How Civilizations Can Spread Across a Galaxy 272
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.
So /. joins the annoying music ads? (Score:4, Insightful)
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.
A species that patient isn't going anywhere ever. (Score:5, Insightful)
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Pfft. Work smart, not hard.
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Except that allows Congress a quarter of a million years to procrastinate, so that's just about perfect for them.
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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 civilizat
The financial math isn't any easier... (Score:5, Insightful)
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Passing Stars (Score:5, Funny)
Artifical Spaceship. (Score:5, Insightful)
Dunno. I think a real spaceship might be more practical.
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I think you lost your argument at "If we can make...". If it's made, it's an artifact - and thus artificial. And without the made part it's just a rock, not a spaceship.
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Why? (Score:3)
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.
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Note that this particular star is going to pass a bit over ONE lightyear away, not three.
On the other hand, 0.03c makes the 16 ly trip in less than 600 years. As opposed to a quarter million years.
On the gripping hand, it's useful to keep in mind that those stars are moving relative to us, and that over long enough timescales, our skies aren't going to be constant....
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On the other hand, 0.03c
0.03c? Are we talking pulsed nukes? Orion?
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No, same amount of fuel, 5x the time. If you can make the one journey and live enough (or support descendants), you can make the longer one. spaceships don't stop when you turn the engine off
Re: Why? (Score:3)
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perhaps algae can be farmed from waste and CO2. Keeping the lights on and keeping warm should be a very small amount of energy compared to the amount getting to even five percent of lightspeed would take
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You're half correct, it would take several times as long, but this is space travel, you don't need several times the fuel. The smaller Orion designs only have the craft accelerating for about 10 days. Any craft that can last a hundred years is in all likelihood going to have all of the capacities (long term energy source, on-board fabrication of replacement parts, crew replacement, etc) to last much longer with only moderate modifications. No doubt that the level of danger increases with the distance, bu
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It's nice to say that we'll have the technology to magic al
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Umm, no - you would presumably be coasting most of the way. In which case a journey 5x the distance at would take 5x as long with exactly the same amount of fuel. Or the same amount of time with roughly 25x the fuel (5x the speed = 25x the kinetic energy, and I'm assuming a propulsion system where fuel mass is a negligible fraction of the total vehicle mass).
Or with 5x the fuel (= kinetic energy for simplicity) you'd be traveling at ~2.24x the speed, and thus cover 5x the distance in 2.24x the time.
And I
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I'm assuming a propulsion system where fuel mass is a negligible fraction of the total vehicle mass
You seem to be forgetting about the propellant. Also, there's the Tsiolkovsky rocket equation. Plus you need the same amount of propellent for slowing down at the destination, which means that propellant mass = C * exp(exp(payload mass)).
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you're missing the highly necessary radiation and impact shielding. a sufficiently robotic civilization could send machines, but machines can't survive radiation either. their bits could flip, and cause a blue screen or a kernel panic. if you only shield the machines then you need only impact cushions of some sort, and there isn't a better material than layered graphene crystals which cost an order of magnitude higher cost than any other material and is currently so brittle a hand shake could destroy it
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That depends upon whether you spaceship is say an inside out engine. With an energy field generated around it to gather particles from in front of the ship and accelerate them around and past the ship to move the ship in the desired direction and that field to even be used to generate an attraction and or rotation within the ship to simulate gravity. A large colony like ship where the population only leaves to visit other places rather than remain. Of course one on their own does leave them exposed in the
Re:Why? (Score:4, Insightful)
Even with current technology we could theoretically make a 16 ly journey in somewhere around 1,000 years.
No, we couldn't. We don't have the technology right now to build a multi-generational ship. We don't even have the technology right now to send an unmanned probe that would still be powered by the time it got there. We don't even have the technology right now to build an unmanned probe that would shut itself down and bring itself back up after 1000 years. Hell, it's hard to find a motherboard from the 80's that doesn't need capacitors replaced before it can be booted up again.
Who knows what kind of technology we'll have in 300,000 years, though. And the closest the destination, the more likely something can actually get there.
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Even with current technology we could theoretically make a 16 ly journey in somewhere around 1,000 years.
No, we couldn't. We don't have the technology right now to build a multi-generational ship. We don't even have the technology right now to send an unmanned probe that would still be powered by the time it got there. We don't even have the technology right now to build an unmanned probe that would shut itself down and bring itself back up after 1000 years. Hell, it's hard to find a motherboard from the 80's that doesn't need capacitors replaced before it can be booted up again.
