4 ms·

Why isn't at least one species expanding across the cosmos though? The light speed limit isn't really much of a hurdle for cosmic timescales. The guy on cool w

Why isn't at least one species expanding across the cosmos though? The light speed limit isn't really much of a hurdle for cosmic timescales. The guy on cool worlds YouTube channel (Department of Astronomy, Colombia) has argued that we're still in the early days. The conditions for intelligent life in the galaxy hasn't been around for that long.

kstenerud 2y ago
Perhaps there is, but once again it would have to be visible from our light cone in order for us to even be capable of detecting it. Even with a civilization of 100,000 or even a million years that's still tiny and highly unlikely to happen within a timeframe that intersects with our small window of awareness. And even if these aliens have cracked FTL travel, who's ever going to find our little planet on the ass end of some mediocre galaxy, with an EM emissions bubble that has only covered 100 light years so far? Needle in a haystack.
- Gravityloss 2y ago
  Hmm, let's say there's 100 billion stars in our galaxy and one billion habitable planets. Assuming we are average, half, or 500 million have civilizations older than ours. We could assume some sort of distribution where we could say 10% are older than a million years. So 50 million civilizations older than a million years in the milky way. In a million years moving at 0.1c you move 100,000 light years, or across the whole galaxy. They could have been here already before modern humans even existed.
  - worldsayshi 2y ago
    Seeing how it took earth 4 billion years to figure out how to get inhabitants to set foot on another stellar body the rise of intelligence may be the unlikely event here. Perhaps it's much more likely to have happened elsewhere in the galaxy 4 more billion years from now. If I remember correctly, stars with our particular properties haven't been around for too long. I recommend looking into cool worlds lab since you seem to like inferring from the numbers.
    - mithametacs 2y ago
      We've set foot on only 1 other stellar body. Luna is sort of made from the Earth. And it's so close that Earth has a stronger pull on it than Sun. So we have set foot on another stellar body, sure. But we also... kind of haven't. And then we had to retreat from it anyway. Homo sapiens, hunter champions, arrived at an uninhabited body and were outmatched. Way to go, smartest species we know of. You've done jack shit.
myrmidon 2y ago
Maybe interstellar colonization is just never gonna be worth it? We could already colonize Antarctica, or the sea-- those are easier to reach, supply and colonize than other planets, but we are not trying. Most of our past exploration/settling efforts happened because there was some gain to be had; it seems quite plausible (if somewhat bleak) to me that interstellar travel could just remain pointlessly expensive regardless of technological progress.
- aflukasz 2y ago
  > We could already colonize Antarctica, or the sea-- those are easier to reach, supply and colonize than other planets, but we are not trying. On the other hand - we were and still are present on the Antarctica, have a permanent base on the South Pole etc.
nonameiguess 2y ago
It may simply not be worth it. Outside of sheer curiosity, there are two reasons I can think of to leave your own solar system. One is overcoming resource scarcity. But interstellar space is extremely hostile to anything that isn't a cloud of dust and there are no resources available for thousands if not millions of years. If you've developed technology already to overcome the need for resources and are hardened to endure conditions for that span of time, you may overcome the resource limits of your own solar system anyway. The second reason is to escape the death of your own sun. That takes long enough that far fewer lifeforms would be expected to even face that challenge compared to resource scarcity. If you manage to sustain a high-level civilization that can overcome resource scarcity and conquer the challenges of interstellar travel for the billions of years it takes a star to die, maybe you can simply prevent that death by technological means we could not possibly foresee or understand? Those are hand-wavy answers, but this is sort of the problem. We're imagining near god-like beings here and asking why they don't behave the way humans have historically behaved with respect to exploring and colonizing remote parts of our own planet. The analogy breaks down at some point and we have no idea what beings capable of that kind of thing would even want to do. Even our best sci-fi imagines answers that are pulled out of imaginary asses but frankly no less plausible than anything else anyone here will come up with. The builders of the expanse series expanded to a few hundred systems but then simply didn't need to expand any further. They figured out how to stop fusion and star-aging and tapped into energy sources from other universes (then got killed off anyway, but seemingly would not have kept expanding). The monolith aliens of the space odyssey series evolved into a non-material form that was actually here the whole time but we had no means of detecting them.

