupiter and ground to dust, the particles would be spectacularly far apart. $\endgroup$ – dotancohen Nov 10 '16 at 11:04
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Antimatter Mines

After a major intergalactic war in the 52nd century, antimatter mines were commonly used as a tactic to restrict movement in much the same way as mine fields and IEDs are used on Earth today. These mines are completely undetectable and will cause the subject to annihilate on contact.

These proved to be a very effective deterrent during the war and Humanity's home solar system was abandoned due to large remnant fields of these mines.

Today, only a small number of individuals know the exact whereabouts of the mines as the knowledge was passed down through generations and protected as a top secret. Without guidance from these individuals (often involving huge cash payment) nobody dare attempt to navigate the area.

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  • $\begingroup$ Could downvotes please explain why. Can't improve without constructive criticism $\endgroup$ – Darren H Nov 10 '16 at 12:15
  • $\begingroup$ One problem with this is that space is really, really, really big - magically obtaining an extremely large amount of antimatter, converting it all into into tiny antimatter mines and spreading them into a "minefield" sphere covering the boundaries of solar system would still mean that they're very spread out, millions of miles between each mine. You're likely just to drive through it without hitting any of them. If you send many ships, maybe one of them will blow up. That sucks, but it's not a total blockade. $\endgroup$ – Peteris Nov 10 '16 at 12:50
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I suggest locking them out the same way you get locked out of your house. The house really isn't that hard to get into, but there is a price for using alternate methods of entry. That could be more interesting than a space wall alone.

With a house you might leave a security system on and forget the password, maybe to remember it later. Or you might forget your key and need to break a window, and find the key you left under a rock. Either way the real barrier is damage to the house or the police/security.

You could have something preventing access (a door or walls), like an internal security system that would destroy the ship, or maybe the solar system, or a Dyson sphere, or something of just enough importance to merit consideration, which could easily be disabled, but if the crew disables or bypasses the security system (like breaking the window on your house) there is a risk that an external security system will interfere. Maybe self replicating nanobots, or if we're really that far in the future, self replicating nano bots that became organic 'space bugs'.

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Navigation jamming or redirection. To travel far distances navigation by computers are necessary so have the technology to jam or redirect navigation with the solar system so that anyone traveling close to or within the solar system gets redirected into the sun or something.

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Your idea reminds me of background of EVE online game.

What happened in the story (if I remember well) is that when humans became able to easily travel across the solar system they developed very fast, so fast that in no time they found themselves out of resources.

That's how they started to get interested in the natural wormholes that appeared in the solar system and led to random places far beyond the system, providing new planets to exploit. This was nice but dangerous as nobody know when these holes could close. That's what led to the development of gates built around these holes in order to maintain their stability.

Everything's fine. Until one day a huge wormhole opened in our backyard. First explorers tell stories of a whole different galaxy, so plentiful of resources that it is called New Eden, but so far away that it is impossible to determine its relative location to ours.

In their greed, humans build two huge gates, one on each side of the wormhole (Called Adam on "our" side, and Eve on the far one, hence the name of the game).

But after one or two hundred years of frenzied exploitation and technological evolution, the Eve gate collapsed, leaving millions and millions of humans completely isolated from the solar system. What happens next is irrelevant to the subject. But the idea could suit you, mostly if you like the idea of space exploration based on accidental and static wormholes. You just have to say that it is the gate to the solar system that collapsed and there you go.

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The sun has become unstable due to an attempt by Elon Musk's great great... grandson to build a dyson sphere to harness all the Sun's energy to prolong heat death and stop hostile aliens being able to find us. This went wrong and now the sun is emitting constant solar flares that will destroy any electronics on a craft making it near impossible to get to Earth.

Other ideas I would rate are the an outer planet becoming an asteroid sphere (not a belt as that be bypassed above and below) or a white hole appearing in the Sun's place.

Alternatively visible objects only make up around 5% of the universe's mass the rest is made of dark matter and dark energy. There could be large groups of dark matter round the edge of the universe which means any ship going towards them is turned round as comets are by our Sun or alternatively if going fast enough they can get past but don't have enough time to decelerate down before flying past Earth (space is a vacuum so the best way of slowing is firing thrusters in the opposite direction of their motion which takes a while if starting at the speed of light)

Sources: https://en.wikipedia.org/wiki/Dyson_sphere +some youtube video I remember http://science.howstuffworks.com/solar-flare-electronics.htm

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A rogue automatic defense system that would just be too costly to disarm, so they have to wait for it to break down.

Maybe they found out too late the friend or foe program only recognizes people born on the home planet as friend and destroys everyone else. Maybe they only found this out after they left in generation ships.

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Since my first impulse, an expanded Dyson sphere / swarm, was already mentioned, another suggestion:

It got stolen (or otherwise displaced)

That's some theft, isn't it? Through Technology or an unlikely natural phenomenon, Earth (or the entire Sol system) is no longer where it is supposed to be. No debris (or some, but later to be discovered to be decoy), thus humans know it's not just destroyed, but it's definitely not just cloaked but really elsewhere. Thus begins the quest to find it again...


