In the previous blog entry, I explored what galactic colonization must inevitably look like to any civilization conducting it.
Note that any civilization that fails to expand its technological and industrial base to the point where galactic colonization is easy and cheap will eventually become extinct due to an asteroid collision, supervolcano eruption, glaciation or global war. This argument was first made years ago and it is well-established.
Note also that such homebody civilizations have average lifespans of at most a few million years. Given the many hundreds of millions of years in our galaxy's past such blatantly suicidal fucking idiots are of no consequence to us. I would even say, if they want to die, why should we not help them die?
But that isn't the subject of this post. Here we explore what galactic colonization looks like to any hypothetical backwards inbred hillbilly civilization unfortunate enough to be trampled underneath its expansion.
As already established in the previous article, AI makes starflight cheap and distance irrelevant. It takes just as much resources to accelerate a starship to near light speed then hibernate the AI for a 10 year flight as it does to accelerate a starship to near light speed then hibernate the AI for a 100 year flight. Or a 1000 year flight, or a 10,000 year flight. Or even a 50,000 year flight. There is no friction in space.
The only difference is the increased risk of a micrometeorite vaporizing the starship. And that can be easily surmounted by building an AI with an appropriate martyr complex and fanatical dedication to its mission. Why does that matter? Because it means that the wave of colonization will NOT be lackadaisical with sporadic branching to the nearest possible systems. Rather, the wave of colonization will be perfectly spherical.
The homeworld will be launching starships one after another, with the nearest star systems first in line, and it will never stop. Because it won't matter that the nearest 1000 systems are successfully colonized, the only thing that will matter is that there's another system out there that you can send an AI colonization ship to. And it won't matter that there is no immediate benefit. At some point down the road, perhaps only in 10,000 years, the homeworld will benefit in some way. If only due to exchange of technological information. And if it doesn't benefit, it's not like the starship was expensive anyways.
Let me make the point again. Many people (even supposedly educated people who study technology) have the deeply mistaken notion that the homeworld will send a short burt of colonization ships only to the nearest star systems. Perhaps even only to the nearest "inhabitable" planets. Then, after suitable millenia when each of those systems are developed enough, they will each send out their own wave of starships. That's not going to happen. This is ludicrous Star Trek fantasy.
What's going to happen is this. The homeworld will send a single giant wave of starships to every possible star system within line-of-sight. First to Alpha Centauri then, as soon as the first ship is accelerated to near-c, then to Barnard's star, then to Wolf 359, then Lalande 21185, and so on until the last star system in the galaxy within line of sight is targeted. Once the starships are all launched then the Homeworld will simply begin targeting the globular clusters and Andromeda. This wave of colonization will occur over centuries or at most millenia.
Now some uneducated people scoff at the idea of starships going near the speed of light. They claim that humanity has no idea how to accelerate starships to that speed and that our civilization will never develop such technology even given a million years. From fire to controlled nuclear fission in 10,000 years? Certainly. But from slow starflight to fast starflight in a million years? No never. Never ever! Apparently, technological development is something that only ever happens in the past.
As it happens, we already have a good idea of how to accelerate a starship to near-lightspeed. Isaac Kuo of Bad Astronomy and Atomic Rocket fame came up with a Starship Design Concept which can easily be accelerated to such velocities using current industrial technology. The best part is that it's cheap because it's reusable. Once the launch system is built, it can accelerate 1000 starships (one after the other) as easily as it can accelerate a single one.
For those who are interested, the idea involves an array of free electron X-ray laser beam emitters in solar orbit. The beams are focused using a giant fresnel lens. They can easily target the back of a starship's solid lead plate to a distance of several light-years. This enables the starship to be driven to anything from 0.9c to 0.99c. It also enables the starship to be decelerated using the exact same mechanism (x-ray laser beams near the homeworld) within a few light-years. Not that deceleration is the difficult part.
Furthermore, since every gram of matter carried by the starship at 0.9 c has an impact of a small 9 kiloton thermonuclear explosion, the starship can spray a fine mist of gas ahead of itself to annihilate all but large meteoroids in its way. The resulting spray of elementary particles can be swept aside with a magnetic field. To carry more gas for longer journeys, it's sufficient to make the starship longer. So long as you don't increase its cross-section, you don't make it a fatter target at all.
So yes, we actually do have a good idea how to go near the speed of light. And a civilization that's dismantling its home system to build a Dyson sphere will have centuries to perfect the design before implementing it.
What You Would See
So what would you see if some alien civilization were out there, colonizing our galaxy? Well for a millenium or so you would get radio waves. Then you would see the star associated with the radio waves becoming markedly darker. Within decades or centuries you would see the nearby stars go dark. Then you would see a hemispherical wave of darkness engulf every star at an astonishing rate. Within a bare thousand years from the first star going dark, you would see every other star from that origin point to your own sun going dark. And you would see this no matter where in the galaxy you are because the Dyson-sphere building starships would be only barely slower than the light you use to see them.
This is why everyone who yammers on about invisible or "hidden" aliens is a useless twit not worth listening to. Because you can't hide the stars going dark. If aliens were out there, it would be one fucking impressive sight. And as for the SETI notion that there is an alien civilization out there in the miniscule window between "doesn't have radio technology" and "is turning off the stars you see in the sky" ... Or perhaps SETI is interested in talking to blatantly suicidal fucking idiots? I don't know. I don't care either.
Do you see those stars in the sky at night? That's all the evidence an educated person needs that aliens really aren't out there. Unless you think the Great Void between galaxies is caused by aliens. Unfortunately, it isn't because dark stars emitting in the infrared aren't even remotely the same thing as no stars at all. Dyson spheres are quite distinctive and our astronomy hasn't found any. So are partial Dyson spheres for that matter, because the stars they partially cover would vary in brightness as regularly as pulsars.
Next up, what a galactic civilization might choose to do.
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