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How Civilizations Can Spread Across a Galaxy
New submitter kanweg writes: If you look at the Milky Way at night, it appears not much is changing. But over time, stars get closer and further to each other. Coryn Bailer-Jones, an astrophysicist at Germany's Max Planck Institute for Astronomy in Heidelberg, found that of 14 stars coming within three light-years of Earth, the closest encounter is likely to be HIP 85605, which now lies some 16 light years away in the constellation of Hercules. It will get a close as the Oort cloud.
This could be a (very long-term) method for human or alien civilizations to practice star hopping. Why travel 16 light-years through space when you can just wait until a star with a suitable planet gets close enough that you only have to cover the last stretch with an artificial spaceship? Take your time for a thoughtful response; it will take another 250,000 to 470,000 year before the close encounter.
This could be a (very long-term) method for human or alien civilizations to practice star hopping. Why travel 16 light-years through space when you can just wait until a star with a suitable planet gets close enough that you only have to cover the last stretch with an artificial spaceship? Take your time for a thoughtful response; it will take another 250,000 to 470,000 year before the close encounter.
no
Also, wouldn't a star near the oort cloud mess up our entire solar system?
Let me just blacklist you in AdBlocker and I'll get back to you. Oh and with regards to the topic, well you'll have to wait a whole lot longer for a suitable planet than any old planet. Unless you got terraforming so under control you can build your own planet it's a lot easier to go where you at least get an earth-like rock to start with.
Live today, because you never know what tomorrow brings
Whether or not life still exists or even can exist on Earth that far in the future is an open question. I seem to recall reading somewhere that the Sun will change output significantly enough by then to (potentially) render our planet uninhabitable by life as we currently know it. I suspect intelligent life in other star systems will face a similar test of their patience if this is the method they choose for interstellar travel.
Any species that is willing to wait 250,000 years to avoid a 16 LY trip would never get to space at all. A race needs the drive to challenge obstacles and overcome them if its going to make it to space, not look for excuses to not try.
Especially since the Earth is only 6000 years old.
Our life spans are so short compared to the distances and time periods associated, and we're doing such a crappy job with our "solo" space vehicle, Earth...
If you can survive 3 light years in space, you don't need a planet. That's a long time interval - would we even survive on EARTH that long, as a species? Guess we'll see.
I think the human race is ill-suited to be "hopping" anywhere there isn't already abundant resources set up for us to exploit, grow fat on, ultimately choke upon or exhaust.
If we were able to solve all these problems, humans would be so far advanced from where we are now... the idea of hitching rides on random planets to travel will no doubt be obsolete (not to mention, patience-requiring like nothing humanity has ever set out to do since we were simians) and perhaps the paradigm of physically colonizing galaxies will prove itself pointless - what's the end goal, after all?
I very much doubt that NASA's budgets will get any better over the next 450,000 years.
I seem to have slipped a digit or two . . .
Virgin Galactic is taking deposits for reservations now.
If you aren't part of the solution, then there is good money to be made prolonging the problem
This seem to be a impractical and unlikely way for civilization to spread. You have to have a civilization to spread at the same time as the star (with a habitable planet) happen to be that close. (And thats habitable too an civilization that could travel to oort cloud distances.)
But in geological time frames it might be a way for (carbon based) life to spread. A star coming close would mess things up and spread asteroids and dirt everywhere, Some of them carrying the "seeds" of life. With the numbers of stars in our galaxy and the time frames involved ot kind of have to happen at some point/time in our galaxy.
Screw thinking about hitching a ride. The Oort cloud is too damn close. Am more worried about the huge gravitational forces of a star coming that close disrupting planetary orbits. Won't the orbit of the earth to be altered to a noticeable extent. Talk about climate changing events. I realize the Oort cloud is far out there in human scale but on a star system scale it's relatively close, hell Sedna orbits out past it and the sun has enough gravity to pull it back in. Does anyone know what the expected outcome of such a close flyby would be?
Am guessing the Oort cloud will be no more. But will we loose or gain planets, etc. My astrology forecast depends on this information.
Dunno. I think a real spaceship might be more practical.