Who knows what kind of technology we'll have in 300,000 years, though. And the closest the destination, the more likely something can actually get there.
We probably could but it might take devoting the entire worlds GDP for a decade or so and there is noway that would happen. We need the technological advances so that it would approach affordability.
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We probably could but it might take devoting the entire worlds GDP for a decade or so and there is noway that would happen. We need the technological advances so that it would approach affordability.
I agree with you that there's a lot we could accomplish if we were willing to spend the money, but I honestly think we're still at the stage where this is a technology problem, not a resources one. I don't think we can build electronics that could function for 1,000 years, so I definitely don't think we have a system that can keep life support active for humans in a generational ship for 1,000 years...right now we're seriously questioning our capability of shielding astronauts from radiation on a trip to M
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No, we couldn't. We don't have the technology right now to build a multi-generational ship. We don't even have the technology right now to send an unmanned probe that would still be powered by the time it got there.
Actually powered may not be that impossible, they're experimenting with Am241 which has a half-life of 432 years, so even after 1000 years it would have ~20% of its initial power production. Do we have electronics that can last that long? Who knows. Voyager 1 was launched in 1977 and is still running, before Intel had even invented the 8086. I'm sure we can do better today if that's our design goal. It seems likely that if it can withstand ~38 years of interstellar radiation that the shielding and error rec
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>Even with current technology we could theoretically make a 16 ly journey in somewhere around 1,000 years.
If you consider Orion, 1950s tech, to be 'current' then it could be more like 200-300 years. What calculations did you use to get 1000 years anyway? Just asking because I love those sorts of calcs.
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"What calculations did you use to get 1000 years anyway?"
I'd always heard 100-150 years for an Orion craft to get to a Alpha Centauri, a lot of those calculations don't include the energy required to slow down for some reason (I think) so I multiplied the estimate by two (200-300 years). Alpha Centauri is about 4.3 ly from us so I divided 16 by 4.3 and multiplied that (3.7) by the 200-300 estimate to come up with 744-1116 years. Of course all of these numbers are probably based on the original 1960s Orion
Year of the Linux desktop? (Score:3)
cross space by cooperation! (Score:5, Interesting)
If you hurt anyone your reputation will be damaged and with it the ability to travel.
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Mod parent up -- great point! Some sci-fi books have explored this theme, with both bad and good results. Two examples:
http://en.wikipedia.org/wiki/A... [wikipedia.org]
http://en.wikipedia.org/wiki/T... [wikipedia.org]
Anyone know more?
well (Score:4, Interesting)
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.
3 stars come within 3.5 lightyears in 60K years (Score:5, Informative)
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... [wikipedia.org]
note how alpha and proximy centauri do the Elvis thing and leave the building from 10,000 AD onward
Do you really believe... (Score:2)
...that our species (and civilization) will even be around in a quarter-million years?
I kinda doubt it.
The real spaceship Earth... (Score:2)
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!
Are there any planets to land on? (Score:2)
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!!!)
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We now know, thanks to Kepler, that almost all stars have planets.
http://www.space.com/24894-exo... [space.com]
250,000 years to ... (Score:2)
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
let the earth do the moving for you... (Score:5, Funny)
Sam Clemens (Mark Twain) on a glacier (Score:2)
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.
Pointless conversation (Score:2)
"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.
While waiting (Score:2)
You can spend some time on this website for an alternate future http://www.orionsarm.com/ [orionsarm.com]
Re:"Take your time for a thoughtful response" (Score:5, Insightful)
Also, wouldn't a star near the oort cloud mess up our entire solar system?
Yes, but three lightyears is not "near".
Anyway, traveling 16LY is only trivially more difficult than travelling 3LY. The hard part is getting up to speed, and slowing down at the destination. The long coast in the middle is easy, and if you are going fast, it is time dilated anyway.
Re:"Take your time for a thoughtful response" (Score:5, Insightful)
Anyway, traveling 16LY is only trivially more difficult than travelling 3LY. The hard part is getting up to speed, and slowing down at the destination. The long coast in the middle is easy, and if you are going fast, it is time dilated anyway.
