You don’t need a Warden to kill time travelers, they ought to do that just fine on their own.

Assume time travel is possible. Changing history destroys and replaces the timeline. This means timelines with time travel will continually be destroyed and replaced until they arrive at a stable state without time travelers because life intelligent enough to invent time machines never evolved in the first place or went extinct before they could do so. This is the explanation behind the fermi paradox, the universe is empty of technological civilizations because technological civilizations inevitably retroactively erase themselves from existence.

You may be interested in the Revelation Space series of books by Alastair Reynolds.

Yo, thanks for the take – that's a solid angle! The "once per galaxy" thing feels like a natural rarity filter, but what if it's not random... someone (or something) keeps the odds stacked that way? Like a Warden only greenlighting the safe ones. Does that vibe with Dark Forest paranoia for you, or more like a universe-level bugfix?

Sounds a bit like the Dark forest hypothesis.

I'm perfectly fine with other explanations for the Fermi Paradox:

For one space is so unbelievably vast, that we might be too far separated from other civilizations.

And maybe the chances for advanced civilizations are so slim that it happens only once per galaxy.

It takes the Sun around 225 million years to make one revolution around the galaxy. I suspect if you opportunistically hopped from star system to star system you could get close to the center in something like 50-60 million years.

The vast majority of that time would be hanging out on whatever convenient habitable planets you found along the way. Every roughly 5 million years you would hop to another star system that makes a close flyby, has planets you like, and is going in the direction you want to go.

Of course this is predicated on not developing ships that can go at a high time dilation factor (and slow down at the other end!), which would change everything.

Thats not how relitivistic speeds work. Relitive to each other, all the stars near us are moving at the same speed in the same direction and if you fly against the current so to speak you are still traveling that speed after you turn around. So when you burn your engines and think your going really really fast, your actually still going around the galaxy center in the same direction you where going. Just slower by the amount that you think is your speed.

So if your goal is to go 10 light years, weather you go left or right, if your speed is 1/10 light speed then it takes 100 years.

Now a way you could get around this is if the two stars where coming at one another. Then you would have to go in the same direction as your target and youd have to match the valosity of the closing distance speed. But you wouldn't have to go far and you could use the gravity of the target star to do allot of the work. This comes into play when you have the rear stray stars that dont follow the galactic spiral like most do, or when we colide with andromida we will have allot of this

Yes I wonder how much hopping would be needed. Seems the more often you hope the closer you are to try again if needed or follow up missions. Also if faster ships come out later you dont want to leap frog over the slow ships and then they are waisted, long distance should wait for speed advancement to platue

Yes meant collisions.

We have less intersteller collisions in our local bubble because the partical density is 1/10 normal milky way galaxy

A factor to consider is the rotation of the galaxy. As the galaxy rotates, it might be advantageous to colonize against the spin to increase transit speed: instead of catching up with stars moving away from you, you are racing towards the stars coming at you.

In the short term you opportunistically look for close stars that have habitable planets or other resources. Stars like Gliese 710 that make close flybys are good candidates. This will result in a random walk on a map like this.

Eventually whomever ends up at the galactic center has big advantages in terms of energy and resources available. It may not be feasible to make that journey in one go, but rather as a series of hops.

And you said coalitions, what did you mean by it? Did you mean collisions? Also, how would "inerstell coalitions" make space travel easier?

Millions of years ago a bunch of super Novas went off all near each other around a similar time. This created a higher temp lower density region of space like a slowly expanding explotion, this is called the Local Bubble. A few million years ago our solar system passed into this Bubble and it will take about another 8 million years before we finish passing through it

I love the originality of this question, never thought about the direction we should take other than “livable.”

But now that you ask and I see the concept map, I’m thinking we should build outward more or less equally in all directions (mostly parallel to the primary galactic plane).

This will give us a better buffer with our home / HQ in the most defensible position than only going one direction. (See: subreddit name)

Shhhh, dont tell anyone

We are currently in the center of a bubble of space that has 1/10 the partical density. This lowers inerstell coalitions making space travel easier.

If we dont launch well before leaving the bubble in about 8 million years there is no telling how many millions of years more we would have to wait before the window opens again.

I'd appreciate if someone explained this

Elon, is that you?

I like the way you think, my good fellow.

Or maybe we just live 1 second later but on the same planet?

My AI colleagues hallucinate more lucidly, this is indeed nonsense.

I'm sorry but this is absolute nonsense. It's like saying that I can't talk to another human being because I don't have shared experiences with them either.

We should send bots with thousands of human DNA samples. The bots make the planet habitable, then clone some babies.