First Post.
If you've got the technology to make a 3 light year journey you're not going to wait hundreds of thousands of years when you could make the 16 ly trip in a fraction of the time. Even with current technology we could theoretically make a 16 ly journey in somewhere around 1,000 years.
Any species that is willing to wait 250,000 years to avoid a 16 LY trip would never get to space at all. A race needs the drive to challenge obstacles and overcome them if its going to make it to space, not look for excuses to not try.
I assume you're basing this on a sample of zero. I honestly don't know how you can justify making any assumptions about what a race the survives 250,000 years might or might not do.
Pfft. Work smart, not hard.
250,000 to 470,000 years in the future...sounds about right.
by ebacon (16101) Alter Relationship on Friday January 02, 2015 @06:35PM (#48721439)
by thegarbz (1787294) Alter Relationship on Friday January 02, 2015 @06:35PM (#48721445)
It little behooves the best of us to comment on the rest of us.
"stars get closer and further to each other"
"It will get a close as the Oort cloud"
First time submitter? Hope it's the last.
If you hurt anyone your reputation will be damaged and with it the ability to travel.
I imagine our descendants in that amount of time will live underground, but otherwise seem to be like the "society" in Mad Max. They will be the last remnants of us, and will try to kill even that.
i would think that if another star decided to get close enough to perturb the oort cloud, we may have other issues to deal with.
---
Is this the MPAA? Is this the RIAA? Is this the DMCA? I thought it was the USA!
would i get there before the 250,000 years it takes to get earth a bit closer?
Yes, but three lightyears is not "near".
Yes, but the review was of those stars passing within 3LY. This one apparently reaches perihelion within the Oort cloud, which is a lot, lot closer than 3LY. Like, a couple of orders of magnitude closer. From what we think we know of it anyway, which is what I'm assuming the article is basing their definition of within the Oort cloud" on.
It's a nice idea, but the Drake equation probably gets in the way. Even if it passes close enough for some kind of generation ship rendezvous, what are the odds of it having an M-class planet?
"Take your time for a thoughtful response; it will take another 250,000 to 470,000 year before the close encounter."
For a moment I thought we'd really have to rush things.
Minus interstellar travel, we *are* the vorlons. Or hadn't you checked the news recently?
Hey, we've already survived at least 1.2 million, or at least so says that newly discovered "oldest known stone tool". Of course we weren't exactly modern humans back then, but neither will our descendents be a half-million years from now. Assuming they're still around of course, but that seems like a good bet - we're an incredibly adaptable species, I rather doubt anything will be able to wipe us out completely. In fact wiping out even 99.9% of the population would solve a LOT of problems our civilization is currently facing, while still leaving twice as many humans alive as were around when we were living as hunter-gatherers a scant 12 millenia ago.
--- Most topics have many sides worth arguing, allow me to take one opposite you.
no need to wait that long, 3 other stars in the next 60,000 years will come less than 4 lightyears away
http://simple.wikipedia.org/wi...
note how alpha and proximy centauri do the Elvis thing and leave the building from 10,000 AD onward
HIP 85605 will come within 8,000 AU of the Sun, still quite a distance, but VASTLY less than 3 light years. The blurb was also incorrect, this close pass will be in about 40k years, not 250k or more as stated (though perhaps this is a difference in sources, I don't know). 8,000 AU is something we could probably bridge with some advanced tech. For scale Voyager 1 is now at approximately 200 AU after 36 years of travel time, meaning it will take just shy of 2,000 years to reach this distance. It is certainly feasible to build a larger craft and fly it at 50x this speed using say fusion power, still only a very tiny fraction of C but yielding a trip time on the scale of a human lifetime. A little beyond our current engineering, but something similar to Daedelus, for instance, would suffice.
So, the idea isn't crazy. Its not that big a stretch of the imagination to think that true interstellar travel in the classic sense is simply infeasible. In fact it really is fairly difficult to imagine from an engineering perspective, there are technical issues so vast that they may well be insoluble, or only solvable by making compromises that are just not acceptable or limit such travel to very infrequent probes or something. That would leave close approaches as the single exception.
