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I suppose this does tell us something: there are no ancient super high tech hyper-expansionary civilizations in this galaxy, or at least not near us. That coul

by api 2y ago

I suppose this does tell us something: there are no ancient super high tech hyper-expansionary civilizations in this galaxy, or at least not near us. That could mean a lot of things including just chance. There could be galaxies out there that have in fact been fully colonized.

rbanffy 2y ago
Expanding is a significant use of resources. It requires consistent dedication over very long timeframes to succeed. Just look at how long it's taking to even have a permanent presence (not even close to a self-sustaining colony) on the Moon, which is one light-second away.
- api 2y ago
  That’s one reason I’m skeptical of ultra-grabby hyper-expansionist aliens. Human cultures have become less obsessively expansionist as they’ve become more educated and advanced, with rare and usually transient exceptions. Imperialism usually burns out after a while as the cost begins to exceed the benefit. I could see a universe of mostly steady state civilizations that experience occasional bouts of expansionism or the sending of things like the Nauvoo from The Expanse. But those are transient events. This would greatly increase the time required for the galaxy to become saturated with life as per Fermi paradox models. It might happen eventually, meaning if we wait long enough some alien Mormons might show up. (The Expanse reference.) Then consider that intelligence is probably a recent (on cosmic time scales) phenomenon due to metallicity. Previous generations of stars and planets probably lack the mineral diversity to support complex intelligent life.
  - pfdietz 2y ago
    I see pretty much the opposite. There will be strong selection for expansionist cultures and species. As long as the universe is mostly unoccupied, expansion means increasing your share of the total population. Relatively static cultures will simply become irrelevant compared to their expansionist competitors. The experience on Earth recently is in the context of a world where all places that can be occupied (at the current tech level) have been. The selection effect will operate at the biological level as well. Currently on Earth birth rates are declining. Modern civilization is acting like a kind of pesticide. But like any pesticide, it's going to select for resistance. This will likely mean more people will have an increased desire to have children. Selecting for this may take a while, but on the time scales involved in this thread it would happen very quickly. In the long term, all societies in which selection is allowed to operate will push up against limits and be in states of Malthusian equilibrium. To counter this would require an unreasonable uniformity of control across time and space. All ET species, at all points in their history once they can undertake colonization, will have to exert rigid control on their societies and biology. Any defections from this uniformity will explode exponentially and overwhelm those who are not controlled. Metallicity is not a good argument, since there are zones, even in our own galaxy, with higher metallicity. Closer in to the center, for example. https://www.nature.com/articles/s41550-023-01977-z https://www.nature.com/articles/s41550-023-01977-z
pfdietz 2y ago
They could be galaxies that have been fully colonized, but searches for them have turned up nothing. Specifically: if by "fully colonized" we mean fully exploiting the energy resources of the galaxy, this would show up in the spectrum of emitted radiation, with energy being emitted as waste heat instead of starlight. Infrared surveys put the fraction of such fully colonized galaxies at less than 1 in 100,000, and consistent with none at all.

by api 2y ago

rbanffy 2y ago

Expanding is a significant use of resources. It requires consistent dedication over very long timeframes to succeed. Just look at how long it's taking to even have a permanent presence (not even close to a self-sustaining colony) on the Moon, which is one light-second away.

api 2y ago
That’s one reason I’m skeptical of ultra-grabby hyper-expansionist aliens. Human cultures have become less obsessively expansionist as they’ve become more educated and advanced, with rare and usually transient exceptions. Imperialism usually burns out after a while as the cost begins to exceed the benefit. I could see a universe of mostly steady state civilizations that experience occasional bouts of expansionism or the sending of things like the Nauvoo from The Expanse. But those are transient events. This would greatly increase the time required for the galaxy to become saturated with life as per Fermi paradox models. It might happen eventually, meaning if we wait long enough some alien Mormons might show up. (The Expanse reference.) Then consider that intelligence is probably a recent (on cosmic time scales) phenomenon due to metallicity. Previous generations of stars and planets probably lack the mineral diversity to support complex intelligent life.
- pfdietz 2y ago
  I see pretty much the opposite. There will be strong selection for expansionist cultures and species. As long as the universe is mostly unoccupied, expansion means increasing your share of the total population. Relatively static cultures will simply become irrelevant compared to their expansionist competitors. The experience on Earth recently is in the context of a world where all places that can be occupied (at the current tech level) have been. The selection effect will operate at the biological level as well. Currently on Earth birth rates are declining. Modern civilization is acting like a kind of pesticide. But like any pesticide, it's going to select for resistance. This will likely mean more people will have an increased desire to have children. Selecting for this may take a while, but on the time scales involved in this thread it would happen very quickly. In the long term, all societies in which selection is allowed to operate will push up against limits and be in states of Malthusian equilibrium. To counter this would require an unreasonable uniformity of control across time and space. All ET species, at all points in their history once they can undertake colonization, will have to exert rigid control on their societies and biology. Any defections from this uniformity will explode exponentially and overwhelm those who are not controlled. Metallicity is not a good argument, since there are zones, even in our own galaxy, with higher metallicity. Closer in to the center, for example. https://www.nature.com/articles/s41550-023-01977-z https://www.nature.com/articles/s41550-023-01977-z

pfdietz 2y ago

They could be galaxies that have been fully colonized, but searches for them have turned up nothing. Specifically: if by "fully colonized" we mean fully exploiting the energy resources of the galaxy, this would show up in the spectrum of emitted radiation, with energy being emitted as waste heat instead of starlight. Infrared surveys put the fraction of such fully colonized galaxies at less than 1 in 100,000, and consistent with none at all.