3 ms·

The speed of light is a tremendous limitation. W/o FTL there's no such thing as "loud alien civilizations" that can "control 40%-50% of [the] universe['s] volu

The speed of light is a tremendous limitation. W/o FTL there's no such thing as "loud alien civilizations" that can "control 40%-50% of [the] universe['s] volume".

XorNot 3y ago
Rather depends on other factors though: you can perfectly well run an interstellar empire with very long communication times and people going into suspended animation for transit. Control strategy simply has to adapt accordingly: i.e. a message probably comes with a fleet sufficient to ensure its obeyed. This was one of the ideas in the Doom novelizations: that the aliens had spent so long travelling that there was little chance of victory because of you attacked a place you took along everything needed for overwhelming victory.
- Mistletoe 3y ago
  Suspended animation may be as impossible as faster than light travel.
  - pfdietz 3y ago
    Much more plausible, IMO.
  - ben_w 3y ago
    We've already got examples of small creatures in suspended animation. I only wish Alcubierre-type drives were as well-developed as that.
- Animats 3y ago
  > Rather depends on other factors though: you can perfectly well run an interstellar empire with very long communication times and people going into suspended animation for transit. Probably not. Historically, a few months of lag is roughly the upper limit for running an empire. The Roman empire got round trip lag down to two months to the distant provinces. The Spanish empire was at 4-5 months of lag for the New World. Holding an empire together with a lag of decades probably won' work.
- cryptonector 3y ago
  > you can perfectly well run an interstellar empire with very long communication times and people going into suspended animation for transit. If travel times are orders of magnitude longer than lifetimes, then you will tend to lose civilizational cohesion. > Control strategy simply has to adapt accordingly: i.e. a message probably comes with a fleet sufficient to ensure its obeyed. What even is the point? The message takes N years to be received by a receiver N light-years away, but travel times will be orders of magnitude longer, so no "fleet" can be sent.
  - exe34 3y ago
    The fleet carries the message. Of course, there's a fair chance that by the time the fleet gets there, the colony is long dead, or has advanced in weaponry in a different but overwhelming direction, so they just barely notice the little flash way out past their oort cloud.
  - XorNot 3y ago
    Ascribing limited-lifespan human motivations to potentially infinite lifespan non-human intelligence is the core mistake here though. You look at running an empire with hundreds of years of message delay as pointless, they may view it as totally necessary. After all - if from your subjective opinion you blink and you're in another star system (hundreds of years later), then are you even worried about that time difference, or are you worried about whether they're still flying the right flags when you get there? (you can imagine a similar arrangement of times working out for social relationships over such timespans - duration might not much matter if everyone sort of agrees they'll wake up for X amount of subjective time before meeting up again in person).
- FrustratedMonky 3y ago
  AI. Instead of FTL, or FTL communication lines, or forms of suspended animation. The ships that are sent out could be run by an AI. Maybe the ships are factory ships to self-replicate. The Grabby could be more like Blindsight.
  - cryptonector 3y ago
    Yes, but then each colony is independent and disconnected from the mother ship. There are people who say that... that's what we are on Earth: a colony started by aliens.
cwillu 3y ago
As stated in the paper: “The second of our three model parameters is the (assumed universal) speed at which grabby civilizations expand. Our model predicts that on average at grabby origin dates, a third to a half of the universe is within grabby-controlled volumes. So if the grabby expansion speed were low, many such volumes should appear quite large and noticeable in our sky. However, as noted by (Olson ’15; Olsen ’17) and discussed in Section 13, if their expansion speed were within ∼25% of lightspeed, a selection effect implies that we are less likely to see than to not see such volumes. Thus if we could have seen them, they would likely be here now instead of us. As we do not now see such volumes, we conclude that grabby aliens, if they exist, expand very fast.”
- cryptonector 3y ago
  They couldn't be cohesive civilizations though, not unless their individual lifetimes were very long.
  - ben_w 3y ago
    While true, a poor choice of name doesn't invalidate the logic. I'd call them "lineages" for this reason, but I don't really expect the name to catch on.
    - cryptonector 3y ago
      It's just not a single cohesive civilization. Though it would be fascinating. Imagine if our world were seeded with life and terraformed (which now would be quite the misnomer) to be able to host the human-like spawn of a human-like "civilization" that very slowly and discontinuously spread through our corner of the galaxy. That would be quite something, though how would we know unless the parent civilization left us clues to this? And they would have to, if they wanted us to eventually further spread the species/whatever. Or maybe we are sui generis and about to embark on such a program. Or maybe we are about to run headlong into another's such program, possibly causing conflict. Or maybe it's all much too unlikely. I wouldn't know.

