4 ms·

The real question is whether any "filters" are really needed. Spacetime alone is sufficient to explain the apparent absence of detectable technological civilis

by qayxc 4y ago

The real question is whether any "filters" are really needed. Spacetime alone is sufficient to explain the apparent absence of detectable technological civilisations. There could be a Dyson Swarm in the making right now, but even if it's "just" 100 light years away, we wouldn't be able to notice until 100 years from now. Same with signals. Any alien civilisation monitoring us would need to be closer than 50 or so light years in order to send a message directed at us that we'd be able to detect now (e.g. radio technology ~100 years ago -> 50 years to get that information to "them", and another 50 years until we'd receive a message).

roywiggins 4y ago
Right, but the galaxy is 13 billion years old and only 100,000 light years wide. We could theoretically detect any operating Dyson swarm as long as it was in operation 100,000 years ago or longer, and there's a 10 billion years of "longer" for someone to have built them. We don't have a view of what exactly is happening right now across the other side of the galaxy but (on the timescale of the galaxy) our view isn't that out of date. If civilizations are common it would be weird if none of them had more than a hundred thousand year head-start on us. That sort of timing would be freakishly coincidental on a billion-year timescale, like everyone finishing a marathon a tenth of a second apart despite having started half an hour earlier or later.
- qayxc 4y ago
  > We don't have a view of what exactly is happening right now across the other side of the galaxy We don't have a full view of the other side of the galaxy. A lot of the galaxy is invisible to us (blocked by dust and stars) and we haven't even surveyed all visible stars for techno-signatures. This makes it kind of weird to jump to conclusions based on what little data we actually have.
  - deleted 4y ago
    [deleted]

by qayxc 4y ago

roywiggins 4y ago

Right, but the galaxy is 13 billion years old and only 100,000 light years wide. We could theoretically detect any operating Dyson swarm as long as it was in operation 100,000 years ago or longer, and there's a 10 billion years of "longer" for someone to have built them. We don't have a view of what exactly is happening right now across the other side of the galaxy but (on the timescale of the galaxy) our view isn't that out of date. If civilizations are common it would be weird if none of them had more than a hundred thousand year head-start on us. That sort of timing would be freakishly coincidental on a billion-year timescale, like everyone finishing a marathon a tenth of a second apart despite having started half an hour earlier or later.

qayxc 4y ago
> We don't have a view of what exactly is happening right now across the other side of the galaxy We don't have a full view of the other side of the galaxy. A lot of the galaxy is invisible to us (blocked by dust and stars) and we haven't even surveyed all visible stars for techno-signatures. This makes it kind of weird to jump to conclusions based on what little data we actually have.
- deleted 4y ago
  [deleted]