3 ms·

I wonder how much that changes the final probability. I think the biggest piece is instead of both able to detect each other only one will (the other will proba

I wonder how much that changes the final probability. I think the biggest piece is instead of both able to detect each other only one will (the other will probably be dead by the time the information gets back the other way) which halves the chances of detecting another civilization. Beyond that, given sufficiently short civilization lifespans vs the age of the universe they can randomly appear in and a relatively uniform rate of random occurrence, I don't think "a random civilization appeared x years ago x light years away for the timing to work out" actually ends up being any less likely than "a random civilization appeared at the same time". It feels like it should but really if you just take the chance it'd happen normally and say "well, there is an equal chance a civilization could have developed x years prior" you correct for the time for traversing the distance without changing the probability. The main thing the speed of light prevents is a single civilization staying together as a galaxy sized empire.

Vox_Leone 3y ago
>The main thing the speed of light prevents is a single civilization staying together as a galaxy sized empire. It seems to me that, in principle, a ruling class could set itself apart from humanity and conduct the business of a galactic government -- ahem, a galactic enlightened dictatorship, with its own timing. For example, Alice and Bob live on Trantor, and are employees of the Galactic Federation. They constantly travel [at the same fractions of the speed of light] to clusters located in different galactic hemispheres, and, thanks to almost identical rates of time dilation in their [perhaps carefully chosen] travels, they meet every weekend of their proper time. They live happily as a family in the headquarters of the government, to the rhythm of the passing of countless generations on the myriad planets of the federation.
- zamadatix 3y ago
  The main issue with this is a week to the traveller crossing the galaxy near the speed of light still requires civilization to stay together for 100,000 years without them. The second issue is it's not as attractive as it sounds. Travelling 1/10th the galaxy in a proper time of 5 days requires a trip of a constant 2400 G's. Maybe solvable once your civilization has already overcome the Fermi paradox (probably don't need bodies at that point) though.

Vox_Leone 3y ago

>The main thing the speed of light prevents is a single civilization staying together as a galaxy sized empire. It seems to me that, in principle, a ruling class could set itself apart from humanity and conduct the business of a galactic government -- ahem, a galactic enlightened dictatorship, with its own timing. For example, Alice and Bob live on Trantor, and are employees of the Galactic Federation. They constantly travel [at the same fractions of the speed of light] to clusters located in different galactic hemispheres, and, thanks to almost identical rates of time dilation in their [perhaps carefully chosen] travels, they meet every weekend of their proper time. They live happily as a family in the headquarters of the government, to the rhythm of the passing of countless generations on the myriad planets of the federation.

zamadatix 3y ago
The main issue with this is a week to the traveller crossing the galaxy near the speed of light still requires civilization to stay together for 100,000 years without them. The second issue is it's not as attractive as it sounds. Travelling 1/10th the galaxy in a proper time of 5 days requires a trip of a constant 2400 G's. Maybe solvable once your civilization has already overcome the Fermi paradox (probably don't need bodies at that point) though.