"Malo periculosam, libertatem quam quietam servitutem." -- Jefferson
...that our species (and civilization) will even be around in a quarter-million years?
I kinda doubt it.
Cloned foods give the statement "We had that last week!" a whole new meaning.
I have to imagine someone has already written a story with a similar concept, but it seems like a cool idea would be to slowly accelerate the sun itself to go to a star of interest, so you could get VERY close to the target system for examination while the whole solar system followed along for the ride...
It seems like you could accelerate slowly enough over a long period of time it would not bother the orbits of anything much. Or perhaps it would, and therein lies the story!
"There is more worth loving than we have strength to love." - Brian Jay Stanley
"Why travel 16 light years when you can just wait 300,000 years?"
Because no human plan requiring 300,000 years to bear any fruit is worth very much, and there's no good reason to believe that we have the 300,000 years to wait.
i would think that if another star decided to get close enough to perturb the oort cloud, we may have other issues to deal with.
What, like sentient stars? Yeah, I would imagine that could cause some issues. Who knows what kinds of havoc they might decide to wreak?
Rogue stars ejected from the Milky Way would drag their planets into intergalactic space.
"470,000 years" Yeah most civilizations probably don't last that long.
"If any question why we died, Tell them because our fathers lied."
Instead of making the big lead from star to star. You can make smaller leaps from comet to comet.
How long do you assume the 16 LY travel will take when you are comparing them?
The odds of a star having a lifeless planet with an oxygen rich atmosphere is pretty close to 0. Earth's oxygen was a result of life.
what are the odds of it having an M-class planet?
Not needed. We just need enough metal to build a Dyson Sphere. Any rocky planet, or even a few moons can supply the raw material. People shouldn't get so fixated on inhabiting planetary surfaces. That is not necessary or even desirable.
Then send millions of tiny capsules full of extremophiles like water bears towards nearby potentially habitable stars. The energy requirements are too ridiculous to think that we'll be lucky enough to move any significant amount of mass out of here barring crazy new technology. And I'm afraid I think we'll hit quite the opposite of the singularity--I suspect we'll see more of an S curve, as we discover the various fundamental limits in physics.
If we can become patient enough to make Earth a sustainable habitat for 250,000 years of high-tech civilization, then we have a pretty good chance of star-hopping whether on our own across a 16LY jump, or waiting for convenient systems to pass by.
If we can't hold space-travel tech together for even 1,000 years, I doubt we'll be very successful with any star-hopping endeavors.
Do any of these stars have planets? Because otherwise, there is nothing to land on when you starhop to them!
(This would have been a good point to discuss in the article!!!)
Humans begin the civilisation 6000 years a go where We invent writing. In 250,000 years We will be extincts or We will travel faster than neutrinos
Ceci n'est pas une Signature !
I tell my friends in China, why bother coming to United States? Just wait there, and eventually the North America will come to Asia by subduction. It's slow, but it sure beats paying $$$ for a plane ticket.
wouldn't a star that's by the oort cloud possibly change pluto / charon's orbit and possibly even earths?
would be a real b1tch if we ended up circling closer or further from the sun.
You mean DRMed/BRMed content, and water that the **AA and Monsanto-Nestle will sue the ass out of you for using?
The odds of a star having a lifeless planet with an oxygen rich atmosphere is pretty close to 0. Earth's oxygen was a result of life.
No problem. A decade or two before you launch your main starship, you fire off a probe with some lichens and cyanobacteria. By the time you arrive, the planet will be terraformed, with plenty of O2.
How does "fusion power" help it go 50 times faster?
Going fast is a mass problem -- you have to send a lot of mass out behind you to go really fast in space. Xenon propulsion using "just the sun" works pretty good at this sort of thing. Maybe you meant "fusion + a whole bunch of mass we can accelerate really fast and fire out our rocket butt?"
I come here for the love
Reminds me of the bit from A Tramp Abroad where the companions were planning to get from the mountain to the village by riding down on glacier.
Turned out to be faster to walk.
