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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.
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
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.
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.
I very much doubt that NASA's budgets will get any better over the next 450,000 years.
It won't; you must be thinking 250 - 470 million 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
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. Insignificant on goeolgical or evolutionary time scales, it's hundreds of times longer than our modern civilization has been around.
Dunno. I think a real spaceship might be more practical.
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 (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.
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.
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.
Pfft. Work smart, not hard.
250,000 to 470,000 years in the future...sounds about right.
The end goal is survival.
It little behooves the best of us to comment on the rest of us.
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.)
If you hurt anyone your reputation will be damaged and with it the ability to travel.
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.
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Is this the MPAA? Is this the RIAA? Is this the DMCA? I thought it was the USA!
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 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?
Achille Talon
Hop!
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
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.
--- Most topics have many sides worth arguing, allow me to take one opposite you.
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.
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.
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 advance and you can nudge that red dwarf into plunging right though your star system, allowing you to easily transfer any planets and other habitats to the new, far more navigable and essentially immortal star. You could then proceed to nudge your new star to skim other star systems for either colonization or to grab a few extra planets to decorate your new home
--- Most topics have many sides worth arguing, allow me to take one opposite you.
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.
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.
Minor quibble: if a Bussard ramjet can't be built, how can you salvage one?
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
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.
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.