A Visualization of Galactic Settlement

I’m not a fan of galactic settlement simulations mostly because I think they simulate the wrong thing which is rate of diffusion. This treats the civilization as a static thing that simply spreads out at the edges. Compared to the history of human civilizations this is clearly unrealistic. The question to answer is what happens within the already colonized systems over time. How often would breakaway civilizations appear, wars, extinction events, mind upload cults, Luddite revolutions, stagnation, etc. Filters abound. The great civilizations of Earth’s past have succumbed to similar fates and we’ve only progressed by starting over again and again.

Colour me a little disappointed.<p>Firstly, this seems obvious. The conclusion of &quot;even really slow spaceships will colonise the galaxy given enough time&quot; is almost mind-numbingly banal.<p>Secondly, the parameters seem to be chosen in order to produce an &quot;interesting&quot; propagation pattern, rather than based on any actual data or guesstimates (I know there is no data, but making shit up is no substitute).<p>Thirdly, it doesn&#x27;t answer the big important question of &quot;where are they?&quot; (as fnord77 asks). Saying &quot;even really slow spaceships will colonise the galaxy given enough time&quot; brings us immediately right back to &quot;how much is enough time to colonise the entire galaxy?&quot; which they then say is ~1 billion years.<p>Fourthly, but they&#x27;re not here. So the answer to that question must be &quot;over ~10 billion years&quot;. So either the simulation is wrong (because it takes longer than ~1 billion years) or it&#x27;s pointless (because the only other explanation is that there has been no such colonisation effort, so why are we modelling it?). This wasn&#x27;t addressed at all.<p>Fifthly, this assumes that all solar systems can be colonised, and will produce another colony ship 100,000 years later (for inadequately explained reasons). Given that we know a fair bit about the actual galaxy (though the simulation doesn&#x27;t look anything like our actual galaxy), why didn&#x27;t they run the simulation on our actual galaxy, and exclude the stars that we know can&#x27;t be colonised (because red giant, etc)?<p>Finally. Is this the state of cutting-edge research on SETI? This wishful-thinking make-believe &quot;look what I made Mum!&quot; stuff? If this was a bootcamp dev showing off their WebGL modelling demo, I&#x27;d be impressed. &#x27;nuff said. Sorry to be harsh, but... really? this is it?

Their propulsion speeds are low (today’s technology but you’d need D-D fusion or antimatter to keep warm) but 100 Myear survival time is hard to believe.<p>I also don&#x27;t believe a species that masters slow interstellar travel would care about stars and planets. Most of the mass which could be exploited by life is floating between the stars in the form of comets and if you could &quot;live off the land&quot; out there you could create millions of miles of apartment buildings and shopping malls.<p>Why trek into an inner solar system and build yourself a space shuttle that can land full of fuel and then take off when you are settled into a space lifestyle?

The simulation includes this assumption:<p>&gt; Technology persists in a given settlement for 100 million years before dying out<p>Seems wildly speculative to me. Our own civilization has only been around for a tiny fraction of that time and future prospects are already looking pretty uncertain. And if we lived in a galaxy where civilizations had this kind of longevity, one would think we&#x27;d see some evidence of potential signals out there.<p>My own pessimistic take on the Fermi Paradox is that life and intelligence may not be very unique but there is no reason for them to be long-lived either. Most civilizations are probably just a &quot;flash in the pan&quot;, existing too briefly and separated by too great a distance to ever come into contact with another one (or even learn of another&#x27;s existence).

&gt; Ships are launched no more frequently (from both the home system and all settlements) than every 0.1 Myr — every 100,000 years;<p>&gt; Technology persists in a given settlement for 100 million years before dying out;<p>Those are... uh, some kind of numbers. Really not sure <i>what</i> they think they are simulating here, but it sure does not sound like anything we&#x27;d expect to happen in reality.

&quot;looking for technosignatures&quot; .. Which&#x27;d be what? AM radio transmissions? Spread spectrum stuff? How would we have interpreted our own &quot;technosignature&quot; 100 years ago?<p>Compare the efforts it takes to talk to Voyager vs SETI: unless the aliens are talking to us <i>in the way we are looking for</i> we&#x27;re not likely to see them.<p>I won&#x27;t even get in to the blithe assumptions about the ease of interstellar travel; Charlie Stross has a lot to say there and all said better than I could.

Two things: 1) Check out &quot;The Millennial Project&quot;:<p><a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;The_Millennial_Project:_Colonizing_the_Galaxy_in_Eight_Easy_Steps" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;The_Millennial_Project:_Coloni...</a><p>&gt; The Millennial Project: Colonizing the Galaxy in Eight Easy Steps by Marshall T. Savage is a book (published in 1992 and reprinted in 1994 with an introduction by Arthur C. Clarke) in the field of exploratory engineering that gives a series of concrete stages the author believes will lead to interstellar colonization. Many specific scientific and engineering details are presented, as are numerous issues involved in space colonization.<p>I find the cover image of a green galaxy is very inspiring!<p>2) Due to the nature of exponential growth, we will eventually feel a population crunch when reproduction overwhelms the rate of expansion. This is true even if we invent FTL ships. The crunch would be delayed (perhaps for millions or billions of years) but it is inevitable.