kstenerud 2y ago

Perhaps there is, but once again it would have to be visible from our light cone in order for us to even be capable of detecting it. Even with a civilization of 100,000 or even a million years that's still tiny and highly unlikely to happen within a timeframe that intersects with our small window of awareness. And even if these aliens have cracked FTL travel, who's ever going to find our little planet on the ass end of some mediocre galaxy, with an EM emissions bubble that has only covered 100 light years so far? Needle in a haystack.

Gravityloss 2y ago
Hmm, let's say there's 100 billion stars in our galaxy and one billion habitable planets. Assuming we are average, half, or 500 million have civilizations older than ours. We could assume some sort of distribution where we could say 10% are older than a million years. So 50 million civilizations older than a million years in the milky way. In a million years moving at 0.1c you move 100,000 light years, or across the whole galaxy. They could have been here already before modern humans even existed.
- worldsayshi 2y ago
  Seeing how it took earth 4 billion years to figure out how to get inhabitants to set foot on another stellar body the rise of intelligence may be the unlikely event here. Perhaps it's much more likely to have happened elsewhere in the galaxy 4 more billion years from now. If I remember correctly, stars with our particular properties haven't been around for too long. I recommend looking into cool worlds lab since you seem to like inferring from the numbers.
  - mithametacs 2y ago
    We've set foot on only 1 other stellar body. Luna is sort of made from the Earth. And it's so close that Earth has a stronger pull on it than Sun. So we have set foot on another stellar body, sure. But we also... kind of haven't. And then we had to retreat from it anyway. Homo sapiens, hunter champions, arrived at an uninhabited body and were outmatched. Way to go, smartest species we know of. You've done jack shit.

myrmidon 2y ago

Maybe interstellar colonization is just never gonna be worth it? We could already colonize Antarctica, or the sea-- those are easier to reach, supply and colonize than other planets, but we are not trying. Most of our past exploration/settling efforts happened because there was some gain to be had; it seems quite plausible (if somewhat bleak) to me that interstellar travel could just remain pointlessly expensive regardless of technological progress.

aflukasz 2y ago
> We could already colonize Antarctica, or the sea-- those are easier to reach, supply and colonize than other planets, but we are not trying. On the other hand - we were and still are present on the Antarctica, have a permanent base on the South Pole etc.

nonameiguess 2y ago

It may simply not be worth it. Outside of sheer curiosity, there are two reasons I can think of to leave your own solar system. One is overcoming resource scarcity. But interstellar space is extremely hostile to anything that isn't a cloud of dust and there are no resources available for thousands if not millions of years. If you've developed technology already to overcome the need for resources and are hardened to endure conditions for that span of time, you may overcome the resource limits of your own solar system anyway. The second reason is to escape the death of your own sun. That takes long enough that far fewer lifeforms would be expected to even face that challenge compared to resource scarcity. If you manage to sustain a high-level civilization that can overcome resource scarcity and conquer the challenges of interstellar travel for the billions of years it takes a star to die, maybe you can simply prevent that death by technological means we could not possibly foresee or understand? Those are hand-wavy answers, but this is sort of the problem. We're imagining near god-like beings here and asking why they don't behave the way humans have historically behaved with respect to exploring and colonizing remote parts of our own planet. The analogy breaks down at some point and we have no idea what beings capable of that kind of thing would even want to do. Even our best sci-fi imagines answers that are pulled out of imaginary asses but frankly no less plausible than anything else anyone here will come up with. The builders of the expanse series expanded to a few hundred systems but then simply didn't need to expand any further. They figured out how to stop fusion and star-aging and tapped into energy sources from other universes (then got killed off anyway, but seemingly would not have kept expanding). The monolith aliens of the space odyssey series evolved into a non-material form that was actually here the whole time but we had no means of detecting them.