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You can make a fairly strong statistical argument there are no spacefaring species in our galaxy. Even at 1% the speed of light a species could fully colonize t

You can make a fairly strong statistical argument there are no spacefaring species in our galaxy. Even at 1% the speed of light a species could fully colonize the galaxy in 10 million years, 0.1% the age of the universe. That we see nothing implies intellgent life is rare, short lived, or we're early in the age of the universe. For example, red dwarfs will last trillions of years compared to the sun's 5B lifespan.

Retric 3y ago
1% the speed of light is stupidly fast to colonize a galaxy. It only sounds reasonable in the same way startup claim if we can just capture 1% of the X market, while forgetting numbers much smaller exist. Let’s assume super tech they can build that somehow allows vastly faster speeds than we can today ~120 km/s worth of DeltaV. Half that is spent slowing down so we’re talking 0.02% c. Now let’s assume half the time is spent in flight and half the time is spent colonizing stars before launching ships. So now we’re down to 0.01% C. Suddenly 1 Billion years is a more reasonable estimate and even that takes super tech we don’t have any idea how to build and assumes nothing fails. Several more advanced civilizations could be colonizing the galaxy today that are still 10 billion years from finishing.
- DennisP 3y ago
  Fusion rockets would be able to get over 1% c. I think the theoretical maximum for fusion is around 10%.
  - Retric 3y ago
    Fusion rockets might be able to get a sufficiently large spacecraft over 1% c. If you’re instead sending multiple generations of craft and waiting until each succeeds then it’s 1/n %c etc. Colonization using a massive habitat capable of extreme redundancy and asteroid mining could be a completely viable solution to colonization. But such a structure wouldn’t be light. Hitting 1% c could very well take megastructures that a civilization would rather spend on redundant craft etc. We can dream, but we’re nowhere close to being able to say what’s actually viable.
Intralexical 3y ago
> That we see nothing implies intellgent life is rare, short lived, or we're early in the age of the universe. Or it implies that not everybody's first instinct on seeing a vast galaxy is to try to take it over ASAP. If you want resources for quality of life— Gas giants are a thing. If you're an explorer driven by curiosity, then take only samples, leave only memories, right. If you want money— Century-long shipping times with civilization-scaled fuel costs tend to eat into profit margins. If you're worried about survival— genuinely worried about survival, on a level personal enough to motivate action, not just academically or for fun— then the focus is on people you know and care about; all of those are here. In fact, I suspect the ones that see other stars and immediately think "Mine mine all mine!" probably have a higher chance of nuking themselves before they even get out of their star system.
- perilunar 3y ago
  > That we see nothing implies intellgent life is rare, short lived, or we're early in the age of the universe. > > Or it implies that not everybody's first instinct on seeing a vast galaxy is to try to take it over ASAP. Or it may simply imply that intelligent life is good at hiding and does not want to be seen e.g. the dark forest hypothesis.
  - kuchenbecker 3y ago
    Dark forest hypothesis uses lack of evidence as evidence. There is little to back the claim the galaxy is full, BUT if it is full then the Dark Forest could be a reason we haven't detected.
jvmboi 3y ago
If the universe is Einsteinian, I don't think "colonizing" the stars is a thing that makes sense. We might do it once because we are sentimental like that but maybe that's owed to unique psychology owed to unique circumstances on earth. I don't see how you could rationally justify spending this stupefying amount of resources on sending people into the void where, even if all goes well, you can barely talk to them, have no trade and no social contact with them at all.` Basically you are paying to split off a one-way branch of the species. Just consider that if we could colonize Alpha Centauri that means that each message has a 8 year or 1/10 of a human life span roundtrip. What would you even talk about with that kind of latency?
- pie420 3y ago
  Very shortminded and proto-humancentric thinking. This is all done via AI and automated factories that terraform planets into Von Neumann manufacturing hubs, which then each send millions/billions of Von Neumann's out into the galaxy, each Von Neumann probe containing the tech/machinery to terraform another planet into another Dyson Sphere manufacturing hub. If you're really sentimental about humanity, you can include human DNA on the von neumann probess, and while the von neumann probe is terraforming a new planet, it can also grow humans in vitro. Why would we (or our AI overlords) want to spread through the galaxy like this? Why does cancer spread through it's host? Why did europeans colonize the entire earth? Life is a virus that spreads without limit. "I don't see how you could rationally justify spending this stupefying amount of resources on sending people into the void where, even if all goes well, you can barely talk to them, have no trade and no social contact with them at all." Do you not understand why people invested in early merchant ships in like the 1500s? You spend a lot on a ship, send the ship to trade, and they come back with spice, that you sell at a profit, buy more ships, rinse and repeat. Same here: spend a couple quadrillion dollars, send off some von neumann probes, wait 50 million years, and then see if you've colonized a small cluster of the galaxy, or if your von neumann probe fleet was destroyed by a gamma ray burst or an uncharted supermassive black hole.
  - Retric 3y ago
    An immortal might justify sending automated probes to the nearest few systems to eventually collect resources and send them back to you. But collecting resources from 10,000+ light years away just doesn’t make sense. By that point you have long since turned the local star system into a black hole via excess mass.