Disclaimer: Inspired by the end of Dan Simmons'

Endymion

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Since the premise is nearly impossible with current technology, I can only give you crude guidelines. You would have to build your system in detail by yourself, but here are some founding ideas.

1- There is a wide layer of comets encircling the solar system. The layer is several thousand miles thick and a couple hundred thousand miles wide.

2- Someone has manufactured a series of self-replicating drones, programmed to mine minerals from planets and asteroids, create copies of themselves and are programmed to shoot at anything that looks like a spaceship.

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    $\begingroup$ You may need to rethink your layer. If "The layer is several thousand miles thick and a couple hundred thousand miles wide."; what's stop any spacecraft going over it or around it? $\endgroup$ – a4android Nov 9 '16 at 10:53
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    $\begingroup$ the layer has to be spherical $\endgroup$ – Mihai Răducanu Nov 9 '16 at 11:04
  • $\begingroup$ Traversing distances of "several thousand miles" takes on the order of seconds to minutes with any spacecraft that is meaningful to discuss in our solar system, let alone anything that can leave the solar system. $\endgroup$ – a CVn Nov 9 '16 at 12:45
  • $\begingroup$ The issue with going around a several thousand miles thick layer of comets is that spaceships travel at a frighteningly fast speed and it takes a lot of fuel to turn or slow down the spaceship at those speeds. Also, travelling at such frightful speeds, it is not easy to make precise turns. For example, a single 5 kg chunk of rock/ice has the potential to critically damage the New Horizons spacecraft, considering how fast it is travelling. $\endgroup$ – Youstay Igo Nov 9 '16 at 12:52
  • $\begingroup$ Apollo travelled about 11.0-11.5 km/s during the translunar coast. Taking "several thousand miles" to be 3,000 miles ~ 4,500 km, traversing that distance in about 410 seconds or just under seven minutes. Look at our solar system's asteroid belt; it is extremely sparse. You'd have a really hard time explaining where the material to make such a huge, un-navigable debris field comes from, as well as why it doesn't coalesce over time. $\endgroup$ – a CVn Nov 9 '16 at 13:08
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Religion/superstition/hysteria will do it without any technological help. Case in point, Bermuda triangle. A few initial missions failed (for whatever mundane or whatever one-off fantastical reasons) and crew lost resulting in this sector of the galaxy becoming branded unsafe. Further, if it requires a big enough expedition to reach here (ensuring not just everyone can take one's private space equivalent of car and fly out here), no one would want to spend money on it. Stigma/taboo/fear + financing issues would deter a lot of things.

Alternatively, the sun has gone red giant ahead of the schedule. The population of earth has moved to the outskirts of sun's range but no one living outside of the solar system knows this. They try to go to the original earth and get fried by the sun or they assume that earth died and there's no real reason now. If the population still needs to be living on the original earth then they could be living underground with help from their fancy 7000AD tech. Again outside is bad enough because of the red giant enveloping it so that no ship can survive past Jupiter (and again they don't even know if earth still has life).

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Singularity Ring

Such a ring could be of arbitrary size and collapse the fabric in hypergeometric space to create a sub-universe. Imagine blowing a bubble inside another bubble for an analogy.

Since we are using hyper geometric space, you can use the existence of separate universes to explain the energy required to create the Ring.

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Von Neumann Machines

Some mad science project in the past went bad and now the solar system is infected with self replicating nano-bots, slowly turning everything into grey goo. They aren't capable of FTL travel themselves but can easily hitch a ride with any capable starship so the entire system is strictly quarantined.

I think it satisfies all your constraints. It's not impossible to enter the system, just massively risky. No magic and the tech is both conceivable and relatively low tech for the year 7000. It also adds an interesting back story for how and when the infection started and the panicked migration that took place afterwards.

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  • $\begingroup$ do not like that GG thing in general, but to cheer u up, upvoted. GG like stuff may make good defense system using matter of a star system and energy of that system. Such a system may make penetration not an easy task. What I would like to see it a bit more sophisticated description of such system, even if I can imagine it myself. Overall GG is valid approach to prevent anyone access to the system(with limitation but still), and it may be out of the control and evolve countermeasures and such, if it designed for that, and star energy allows do a lot of things on system scale. $\endgroup$ – MolbOrg Nov 10 '16 at 15:09
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Space junk

In only the last 50 years we've already created an orb of junk around the planet. According to NASA:

More than 500,000 pieces of debris, or “space junk,” ... orbit the Earth. They all travel at speeds up to 17,500 mph, fast enough for a relatively small piece of orbital debris to damage a satellite or a spacecraft.

The rising population of space debris increases the potential danger to all space vehicles...

By the year 7000, it's entirely possible that we foolish humans will so fill the rest of the solar system that it would simply be too dangerous to fly around in it.

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    $\begingroup$ -1 for not really plausible, with that much junk it would essentially be a Dyson Swarm. $\endgroup$ – Zan Lynx Nov 10 '16 at 1:26

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