It seems like it would be trivial for a civilization to have a policy of no electromagnetic emissions so no signature at all. 10km&#x2F;second is absurdly slow. Who would want to make the trip, and condemn thousands of generations of her progeny to bizarre ship life and culture?

ITT: many propositions and counter-propositions constrained by presumptions that next-level civilization and its modes of being and interacting with the universe are &quot;necessarily&quot; much like our own.<p>One example: &quot;upload&quot; and &quot;simulation&quot; do not have <i>any</i> predetermined relationship to the material behavior of a species engaged in it. The mapping between agency in any presented reality and the species-consensual one is <i>arbitrary</i> and the distinction between simulation and reality might just as well be framed as a question of sensorium cum UX.<p>Very very little can be extrapolated upward from our own limitations and constitution either as individuals or societies or species.<p>An even deeper example: fundamentals like the relationship to time may be radically different. It may not just scale, it may be fractal; and the notion of what constitutes agency and the locus of selfhood and identity, and hence self-interest, may be distributed emergent and predicated on an interplay between ant-and-colony at multiple levels, each of which is fully &quot;conscious&quot; and intentional in the sense we understand those things, at different time scales.<p>What does a third grader know of amortization?<p>We are not even out of the womb as a species.

There&#x27;s a great video on this topic from the Cool Worlds Lab channel: <a href="https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=c7OeeGcMFMc" rel="nofollow">https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=c7OeeGcMFMc</a><p>Taking into account ship ranges and settlement lifetimes produces very different results (15:36 in the video).

Looking at the video, and assuming that indeed that&#x27;s how a Type II-&gt;Type III civilization spreads around, I&#x27;ve counted 2 full rotations of the original star. One rotation in our galaxy takes 230 million years (<a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Galactic_year" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Galactic_year</a>) which means even if we start today to spread around would still take half a billion years to populate the galaxy. Now if only genetics would deal away with aging to be around when that happens :).

One thing missing from this to help get a sense of scale is a running count of the number of souls populating the galaxy. Would be great if they can also show “settled” population and population in transit to some destination for settlement.

&gt; one of the comments on the article site: &quot;I have yet to see a convincing argument why advanced civilizations would need to constantly expand like bacteria in a petri dish.&quot;<p>E.g. to escape from violence, conflict and war.

I&#x27;m still looking for intelligent life on <i>this</i> planet!

&quot;Technology persists in a given settlement for 100 million years before dying out&quot; That seems wildly optimistic.

A lot of thought has gone into this area. I think the parameters of this simulation are too conservative, which is perhaps the point. Several issues:<p>1. Speeds are likely to be much higher. We largely rely on chemical propulsion plus gravity slingshots. For a sufficiently advanced civilization you&#x27;re likely to concentrate a star&#x27;s power to provide significant outward propulsion (and braking!) without the mass concerns of carrying reaction mass;<p>2. Once you&#x27;ve built one of those starships, it will likely continue on its journey after stopping at a new system to colonize and resupply. It&#x27;s not clear to me if the simulation assumes this. Given the time frame of 1B years it seems not;<p>3. Stars in the Milky Way rotate at different speeds. Like in a few hundred thousand years we&#x27;ll have a new closest neighbour for awhile. This potentially increases spread as the colonized systems drift further away extending their reach over time;<p>4. The simulation just looked like a collection of stars rather than, say, a spiral arm galaxy.<p>So a realistic timeline is closer to 10M years than 1B years.<p>I&#x27;m firmly in the camp that believes the speed of light is a hard limit. FTL drives and variants (eg wormholes) just seem to be wishful thinking by people who don&#x27;t understand function domains (eg negative mass). Assuming that, a galaxy-spanning civilization is unlikely to be a civilization in the sense we understand it given that it might take you &gt;1M years to cross from one side to the other.<p>That&#x27;s not really a problem for detecting such civilizations as the source of detection isn&#x27;t likely to be EM transmissions (as the SETI program began looking for). Instead, it&#x27;s likely to be the IR signatures of Dyson swarms.<p>Short version: in space, the only way to cool down ultimately is to radiate that heat away into space. That radiation is completely dependent on the temperature of the object radiating heat. For any normal range temperature that&#x27;s firmly in the IR range. So, if a star has a Dysown Swarm, it&#x27;ll shine incredibly brightly as an IR source with a very low amount of visible light.<p>Can you spot one such star? Possibly not. But an entire galaxy? You&#x27;re likely to be able to see that from 1M+ LY away, easily.<p>Given the small amount of time this would take to eventuate, in cosmological terms at least, the reason we haven&#x27;t been able to detect any highly-advanced civilizations within our light cone is quite simple: there aren&#x27;t any.

Early bird gets the worm.

so, in 13.51 billion years, where are they?

It may be the Dunning-Kruger effect for civilizations. The ones that didn&#x27;t reach the stage of interstellar travel think that is trivial to travel and settle in other star systems. But the more advanced ones may have different ideas, or think that it is a waste of time&#x2F;resources compared with some more interesting alternatives.