Grabby Aliens, The Fermi Paradox

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This note is primarily based on Grabby Aliens & The Fermi Paradox by Isaac Arthur.
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Grabby Aliens & The Fermi Paradox

Inspired/based on If Loud Aliens Explain Human Earliness, Quiet Aliens Are Also Rare by Hanson, Martin, McCarter, & Paulson.

By modeling three variables related to colonization of space, it seems plausible values lead to only one conclusion making sense:

  • Alien civilizations are rare.
  • Quiet civilizations are not more common and loud expansionist civilizations.
  • We don't see aliens because we are early.

Based on these ideas, this galaxy is uninhabited (besides us), and it's half a billion lightyears at a minimum to anyone high-tech. Alien life isn't rare, it's just rare now. Anyone like us out there is likewise wondering the same things and coming to the same conclusions.

This model is incompatible with the Zoo Hypothesis because that would allow for civilizations to expand inside of other civilizations. It supports Rare Earth and Rare Intelligence solutions to the Fermi Paradox.

Loud aliens:

  1. Expand fast.
  2. Last long.
  3. Leave marks.

Grabby aliens:

  1. Expand their controlled volume at a set speed.
  2. Clearly change their volume.
  3. Are born according to a power law in time (what?), and not within already-controlled volumes.
  4. Do not die except to other grabby aliens.

The biggest potential modification of this model is based on whether or not intergalactic travel requires a maximum travel speed (due to collision risk), and what that speed is.

Assuming we are in the middle of civilization emergence (with 4 billion years on either side of now) and civilizations generally expand at 0.8c, the model predicts:

  • Galactic civilizations control 1/5th to 1/4th of the observable universe, but 65% of the observable universe cannot yet see this. (Which is why we don't see it.)
  • It is estimated that 62% of civilizations will grow larger than we can.
  • We can safely colonize our supercluster before encountering another civilization.
  • Roughly 7,000 civilizations will appear in the observable universe.

How early we are doesn't change the model of expansion, but changes how far we can go and for how long before we encounter another civilization.

Genocidal policies don't work well (on an intergalactic scale) because no one likes that.

Ideas for what to call a K4 civilization, since many of these would be K4: Average Hanson Bubble or Grabby Alien Civilization (GAC). (The term Galactic Civilization or GC was used throughout most of this source material.)

References: Firstborn, Dyson Dilemma, Great Filters, Doomsday Argument, Hard-Steps Model, Zoo Hypothesis, Rare Earth, Rare Intelligence, Fermi Paradox Compendium, Alien Civilizations, Generation Ships, Extragalactic Sanctuaries.

#futurism #Isaac-Arthur #fermi-paradox

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