I can't say I've really given it much thought, but is there even enough material in the entire solar system to build a Dyson sphere in the habitable zone? Not to mention enough suitable material. It's going to take more than a planet, or a few moons, I would think.
Anyway, the article neglects that these suns probably have Oort clouds of their own, and a different ecliptic plane, which means theircomets would be coming at an angle Jupiter doesn't protect us from, and potentially at an exceptionally high rate of speed. What with our own comet adventures with Shoemaker-Levy 9 and Siding Spring, Earth interaction with a comet may be more likely than previously thought.
Help stamp out iliturcy.
I would not be so sure of that.
Help stamp out iliturcy.
"Take your time for a thoughtful response; it will take another 250,000 to 470,000 year before the close encounter."
Are you certain we shouldn't wait for something more timely, like blue smurfs flying out of my ass? Or perhaps a unicorn will come along soon, traveling at ludicrous speed of course.
Sorry, but this last statement in TFS basically put a fine point on this entire discussion, as if to say there's no point in discussing it at all.
is there even enough material in the entire solar system to build a Dyson sphere in the habitable zone?
One AU is about 1.5e11 meters. So a Dyson Sphere at one AU would have an area of about 2.8e23 square meters. If it was made of metal 1 cm thick (plenty to hold in one atm) then 2.8e21 cubic meters of metal would be needed. The earth contains (4/3 * 3.14 * 6.37e6 ^ 3) = 1.08e21 m^3, and is mostly metal. So you would only need to dismantle two earth sized planets to get the raw material to build a Dyson Sphere that could provide about a hundred million square kilometers of sunlit space to every person currently living on earth.
You need to check the pressure vessel equations. They are a function of radius. Required minimum thickness goes up with radius for the same pressure.
I don't know exactly how long it would take to terraform, and I can grant that it may be less than it took Earth to bootstrap an oxygen atmosphere, but I suspect it's much much much much longer than a couple decades.
Except that allows Congress a quarter of a million years to procrastinate, so that's just about perfect for them.
-Styopa
> I honestly don't know how you can justify making any assumptions about what a race the survives 250,000 years might or might not do.
You're absolutely correct. Unless we have specifically come across a situation before, we should say nothing about it whatsoever. We should use no forms of extrapolation, logic, induction, intuition or reasoning to expose various hypotheses for evaluation or contraindication.
Oh sorry - I mean the opposite.
Ask MultiVac.
And pre-life it'll be mostly carbon dioxide. We could work with that. Carbon dioxide plus energy can be processed into oxygen. Just means the colony might be stuck indoors or wearing respirators for a few thousand years. Annoying, but manageable.
A dyson sphere is grav-null inside. You'd need two shells, with atmosphere sandwiched between.
Currently we are covering the Earth with greenhouses because (drumroll) they provide a better (yes, I said it) environment for plants than nature does.
In 400,000 years, one can imagine most of the Earth covered by greenhouses.
Think about that for a moment.
So of course any space colonization will be based on greenhouses and not on terraforming or any other such nonsense.
A better suggestion might be Greg Egan, e.g.
https://en.wikipedia.org/wiki/...
https://en.wikipedia.org/wiki/...
"One AU is about 1.5e11 meters."
So you propose an environment that is baked 24/7 with the Sun at the zenith at all times? And you claim that that is desirable? Humans could only survive on that with pretty heavy airconditioning.
"If it was made of metal 1 cm thick"
Right. And it has to be airtight, it has to be somehow able to support plants, houses and streets - and withstand a constant bombardment of micrometeorites. All that on 1cm.
And it has to rotate at enormeous speeds to create gravity (which would not work at the poles anyway, so the poles would fall into the Sun).
"you would only need to dismantle two earth sized planets"
OK, then you have a huge sheet of 1cm thick bare metal. How many planets do we need to actually do something with it? Growing plants needs a little more than 1cm of soil. So the soil alone would take a couple of planets.
If we cover the Earth in greenhouses, we don't need to colonize another planet. We can just keep stacking greenhouses.
I'd like to think you're joking but it seems like you really think that. It is insane. Please stop thinking that terraforming is that easy.