The speed of light is a tremendous limitation. W/o FTL there's no such thing as "loud alien civilizations" that can "control 40%-50% of [the] universe['s] volume".

XorNot 3y ago

Rather depends on other factors though: you can perfectly well run an interstellar empire with very long communication times and people going into suspended animation for transit. Control strategy simply has to adapt accordingly: i.e. a message probably comes with a fleet sufficient to ensure its obeyed. This was one of the ideas in the Doom novelizations: that the aliens had spent so long travelling that there was little chance of victory because of you attacked a place you took along everything needed for overwhelming victory.

Mistletoe 3y ago
Suspended animation may be as impossible as faster than light travel.
- pfdietz 3y ago
  Much more plausible, IMO.
- ben_w 3y ago
  We've already got examples of small creatures in suspended animation. I only wish Alcubierre-type drives were as well-developed as that.
Animats 3y ago
> Rather depends on other factors though: you can perfectly well run an interstellar empire with very long communication times and people going into suspended animation for transit. Probably not. Historically, a few months of lag is roughly the upper limit for running an empire. The Roman empire got round trip lag down to two months to the distant provinces. The Spanish empire was at 4-5 months of lag for the New World. Holding an empire together with a lag of decades probably won' work.
cryptonector 3y ago
> you can perfectly well run an interstellar empire with very long communication times and people going into suspended animation for transit. If travel times are orders of magnitude longer than lifetimes, then you will tend to lose civilizational cohesion. > Control strategy simply has to adapt accordingly: i.e. a message probably comes with a fleet sufficient to ensure its obeyed. What even is the point? The message takes N years to be received by a receiver N light-years away, but travel times will be orders of magnitude longer, so no "fleet" can be sent.
- exe34 3y ago
  The fleet carries the message. Of course, there's a fair chance that by the time the fleet gets there, the colony is long dead, or has advanced in weaponry in a different but overwhelming direction, so they just barely notice the little flash way out past their oort cloud.
- XorNot 3y ago
  Ascribing limited-lifespan human motivations to potentially infinite lifespan non-human intelligence is the core mistake here though. You look at running an empire with hundreds of years of message delay as pointless, they may view it as totally necessary. After all - if from your subjective opinion you blink and you're in another star system (hundreds of years later), then are you even worried about that time difference, or are you worried about whether they're still flying the right flags when you get there? (you can imagine a similar arrangement of times working out for social relationships over such timespans - duration might not much matter if everyone sort of agrees they'll wake up for X amount of subjective time before meeting up again in person).
FrustratedMonky 3y ago
AI. Instead of FTL, or FTL communication lines, or forms of suspended animation. The ships that are sent out could be run by an AI. Maybe the ships are factory ships to self-replicate. The Grabby could be more like Blindsight.
- cryptonector 3y ago
  Yes, but then each colony is independent and disconnected from the mother ship. There are people who say that... that's what we are on Earth: a colony started by aliens.

cwillu 3y ago

As stated in the paper: “The second of our three model parameters is the (assumed universal) speed at which grabby civilizations expand. Our model predicts that on average at grabby origin dates, a third to a half of the universe is within grabby-controlled volumes. So if the grabby expansion speed were low, many such volumes should appear quite large and noticeable in our sky. However, as noted by (Olson ’15; Olsen ’17) and discussed in Section 13, if their expansion speed were within ∼25% of lightspeed, a selection effect implies that we are less likely to see than to not see such volumes. Thus if we could have seen them, they would likely be here now instead of us. As we do not now see such volumes, we conclude that grabby aliens, if they exist, expand very fast.”

cryptonector 3y ago
They couldn't be cohesive civilizations though, not unless their individual lifetimes were very long.
- ben_w 3y ago
  While true, a poor choice of name doesn't invalidate the logic. I'd call them "lineages" for this reason, but I don't really expect the name to catch on.
  - cryptonector 3y ago
    It's just not a single cohesive civilization. Though it would be fascinating. Imagine if our world were seeded with life and terraformed (which now would be quite the misnomer) to be able to host the human-like spawn of a human-like "civilization" that very slowly and discontinuously spread through our corner of the galaxy. That would be quite something, though how would we know unless the parent civilization left us clues to this? And they would have to, if they wanted us to eventually further spread the species/whatever. Or maybe we are sui generis and about to embark on such a program. Or maybe we are about to run headlong into another's such program, possibly causing conflict. Or maybe it's all much too unlikely. I wouldn't know.