Getting up to speed is really really hard. So much so that you can largely forget about taking advantage of time dilation. Unless you can salvage a Bussard Ramjet [wikipedia.org] (current thinking is that it won't work) you are not going to get that fast. Traveling 3LY instead of 16LY means only having to reach 1/5 the speed to arrive in a "reasonable" time. That's a big help. It might be the difference between doable but hard and hopeless.
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Minor quibble: if a Bussard ramjet can't be built, how can you salvage one?
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Bring it through a portal from an alternate universe where it can be built.
Re:"Take your time for a thoughtful response" (Score:5, Informative)
Sort of.
Yes, if you assume that we'll be accelerating in all cases to .999c or something like that, then you're probably right, it doesn't matter as much.
However, if you are only capable of making it to .5c or .8c, safely, then it could make all the difference in the world.
At those lower velocities, the time dilation is not really all that much, and you'd not only have a trip that is longer, but the observer would also be experiencing a longer relative trip due to dilation being much less pronounced below .9c. The Lorentz factor at .5c is only 1.155. It only gets to 2 at .866c. Due to relativistic effects, our ability to accelerate to and then to maintain safe flight (such as your ship not being annihilated by hitting small particles of matter) at the higher velocities is very challenging, so assuming that relativistic time dilation can be counted on to even out the logistical problem is probably not warranted.
That said, if we have to wait 400,000 years for the "quick" jump to open up, I imagine we would have made the "long" trip thousands of times over by then. That interval is minuscule in geologic time, but an eternity compared to our current rate of technological advancement. (Assuming our present rate of advancement doesn't come to a grinding halt, of course.)
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Due to relativistic effects, our ability to accelerate to and then to maintain safe flight (such as your ship not being annihilated by hitting small particles of matter) at the higher velocities is very challenging
Somebody's never heard of a Deflector Shield.
What's the time dilation like at warp? I doubt we'll be worrying about speeds slower than light if we're ever traveling between stars (and the presumption that our knowledge of physics, with our not-even-500-years-of-electric lights infant knowledge, is absolutely correct and 50,000 or 200,000 years from now we won't have found a solution, is laughable on its face).
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I doubt we'll be worrying about speeds slower than light if we're ever traveling between stars
FTL is impossible. So forget it. Best you've got is time dilation. Either we will travel to the stars at less than c or we won't do it at all. I for one truly hope that we do it. Although clearly I won't be alive to see it.
and the presumption that our knowledge of physics, with our not-even-500-years-of-electric lights infant knowledge, is absolutely correct and 50,000 or 200,000 years from now we won't have found a solution, is laughable on its face
Unfortunately the presumption that it is incorrect in the sort of good way that you seem to be hoping is even more laughable. Physics rarely works to make things easier for us Just the opposite. It almost seems to have a grudge against whatever it is we want to do. If our theories prove t
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That said, if we have to wait 400,000 years for the "quick" jump to open up, I imagine we would have made the "long" trip thousands of times over by then.
True, but it's a matter of relative comfort. Do you want to do the long trip by canoe, or take the leisurly route via cruise ship (aka your home planet) for most of it?
Chances are, if nobody does it by canoe to prove it can be done, nobody else will want to invest in building a cruise ship at all.
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Chances are, if nobody does it by canoe to prove it can be done, nobody else will want to invest in building a cruise ship at all.
And if we have not bothered to travel 16 light years in 400,000 years of tech advancement then we probalby will have no interest in going 3 ly at that point either. We could head for alpha centauri right now if we had the will and the billions of extra dollars floating around.
First build the the ship at a Lagrange point. Then launch for our nearest neighbor. If we used an Orion drive the astronauts could be at Alpha Centauri in maybe 75 to 80 years. A single human lifetime. Unfortunately, unless we got very
I think you misunderstood (Score:5, Informative)
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.
How? (Score:3)
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?"
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Voyager was not designed to go fast, so going 50 times faster is not as hard as it sounds.
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Voyager was not designed to go fast, so going 50 times faster is not as hard as it sounds.
I'm sorry, but you have absolutely no clue about what you're talking about. Voyager used the major planets aligning to slingshot out of the solar system at speeds that no practical chemical rocket can reach. This is because to go faster you need to carry more fuel, but this fuel makes it even harder to accelerate causing an exponential relationship. Even just to match Voyager unassisted we need an entirely different kind of unproven technology like fission, fusion, antimatter, ion or solar sail being possib
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People will be living on near-absolute-zero ice balls with no local energy sources in the interstellar void instead of somewhere interesting for what reason?