You can spend some time on this website for an alternate future http://www.orionsarm.com/
This is not the sig you're looking for.
Well, that's the method I used last time and it turned out fine
What if all the good places are already taken ?
The same RV measures that are used to find exoplanets would apply to our own planetary system. And the nonsensical "Dyson Sphere" would react how?
E Proelio Veritas.
Seems like if we launched now, the attempt that waits 250,000 might get there sooner.
I am very small, utmostly microscopic.
With current technology, if we launched now we would probably end up in a situation where the relative motion of the star away from us would out run our spacecraft. Sure for now the star might be moving towards us... but by the time we got halfway it's orbit might be moving away from us again.
I am very small, utmostly microscopic.
I'm pretty sure that for any spreading of civilization a LOT of fucking will be of vital importance.
Machines don't constitute civilizations and clones are more like really elaborate fan clubs.
Sure, artificial insemination IS possible but that's the same result but without all the fun.
And the civilization that rejects fun is a dull and eventually dead civilization.
So... Fucking.
A LOT of it.
Mit der Dummheit kämpfen Götter selbst vergebens
Freeze a bunch of bacteria and DNA into particles the size of a grain of sand. Build thousands of probes that carry several hundred kg of this material, and launch them in all directions.
Once they get out of the suns gravity well, they spray the material as they travel along.
Maybe just for fun aim the probe itself to achieve orbit around a G class star, and hope the residue eventually makes its way to a habitable planet.
In 100 million years or so (not that long in galactic terms) Earth life might take hold somewhere else.
This is not very friendly for any other life out there.
I am very small, utmostly microscopic.
Any species that is willing to wait 250,000 years to avoid a 16 LY trip would never get to space at all.
You also have to consider the threshold for smaller groupings than entire species. For example, if my religious cult wants to go, it's a lot cheaper and safer to go with a smaller trip even if it takes a bit longer to get there. There might also be a lot more parties taking the thing seriously, if the nearest system is several times closer than the current 4.3 light years.
The question, is, with the disruption of the ORT cloud. What would be left of earth?. The ORT cloud with the asteroids are what gave us earth. It helped part the dust clouds that could feed the sun. And populated the interior with the lighter chemicals. How long before the influences of the incoming star system show up in our arena. To have an adequate earth protection mechanism, we must be space faring, or just say, humans die, I wonder which one our oligarchs will choose?
Sorry, where and how do we access the records of an foundered civilization? Shucks, look at what is inaccessible from the 1960's. 8 tracks anyone? I remember from the 60's working for a local public TV station, using a reel to reel recorder to tape interviews with local students and teachers for broadcast. None of that equipment that I helped to build would be accessible now. There were interviews with teachers and researchers from Montana complexes that were developing the newest reactors, and coming back to gm to continue their research.
A dyson sphere is grav-null inside. You'd need two shells, with atmosphere sandwiched between.
A Dyson Sphere is not a solid sphere. It is a swarm of independently orbiting objects, such as O'Neill Cylinders.
Have a good reputation by practicing ahinsa, and always helping and not hurting the civilizations one visits. Send a copy of your self to other civilizations and get them to build it, giving them detailed instructions. (Use error correcting codes for the instructions.) In return perform same service for others with good reputations! Using this method one can cross space at the speed of light or better. You can cross space at the speed a message can travel.
If you hurt anyone your reputation will be damaged and with it the ability to travel.
Right up until you meet a civilization that's intent on destroying your civ's reputation (and possibly going on a genocidal rampage) for whatever petty resource or idealistic goals they see fit.
And would you really want to create a set of instructions to build humans ... perhaps just so they become slaves or a tasty snack for the aliens on the other end?
Make sure everyone's vote counts: Verified Voting
And it has to rotate at enormeous speeds to create gravity (which would not work at the poles anyway, so the poles would fall into the Sun).
That is not what a Dyson Sphere is. I think you have it confused with Ringworld.
A few weeks ago, I saw a diagram showing how the closest stars are moving over time relative to earth.
I can't find it anymore but it is somewhere on internet.