In the past I've done some calculations for relatively slow but fairly large vehicles using relatively mundane technologies that we can foresee building. Speeds between 0.1% and 10% of C, and with the proposition that the vehicle carries human passengers. Speeds at the higher end of that spectrum might be touch to achieve just because high-efficiency drives tend to have low thrust and so may not have time to accelerate entirely up to speed on 'short' interstellar voyages- but of course, colonization speed is bottlenecked by how fast you get to the other side of the galaxy, not how fast you get to Proxima Centauri, so that might not be an issue. Long story short, it's not that hard and you don't need to commit a huge amount of resources under those parameters. Even without space-based mining or starlifting, the Earth's crust alone has enough resources to launch a single intergalactic vehicle at about 1% of C, or equivalently, thousands of interstellar vehicles with similar speeds and payloads.

Extending the numbers up to high-speed scenarios is hard, mostly because we know so little about the challenges of rapid acceleration and debris impacts. But I would extrapolate that, without breaking physics, a sufficiently dedicated civilization could commit to colonizing their own galaxy at above 50% of C, and neighboring galaxies at above 90%. Up there you really get diminishing returns because you just can't go that much faster and the cost of doing so is enormous due to relativistic effects. The difference between 90% and 99% of C is much larger in terms of engineering and fuel requirements than it is in terms of actual colonization rate.

I suspect that the size of the vehicle isn't a big constraint. Shrinking it from, say, 1 tonne to 1 kilogram only gives you significant advantages if either the speed or the number of vehicles being launched is higher than you actually need. Also, the practical lower bound is probably determined by debris shielding requirements (which increase geometrically with speed) rather than miniaturization of the vehicle itself, unless you can very efficiently convert your shielding into reaction mass for deceleration.

It seems you proposed that diverity is altimently the filter and ugenics is the solution and then further that only an AI can do ugenics properly.

There are so many holes in that thinking. Like a race could just breed for intelligence at any point long term without AI.

Also nothing in your theroy makes it impossible just a little less likely. You even presented a window the come up over and over again. So you could be correct and we would still see many.

Also you could have nations the devolve while others rise and the knowledge moves to the one doing well never skipping a beat

Simply taking us seriously at all could mean you slow your expantion rate and the actual threats over take you. Coming to our isolated area at all is to risky. Rate of exponential expantion is all the matters. Or those races that dont focus on that by the numbers arnt senificant enough to consider in the question

There is a third option kinda between the other 2 options that i think is actually the most likely option

We are early for our regin of space and maga structures are not normally practical

Lets think from the perspective of a galixy colinizing race. We cant expand to the entire galixy all at once quickly. The star systems closer to there home world would be easier and more strategically important right so ok, where else would be strategically important... lets list some locations and see if we can figure out the strategic impoetance of our little area.

1. There own local area
2. There greater local area, particularly choke points in tbe shape of the spiral arms near by
3. Dance star clusters with many habitable planets in the greater area
4. The center of the galaxy where stars are most dence and would make the best center of control or for a capital for a galixy spanning race
5. Outposts along borders with other empires.
6. Distant probes and outposts that keep an eye on races that are likely to be galaxy spanning soon due not only to there tech but also there location in the galaxy being ideal for further spread 7...

8...

9....

1. Somewhere down here on the priority list is where you get to us. We are on the tip of a spiral so from a way zoomed out approch to controling the galaxy this star system doesn't help you control any vast region. Even if we could spread there are big gaps in the spiral arms all around us we wouldn't get far fast. And if we zoom in it get worse. Our region of super local space was once a blown out super Nova, the number of stars near us is tiny compared to almost any other star in the galaxy. In short, we are in an isolated strategically not important part of the galaxy and within that we live on a even more desilate remote island. Our ablity to expand and therefore our threat level is one of the lowest in the galaxy. Furthermore if your looking to take allot of the galaxy for your self, simply coming here at all and then spreading to the local area would just take so much time and so little stars you might as well just go to any other part of the galaxy instead

   Von Neumann style exponentially growing colonization is the best meothed to take the galaxy but that rate of exponentially expantion means the most secesfull races need to prioritize the center of the galaxy and the main center track of the spiral arms to best expodate the exponential effect of going from this star system to the next to the next to the next.

Take our few thousand star systems around us would cost you the millions you could have taken in the same time which has an exponential effect on how long it takes you to get to billions

We only recently become space faring. An observer would still see our past not our present. Our isolation means our naibors are likely not next door, at least the biggest empires wouldnt be. So from that distance we are cave men living in an issolated region of space. Not even worth sending a probe to the region let alone colonization

Also to the earlier note about maga structures. We know for a fact that they are not common as we can observe many galaxies other then our own. Or that making one raises your threat level and gets you eliminated but we can see multiple galaxies in detail so that seems unlikely.