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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.
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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.
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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.
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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.
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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.
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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.
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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 curre
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A dyson sphere is grav-null inside. You'd need two shells, with atmosphere sandwiched between.
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"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
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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
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Re:250,000 - 470,000 years to go . . . (Score:5, Informative)
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Oh, wait, is this what they call a hypothetical question?
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The Earth has several hundred million years, if not much more, of habitable time to for complex life such as humans. The era of the dinosaurs was 300 to 65 million years ago and a few hundred thousand years is just a blink of an eye compared to that kind of time span. It is very doubtful humans showed up on the scene at just at just the instant that conditions on Earth become inhospitable for complex organisms.
What's more doubtful is whether an advanced culture can survive for such a span of time. Insign
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Extrapolating human longevity based on that of the dinosaurs is vacuous because the mass extinction 65 million years ago was a random catastrophic event.
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I mentioned the era of the dinosaurs to put the time span of a few hundred thousand years in context of actually being fairly brief. I honestly don't know of any data to draw upon to extrapolate whether such a time span is reasonable for a technical civilization. Thus I'm open to hearing other's ideas on the matter.
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Your basic point is well taken.
Not all dinosaurs were killed. The tree variety made it.
So, catastrophic event, or evolution, or technical advances, ... we cannot predict.
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By random cyclically recurring, do you mean like synchronizing random noise?
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470k years is literally nothing on the time-scales required for a significant change in the Sun's energy output. Just for comparison, dinosaurs appeared 232 million years ago, and disappeared 66 million years ago.
Maybe not, but it's certainly significant on the human time scale. Neanderthals were interbreeding with humans [wikipedia.org] only 50,000 years ago, and only got their start between 200,000 and 300,000 years ago.
The average human contains between 60 and 200 individual mutations. Who knows what our descendants will be like 470,000 years from now?
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In 4.5 billion years the solar system has doubtlessly survived many such stellar encounters while keeping the planets in relatively stable orbits. Such encounters may dislodge an unusual number of comets that then rain down on the inner solar system (potentially causing other problems), but the chance of an encounter disrupting planetary orbits is almost negligible. Space is really that large.
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The Oort cloud is theorized to extend out as far as several light years, and a light year is a few thousand times the orbital radius of Neptune, or ~63,000x the orbit of Earth. At those distances the gravitational effects of the star will still be virtually uniform within the solar system, so any disruption should be incredibly small - it's the tidal disruptions of traveling through a varying gravitational field that wreak havoc. Consider: When Neptune is at it's closest to a hypothetical star 1 light ye
Re:What if... human's just weren't cut out for it? (Score:4, Interesting)
The end goal is survival.
Re: What if... human's just weren't cut out for it (Score:2)
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Mod up parent post please. This is the most insightful comment so far on this subject.
The idea the human kind is destined to colonize the universe is just remanant from protestantism and religious beliefs where God gave the universe to Adam to rule over it, etc. But, at the end, there is just no purpose for universe colonization once we have reached the point we are able to make the journey to a solar system distant from ours by three light-years. We would have reached the point we can sustain life into the
Re:What if... human's just weren't cut out for it? (Score:4, Interesting)
What was the point of colonizing anywhere? A small percentage of the population finds the potential of carving out a new life for themselves in a hostile, untamed environment more appealing than the life they could have where they are. Generally speaking I suspect they're not so much going towards something, as trying to escape the problems in their original home. Be that a shortage of food, uncomfortable population pressure, or oppressive leadership they lack the power to overthrow.
Keep in mind that our species has been the apex predator on the planet for probably 100,000 to 1,000,000 years, and still hasn't completely colonized the surface. That's a lot of generations where those individuals who hungered to colonize far-off places to populate new lands with their progeny - such wanderlust is likely encoded deep in our genes by now.
As for traveling 3 light years, I fail to see the problem. So it takes you a few decades or even centuries to cross between stars. So what? Assuming our civilization doesn't collapse in the next century or two we will likely have gotten a pretty good grip on maintaining small-scale closed ecosystems in space. LOTS of readily accessible resources right in our own solar system - plenty of new frontiers for the bold to make their fortunes or try to carve out a life free from oppression. And once we've mastered living in space indefinitely, then getting to another star is just a matter of wanting your independence more than you want to have close neighbors - well, that and gathering enough energy to survive the journey between stars. A generation ship may remove the need for speed, but you've still got to have enough power available keep the lights on for a very long journey.