If we could get a spacecraft to even 1% of c, 16Ly trip could be done in 1600 years. So yeah, waiting for 250000 years does not make sense at all. Milky Way is only something on the order of 120kLy in diameter, in 250ky I would expect humans to colonize, or atleast send probes to most of it. And that is without any monkeying around with warp drives or whatnot.
If I am not mistaken, the galaxy should could be contain far more orphan planets than stars.
They are difficult to detect (with our current technology) but they could be a good way to leave the solar system.
A wandering planet would provide all the raw material needed to sustain life for thousands or millions of years.
Of course, there would be no sun but, hopefully, our civilization will be able to get almost free energy from fusion within a few decades.
> The hard part is getting up to speed, and slowing down at the destination.
The diffusion method I call "slow interstellar" doesn't require that. If you already live in the Sun's Oort Cloud, and another star gets close enough that the Oort Clouds overlap, you only have to match velocity, which is on the order of 50 km/s. After that you drift along with the other star, spreading to fill their environment, until another close stellar encounter happens. This method requires more patience than humans possess, though.
This stars whizzing by us are going fast. While the distance may be short, the energy required to rendezvous with a "nearby" star will be far greater than the energy required to travel to a more distant star that has a low relative velocity with ours.
What do records from a foundered civilization have to do with anything? (though if you want them we have plenty of records from plenty of civilizations that have collapsed here on Earth. Essentially all of them that kept records in fact, excepting the current handful that haven't yet collapsed.)
And if you can't play reel-to-reel or 8-track it simply means you're not trying very hard - scarcely a month goes by that I don't come across at least one such old player in apparent working condition. And it wouldn't exactly be difficult to build a reader from scratch given only the tapes, even if you had never seen so much as a cassette player in your life. In fairness though, yes - the vast majority of records of the last century will probably be lost, one of the downsides to using highly unstable recording media. Many of our paper records will survive though.
--- Most topics have many sides worth arguing, allow me to take one opposite you.
A dyson sphere is a structure for energy collection above all. If you want nicely habitable space, you build a ringworld so you can have at least a little bit of gravity (Though not very much, or it tears apart). Dyson spheres are for those who have energy-intensive megaprojects, like running a simulated civilisation or trying to broadcast a beacon the entire galaxy can detect.
Sigh. I always get tired of these.
Ok
You know that line about sufficiently advanced tech appearing as magic to a lower tech culture.
Well if we took or current tech Bach to cave men...
So where will we be in a thousand years?
I have no freaking clue.
Either dead or out in the stars.
Saying we can't go fast enough is kinda silly. Sure you and I can't. That does not mean they will never.
Now to wait 250,000 years for a planet to come close, than again to the next?
That is insane.
That's a let's wait till we evolve to do anything.
Not
Long before that planet gets near we will figure out a way to get there if we live.
Look at how far we have come how fast. Two hundred years they thought going faster than a horse would kill. Comoros, internet? Hell th best sci fi writers though there was air and people lived on the moon.
Do when people say we will never go that fast. Yeah yeah. They said that about cars trains planes. Everything.
I don't in the last bit doubt that at some point every light speed will not be a problem.
How long will that take, hours will out be done who knows. But it will happen.
If we don't kill ourselves first.
If you want nicely habitable space, you build a ringworld
A Ringworld is a science fiction plot device. It is utterly implausible, requiring material strength a trillion times higher than any known substance. You could build a Dyson Ring, but that would just be a step toward buiding a Dyson Sphere, which is made up of Dyson Rings.
Ideally we would send artificially intelligent machines who don’t mind a journey that takes hundreds of years to explore and begin building infrastructure thousands of years before any humans will arrive. Then when the star is at its closest there is a mad dash of humans to populate the system.
Do this every time a star is going to approach to within 4-5 LY and then from those stars when they approach other stars, and so on. It starts to seem feasible for the human race to overcome the vast engineering challenges of spreading throughout the galaxy. It would be difficult to get humans to put effort into something that takes more than a lifetime to accomplish though.