Retric 3y ago

1% the speed of light is stupidly fast to colonize a galaxy. It only sounds reasonable in the same way startup claim if we can just capture 1% of the X market, while forgetting numbers much smaller exist. Let’s assume super tech they can build that somehow allows vastly faster speeds than we can today ~120 km/s worth of DeltaV. Half that is spent slowing down so we’re talking 0.02% c. Now let’s assume half the time is spent in flight and half the time is spent colonizing stars before launching ships. So now we’re down to 0.01% C. Suddenly 1 Billion years is a more reasonable estimate and even that takes super tech we don’t have any idea how to build and assumes nothing fails. Several more advanced civilizations could be colonizing the galaxy today that are still 10 billion years from finishing.

DennisP 3y ago
Fusion rockets would be able to get over 1% c. I think the theoretical maximum for fusion is around 10%.
- Retric 3y ago
  Fusion rockets might be able to get a sufficiently large spacecraft over 1% c. If you’re instead sending multiple generations of craft and waiting until each succeeds then it’s 1/n %c etc. Colonization using a massive habitat capable of extreme redundancy and asteroid mining could be a completely viable solution to colonization. But such a structure wouldn’t be light. Hitting 1% c could very well take megastructures that a civilization would rather spend on redundant craft etc. We can dream, but we’re nowhere close to being able to say what’s actually viable.

Intralexical 3y ago

> That we see nothing implies intellgent life is rare, short lived, or we're early in the age of the universe. Or it implies that not everybody's first instinct on seeing a vast galaxy is to try to take it over ASAP. If you want resources for quality of life— Gas giants are a thing. If you're an explorer driven by curiosity, then take only samples, leave only memories, right. If you want money— Century-long shipping times with civilization-scaled fuel costs tend to eat into profit margins. If you're worried about survival— genuinely worried about survival, on a level personal enough to motivate action, not just academically or for fun— then the focus is on people you know and care about; all of those are here. In fact, I suspect the ones that see other stars and immediately think "Mine mine all mine!" probably have a higher chance of nuking themselves before they even get out of their star system.

perilunar 3y ago
> That we see nothing implies intellgent life is rare, short lived, or we're early in the age of the universe. > > Or it implies that not everybody's first instinct on seeing a vast galaxy is to try to take it over ASAP. Or it may simply imply that intelligent life is good at hiding and does not want to be seen e.g. the dark forest hypothesis.
- kuchenbecker 3y ago
  Dark forest hypothesis uses lack of evidence as evidence. There is little to back the claim the galaxy is full, BUT if it is full then the Dark Forest could be a reason we haven't detected.

jvmboi 3y ago

If the universe is Einsteinian, I don't think "colonizing" the stars is a thing that makes sense. We might do it once because we are sentimental like that but maybe that's owed to unique psychology owed to unique circumstances on earth. I don't see how you could rationally justify spending this stupefying amount of resources on sending people into the void where, even if all goes well, you can barely talk to them, have no trade and no social contact with them at all.` Basically you are paying to split off a one-way branch of the species. Just consider that if we could colonize Alpha Centauri that means that each message has a 8 year or 1/10 of a human life span roundtrip. What would you even talk about with that kind of latency?

pie420 3y ago
Very shortminded and proto-humancentric thinking. This is all done via AI and automated factories that terraform planets into Von Neumann manufacturing hubs, which then each send millions/billions of Von Neumann's out into the galaxy, each Von Neumann probe containing the tech/machinery to terraform another planet into another Dyson Sphere manufacturing hub. If you're really sentimental about humanity, you can include human DNA on the von neumann probess, and while the von neumann probe is terraforming a new planet, it can also grow humans in vitro. Why would we (or our AI overlords) want to spread through the galaxy like this? Why does cancer spread through it's host? Why did europeans colonize the entire earth? Life is a virus that spreads without limit. "I don't see how you could rationally justify spending this stupefying amount of resources on sending people into the void where, even if all goes well, you can barely talk to them, have no trade and no social contact with them at all." Do you not understand why people invested in early merchant ships in like the 1500s? You spend a lot on a ship, send the ship to trade, and they come back with spice, that you sell at a profit, buy more ships, rinse and repeat. Same here: spend a couple quadrillion dollars, send off some von neumann probes, wait 50 million years, and then see if you've colonized a small cluster of the galaxy, or if your von neumann probe fleet was destroyed by a gamma ray burst or an uncharted supermassive black hole.
- Retric 3y ago
  An immortal might justify sending automated probes to the nearest few systems to eventually collect resources and send them back to you. But collecting resources from 10,000+ light years away just doesn’t make sense. By that point you have long since turned the local star system into a black hole via excess mass.