The Fermi Paradox -- Where is everybody?

The idea that it's possible for Apollo level space technology to be used for interstellar flight is utterly laughable.

Gavinmad said:

The idea that it's possible for Apollo level space technology to be used for interstellar flight is utterly laughable.

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Who is making that assumption and why would that be relevant? I think the original problem takes into account that technology would improve. It was simply using the speed of light and how much %c we could achieve to come up with the 5-50 million number. Am I wrong about that?

pharmakos said:

No one was saying it would be a GOOD IDEA to use 1969 tech to travel to Alpha Centauri or anything, just that it wouldn't take that much time in a cosmic time scale. 50 million years was lazy expansion pretty much just put off til necessary every time. 5 million years was aggressive expansion.

Basically, the idea is that in the next few hundred years at the latest, we will probably be able to at the very least make probes that are self-replicating and designed to spread across the galaxy purely via automation. Once we make that technology, even if they for some bizarre reason it travelled at 1960s rocket speeds, it would only take a fraction of the age of the universe to saturate pretty fully

So if it would be that easy for a civilization to spread, how come we've seen no evidence that it's happened at all in the 14 billion year age of the universe? (Fermi Paradox restated to bring the conversation back home, I know you don't need to hear it again )

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That's what I was curious about if those estimates were accounting for improvements in tech along the way or making the claim simply using that static tech level.

You can still achieve relativistic speeds using our current Apollo level propulsion tech. Constant acceleration over a long period of time will always get you there... high school physics. The problem is the "long period of time" part of the equation. And braking. Go take a look at how fast Voyager 2 is moving right now, that thing was pretty much just using a couple cans of Whip It for propulsion and it's in interstellar space now.

I bet it's really killing Mudcrush Dirtfoot to not garbage all my and Khorum's posts in this thread.

It would only take 353 days of constant 1g acceleration to achieve 99.9999% of light speed. Hair and Hedman used the technology from 1969 for their paper because that was the most powerful extant chemical rocket known when they published. The idea being we could boost all the propellant to sustain 1g acceleration for as long as possible in orbit and assemble and fuel the seedships from there. Their conservative model capped it at 25% of c after a few months of acceleration and use gravity assist for another 50% of that base delta v. Remember that something like 80% of Voyager's current velocity is imparted by a series of gravity assist maneuvers around the jovian planets instead of the second stage booster.

A lot of people don't seem to get how constant acceleration makes things like the solar sail, Ion engines and low-propellant engines like the VASIMR exponentially faster than conventional chemical rockets. Think of it like compound interest---just a tiny increment every period builds into massive velocity over the whole mission. Constantly accelerating at 1g a vessel would only take 3 hours and 24 minutes to get from the Earth to the moon versus three days and four hours for the Apollos.

Merrith said:

Still my favorite thread on the board. Khorum the only part I'm skeptical on is the colonizing the galaxy in 50 million years with ~1969 tech. Is that assuming constant expansion and travel to go from one edge to the other basically on that rocket tech? Just feels like that ignores so many challenges that are unknown to us for interstellar travel, and the idea of just constantly expanding over that entire time period seems surprising to me. We've had that tech for 50 years, went to our closest other object (moon) a few times, then haven't actually sent a man even back that far in the last 47 years.

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Merrith said:

That's what I was curious about if those estimates were accounting for improvements in tech along the way or making the claim simply using that static tech level.

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Nah they used the 1969 figures because it was a mathematical paper published in a scientific journal. They didn't want to use speculative figures though that's absolutely a possiblity. This whole discussion started in the Astronomy thread so the study wasn't linked here but you can read the whole paper if you're still skeptical:


Their conclusion, after running 250 iterations of their simulation was:

Conclusion

In 250 iterations a civilization with the highest proclivity to emigrate (c=1) will travel approximately 500 light years, about half the distance possible, although the results vary somewhat from graph to graph. This rate of expansion is approximately one-fourth of the maximum travel speed of Spatial dispersion of interstellar civilizations. At this modest rate, a civilization could still span the Milky Way in less than 50 Myr. Higher travel speeds could obviously reduce this number, so the first explanation of Fermi’s paradox (Gros 2005) is not supported by the model presented. The model shows that in the 5 Gyr the Universe has been able to support intelligent life, the first civilization to emerge could have colonized the Galaxy 100 times over and done it long before the second civilization even evolved (Hair 2011).

Without speculating about things that are currently deemed impossible (wormhole travel, warp drives) they showed that with the best technology humanity has achieved so far, any given civilization would have colonized the whole galaxy 100 times via seed ships creating daughter colonies who would themselves eventually send out colonies themselves. It's essentially the sigmoid curve of an exponential growth function.

Ships that somehow magically power themselves and carry enough supplies for their crews on these incredibly long journeys while also carrying enough fuel for the long periods of acceleration and deceleration?

khorum said:

It's essentially the sigmoid curve of an exponential growth function.

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As long as we're slinging out as many semi-technical words as possible, we may as well be careful and precise. Exponential growth functions are not sigmoidal. (Your linked paper's results are exponential.) A typical sigmoid function used in growth modeling would be logistic.

ZyyzYzzy said:

Magnets

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But how do they work?

Gavinmad said:

Ships that somehow magically power themselves and carry enough supplies for their crews on these incredibly long journeys while also carrying enough fuel for the long periods of acceleration and deceleration?

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Why would you send crew and supplies? That might've been a consideration but it wouldn't be the most efficient payload for a seedship. At most it would be MAYBE frozen embryos and a hold full of robots to pop them out and raise/train/educate them in orbit while robots built their habitat on the surface.