Personally I think if we just clean up our mess here on planet earth and grow up a little. (stop killing ourselves)... maybe some folk's would be more inclined to pay us a visit and share some tech. :)
Humans will never colonize another planet, get over it. Focus on paying your rent and getting what "you" want out of life. 95% of the earths population could care less about space, it's that 95% you will need to face when resources on this planet become rare. Think about that.
Its a matter of inevitability. To think that we could survive on this planet for 400,000 years after seeing what we have done in 200 is a bit of a pipe dream.
Your original post appears to be calculating the amount of material based on a dyson shell 5 cm thick. You'll find a swarm of independently orbiting 5 cm thick objects kind of challenging for habitation.
Those encounters between stars and their cometary clouds provide a very nice mechanism for spreading life from wherever it might have originated, and why there's life on every world with liquid water. Life on Earth no doubt arrived here via various space rocks and comets carrying bacteria or even simple multicellular organisms like tardigrades, which are well known for being able to withstand the conditions of space and even the impact with Earth when they get here. And worlds like earth are continually being re-seeded from space. The new arrivals are indistinguishable from organisms that are already here, so they aren't noticed. That also allows worlds to go through sterilizing catastrophes and have life return to them over and over again.
Scientists describe virtually everything that is alive as animal or plant. So, if you’re not a plant then you are an animal!
It little behooves the best of us to comment on the rest of us.
It only needs the impossible strength if you're spinning it for gravity. Though it'd still be a ridiculous thing to build, when s swarm of smaller (though still huge by current standards) objects is more practical and less prone to catastrophic failure.
No, it also has it own gravity and the suns gravity and the air pressure, also is not stable. Run the numbers. They are quite impossible. And really why would you want one. Lots of smaller traditional stations would work better anyway.
If information wants to be free, why does my internet connection cost so much?
A mega-project like that? Why would you want the pyramids? It's the way to say your civilization is now advanced enough to do anything they feel like, for no better reason than to show they can.
Doesn't change the fact that they are quite impossible. Interatomic bonds are simply not strong enough by many many orders of magnitude.
If information wants to be free, why does my internet connection cost so much?
I never get the practicality of the Dyson Sphere. They seem unbuildable, in my opinion.
A Dyson Sphere is not gravitationally stable around the star it orbits. In fact it cannot be said to orbit at all, and building a Ringworld still has the same problem. This is usually waved off with mumbling about "station-keeping rockets" or some such.
A Dyson Sphere also will not hold together in the required shell structure. The planets are mainly rock (silica), and gaseous elements. How these are supposed to bind together into a strong, stable surface just a kilometer (or less) in thickness is never explained.
It's always hazardous to guess at far distant technology. That said, the laws of materials and physics can fairly safely be forecast as durable and consistent.
"Willing to wait" is not the same thing as "able to wait".
If we have no choice but to wait, perhaps willing is the next best thing.
Or do you have the secret to FTL travel hidden in your pants?
If we're willing to think about travel on that time scale -- and colonization is the goal -- an effective means might be to send (instead of, say human astronauts) a big mix of freeze-dried microbes and plankton from collected from different environments on Earth and wait for our emissaries to land and evolve and get back to use. Maybe send some kind of generic instructions on how to get back to us.
You ought to patent your "Terraforming for Dummies in 24 Years" solution, you'd make a fortune.
Getting up to speed in any time to get someplace in a reasonable amount of time takes an enormous amount of fuel to maintain constant acceleration half way, and constant deceleration the other half. I remember seeing a graphic that the mount of hydrogen it would take to do this for our nearest solar system was somewhere in the realm of the entire mass of our Sun... So unless you having something that can collect enough material such as the aforementioned ramjet, effectively impossible. This is where things like ion drives come into play, however current (untested other than in a lab) technology, is so slow a rate of acceleration to be much use for anything unless improvements can be made. Again things like solar sails (I believe the Japanese were looking at possibly testing that), might work, however once you get far enough away from a solar source (and solar "winds"), its effectiveness probably isn't so great at interstellar travel.
Best to wait for warp travel :). Presuming that as time goes on better technology is developed, we would be in the weird situation that each new method might mean that newer travel would be constantly overtaking older travel...