3 ms·

The Great Filter is only one possible answer to the Fermi Paradox.

0xDEAFBEAD 3mo ago
The Milky Way is almost 14 billion years old. The Milky Way is perhaps 100K light-years in diameter. If you can travel at 0.1c you could colonize the Milky Way in perhaps around a million years, less than 0.01% of the age of the Milky Way. So, either there's a filter that's blocked interstellar colonization... or it has occurred already, and we just aren't aware of it (some sort of dark forest thing / we are being secretly watched by an extraterrestrial civilization). (This is a haunted galaxy either way!)
- triceratops 3mo ago
  > If you can travel at 0.1c you could colonize the Milky Way in perhaps around a million years There's no reason to believe a civilization is capable of million year projects.
  - 0xDEAFBEAD 2mo ago
    You mean there's some filter which prevents civilizations from developing that capability? ;-)
    - triceratops 2mo ago
      If lack of interest is a filter, sure. Not an especially alarming one though.
  - pfdietz 2mo ago
    There is no need for an organized, unified project for life to spread across the galaxy, any more than there's a need for a unified effort for bacteria and fungi to consume some tasty organic matter, or for humans to have spread across Earth in prehistory.
- antonvs 2mo ago
  These sort of calculations are nothing but examples of how a bad model gives bad results. In this case, the model is bad because it's underspecified. Saying "I have a bad model but there's some unknown Great Factor which would make it a good model" isn't very convincing. There are myriad factors: the biological challenges of space travel constitute a long list in itself; the economics and politics involved (ROI on any useful timeframe for interstellar travel is zero); the engineering challenges (the vast majority of interstellar travel attempts will result in the death of all crew somewhere in interstellar space); the fact that over million-year timescales, species evolve and change - humans are only around 30% of a million years old.

The Milky Way is almost 14 billion years old. The Milky Way is perhaps 100K light-years in diameter. If you can travel at 0.1c you could colonize the Milky Way in perhaps around a million years, less than 0.01% of the age of the Milky Way. So, either there's a filter that's blocked interstellar colonization... or it has occurred already, and we just aren't aware of it (some sort of dark forest thing / we are being secretly watched by an extraterrestrial civilization). (This is a haunted galaxy either way!)

triceratops 3mo ago
> If you can travel at 0.1c you could colonize the Milky Way in perhaps around a million years There's no reason to believe a civilization is capable of million year projects.
- 0xDEAFBEAD 2mo ago
  You mean there's some filter which prevents civilizations from developing that capability? ;-)
  - triceratops 2mo ago
    If lack of interest is a filter, sure. Not an especially alarming one though.
- pfdietz 2mo ago
  There is no need for an organized, unified project for life to spread across the galaxy, any more than there's a need for a unified effort for bacteria and fungi to consume some tasty organic matter, or for humans to have spread across Earth in prehistory.
antonvs 2mo ago
These sort of calculations are nothing but examples of how a bad model gives bad results. In this case, the model is bad because it's underspecified. Saying "I have a bad model but there's some unknown Great Factor which would make it a good model" isn't very convincing. There are myriad factors: the biological challenges of space travel constitute a long list in itself; the economics and politics involved (ROI on any useful timeframe for interstellar travel is zero); the engineering challenges (the vast majority of interstellar travel attempts will result in the death of all crew somewhere in interstellar space); the fact that over million-year timescales, species evolve and change - humans are only around 30% of a million years old.