Even when you factor in a good 2000 years of butthurt colonists, tribalism, warfare, dark ages, renaissance, and re-industrialization before the daughter colonies were able to send seedships out of their own, that's STILL barely a blip on the cosmic timetable and it would still put the total expansion at around 25 million years. I'm sure 50 million year figure accounts for the occasional galactic war and waves of genocide.

Gavinmad said:

Ships that somehow magically power themselves and carry enough supplies for their crews on these incredibly long journeys while also carrying enough fuel for the long periods of acceleration and deceleration?

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You mean like...submarines? Even easier if you are taking out the need for human life support on the journey.

Obviously interstellar travel is far more technical, difficult, or whatever adjective you want to use. But it's by no means so far out of reach as to be "magical".

Politics has had a far greater negative effect on our progress in space than technology.

TheBeagle said:

You mean like...submarines? Even easier if you are taking out the need for human life support on the journey.

Obviously interstellar travel is far more technical, difficult, or whatever adjective you want to use. But it's by no means so far out of reach as to be "magical".

Politics has had a far greater negative effect on our progress in space than technology.

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Again it only SEEMS out of reach because our brains think in terms of our 83-year average lifespan. To a gnat travelling from New York to LA is beyond the scope of reality because they'll be dead in a couple days, but they sure as hell have the speed to do it if they didn't.

We WALKED from New York to LA because we could.

khorum said:

Again it only SEEMS out of reach because our brains think in terms of our 83-year average lifespan. To a gnat travelling from New York to LA is beyond the scope of reality because they'll be dead in a couple days, but they sure as hell have the speed to do it if they didn't.

We WALKED from New York to LA because we could.

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If humans were a eusocial species like ants, bees, and wasps and still retained our ability to innovate we would be setting up jump stations around Jupiter right now instead of arguing about feminine penises.

khorum said:

Again it only SEEMS out of reach

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The frustrating thing is you're right, and it's really not out of reach. The only reason we're not on Mars and other bodies now is because we collectively don't want to. I get really sad thinking about where we could be as a species if we'd spent the years since Apollo focused on exploration instead of shooting each other and arguing over which particular moldy book should tell us who and how to fuck.

I've got a cousin who works at SpaceX (best factory tour ever), and from that view it seems there's really no reason we can't do everything Musk is working towards in short order. A relatively pitifully small amount of money is the barrier between us and huge progress.

TheBeagle said:

If humans were a eusocial species like ants, bees, and wasps and still retained our ability to innovate we would be setting up jump stations around Jupiter right now instead of arguing about feminine penises.

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That's just extra narrow anthropomorphism. It's also fun and entertaining to imagine your CURRENT circumstances extending infinitely into the future when in fact that just describes...well...your current circumstances.

Just 50 years ago we achieved the means that would allow our species to colonize the entire Milky Way galaxy! But everyone watching Armstrong land on the Moon were just fist-bumping over dicking the Russians down out of the space race for good.

Despite the current zeitgeist, you have to think in terms of the whole species. There are people on this planet right now who are as disciplined and organized as ants and bees and if they were in charge of everything we would have hentai sexbots colonizing Titan as we speak. But they're not in charge, instead the folks who are busy squabbling over girldicks are.

But that's as frivolous and impermanent as you and me. Our species, however, like all other species, will REACH OUT for every possible avenue for survival once our circumstances require it. It would be nicer if we didn't need necessity to do it, but it almost always does.

Yep. It just sucks that, because of our own mortality, those of us that actually care the most about this stuff won't be able to see it come to fruition. Instead we have to watch our inheritance be squandered to pay for 400lb Mexican trannies get their dicks chopped.

Pass on your genes faggots and maybe they can see it.

That's just because we'll be dead in about 40 years though. Remember Hair/Hedman's figure that any species with the technology we developed in 1969 could have colonized the galaxy?

We speciated from some homo erectus less than 460,000 years ago. So say it takes evolution 461,969 years to go from the monkeys in Kubrick's 2001 to landing on the moon, then let's be generous and say it takes another 48,000 to finally resolve our global dickgirls crisis and it takes humans a straight 500,000 years to go from evolving sapience to colonizing the galaxy. That's barely even a blip in geologic time, it's inconsequential in cosmic timescales.

If it takes us 5 million years to finish colonizing everything, TEN HUMAN-LEVEL SPECIES could have popped out of their parent species to become spacefarers.

TheBeagle said:

You can still achieve relativistic speeds using our current Apollo level propulsion tech. Constant acceleration over a long period of time will always get you there... high school physics. The problem is the "long period of time" part of the equation. And braking. Go take a look at how fast Voyager 2 is moving right now, that thing was pretty much just using a couple cans of Whip It for propulsion and it's in interstellar space now.

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It depends what % of c we're talking about. Below 0.9c or so yes, time and slowing down are the biggest problems AFTER the possibility of running into almost anything larger than a rock. If you want to start traveling much greater than 0.9c or so, that's where mass (and thus energy) start to increase in a way that makes traveling at these velocities seem nigh impossible because at some point dust particles carry the energy of bombs.

But actually time isn't even as big of an issue for the travelers themselves. Let's not forget that if you can get up to some decent fraction of c, time will start to slow down for you, and space actually shrinks. If you make a journey to a star 20 light years away with an average speed of 0.5c, it doesn't take you 40 years to get there according to your own clocks, its less.