Slashdot Mirror
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.
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
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.
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.
---
Is this the MPAA? Is this the RIAA? Is this the DMCA? I thought it was the USA!
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.
Warning: Opinions known to be heavily biased.
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.
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.
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.