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Thread: What do you think is the most likely explanation for the Fermi paradox?

  1. #1321
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    Quote Originally Posted by 7cscb View Post
    And, regardless, we will likely expel much mass in our interstellar travels, which is not Closed.
    Mass expelled from an interstellar vessel will be propellant, not from the life supporting biosphere. A separate system entirely. We don't use the breathing oxygen inside an airplane cabin to run the jets.

    Now, any sealed chamber is imperfect. There will be some material losses from inside the starship biosphere, that's inevitable, and replacement volatiles will have to be carried. But the more closure the builders can achieve, the better for life supporting purposes. So they'll aim high.

    For an orbital habitat replenishment is easier, because there's asteroids and comets to mine, but high degrees of closure of the internal material cycles is still a significant goal, especially as the habitats are being established.
    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

  2. #1322
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    Even with VERY conservative assumptions the galaxy fills within one eon:
    https://www.centauri-dreams.org/2021...ic-settlement/
    SHARKS (crossed out) MONGEESE (sic) WITH FRICKIN' LASER BEAMS ATTACHED TO THEIR HEADS

  3. #1323
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    Quote Originally Posted by Tom Mazanec View Post
    Even with VERY conservative assumptions the galaxy fills within one eon:
    https://www.centauri-dreams.org/2021...ic-settlement/
    Zero is a conservative estimate

    I have already discussed here why I don't believe the colonize-a-whole-galaxy scenario is plausible, let alone a default assumption. A number of posters have come back with "but it only takes one!". My response is, it only takes none to explain what we see. We know we have not detected any technosignatures; Occam's old saw says "there's no technosignatures to find" would be the most likely reason for that.

    IF there's another species with minds, and IF they do get out of their home star system, there's still no particular reason to settle every single star in any galaxy. Yes, "life spreads"... in nature. But by definition a civilization that achieves star travel is an artificial construct that does things on purpose, they need not stick to blind imperatives.

    Also, life growing in a glacier or desert sand does not need to expend massive amounts of energy to adapt; but the physics of relativity and motion necessitate that all forms of interstellar travel will require the commitment of vast power and resources. Especially in-person travel with the intent to colonize. That's always going to be expensive, probably even to a star-system-wide economy.

    A generation ship or "slowboat" would be cheaper in energy but basically require a portable civilization. That also seems like a nontrivial commitment of resources. Either way, fast or slow, it's not ever going to be something a society does casually or without good cause at any tech level. And it almost certainly won't be a priority for a colony system still bootstrapping its industries.
    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

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