As for humanity surviving on Earth - aside from a "grey-goo" scenario, or malevolent AI bent on human extermination, I can't think of anything that would actually present a credible threat to the species. Now lot's of things could bring about the collapse of our civilization, or even *almost* wipe out the species, but even a 99.9% extermination rate would leave 7+ million people - twice the population that is estimated to have existed before the birth of agriculture. Even a 99.9999% extermination rate would leave 7+ thousand people - more than the estimated population during the worst of the last major ice age. And those few survivors would have access to a wealth of knowledge and technology undreamed of by our ancestors - I doubt they'd have trouble eventually rebuilding a new civilization, at worst it might take a few thousand years - and we've been tool-makers for over a million already.
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As for humanity surviving on Earth - aside from a "grey-goo" scenario, or malevolent AI bent on human extermination, I can't think of anything that would actually present a credible threat to the species. Now lot's of things could bring about the collapse of our civilization, or even *almost* wipe out the species, but even a 99.9% extermination rate would leave 7+ million people - twice the population that is estimated to have existed before the birth of agriculture. Even a 99.9999% extermination rate would leave 7+ thousand people - more than the estimated population during the worst of the last major ice age. And those few survivors would have access to a wealth of knowledge and technology undreamed of by our ancestors - I doubt they'd have trouble eventually rebuilding a new civilization, at worst it might take a few thousand years - and we've been tool-makers for over a million already.
The biggest problem that people starting to rebuild civilisation after most of us have been wiped out - is going to be energy sources, then metals.
All of the easy to get to coal, oil and metals have been strip mined and basically used up - the really hard to get to stuff (which they won't be able to get to) is going to be all that remains.
The coal and oil could eventually be replenished, but only in geological timescales (and favourable conditions)
I suspect they'll be a stone-age people until a passin
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Somehow I suspect that any civilization capable of sustaining a presence in space for hundreds of thousands of years has probably harnessed at least fission, and probably fusion - either of which should be more than capable of providing power to a colony ship for a paltry few thousand years in interstellar space.
Now, moving an entire *civilization* is a different thing. In that case you might be better off considering taking your entire planet with you. A little stellar engineering a million years in adva
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But, at the end, there is just no purpose for universe colonization once we have reached the point we are able to make the journey to a solar system distant from ours by three light-years. We would have reached the point we can sustain life into the void without the Sun's energy for long periods of time and we are able to travel in mass on such a ship (required by the necessity of genetic diversity to survive as a spiece). What else is then needed?
Resources. Sustaining life for long periods of time without the Sun's energy merely requires a good energy storage system - for example, batteries that power a flashlight at night. At some point, you need fresh batteries - or fuel for your reactors, heavy metals for manufacturing, etc.
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I disagree. I believe this stems from an innate desire both to explore and to propagate our own kind. These are both powerful evolutionary drives, not something implanted into us via religion. I'm betting you can find plenty of atheists and agnostics who would like to see humankind survive and prosper out in the larger universe.
Whether you feel this is a good idea or not is largely a philosophical debate. The universe likely doesn't care one way or another. As such, my feeling is that we might as well
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Cultures are more useful than dead rocks. Even if interstellar trade in physical products turns out to be infeasible, the constant stream of exotic entertainment from neighboring systems would be well worth it.
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And point them where? The entire known universe is made of dead rocks, Anon. So either we wait for life to re-evolve elsewhere, or go colonize. And we've never been a patient lot.
Spaceships currently exist. Perhaps ones matching a given specification will one day, perhaps th
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As much as I believe there is value in manned space flight, I'm increasingly convinced that the real key to long term space flight is the ability to migrate human consciousness into machine form. It makes the ship less complex and solves a lot of problems with traveling long distances and some of the social and psychological side effects of relativistic effects.
First post? Really? (Score:2)
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)
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Instead of making the big lead from star to star. You can make smaller leaps from comet to comet.
This may best idea here as it may solve the replenishment of consumables such a long journey would entail. Hop from comet to comet until at the edge of the Oort cloud timing things so that the edge of another Oort cloud is passing by for the big interstellar hop to be made. H3 could be harvested on each comet for fusion energy to mine carbon, minerals and metals in preparation for the next hop. Any single hop w