Well, we do know that interstellar travel is possible, just currently very hard. It’s a technological issue, not a physical one. I can certainly imagine slow travel, a few thousands km/s, being possible with nuclear rocket propulsion or other tech. Getting a spaceship-size object traveling at an appreciable fraction of the speed of light is a different story, anything like that would create observational artifacts visible from far away, so those probably aren’t anywhere in the observed past light cone. But I am not sure how this is related to the evaluation of the odds of AIpocalypse.
Well, we do know that interstellar travel is possible, just currently very hard. It’s a technological issue, not a physical one. I can certainly imagine slow travel, a few thousands km/s, being possible with nuclear rocket propulsion or other tech. Getting a spaceship-size object traveling at an appreciable fraction of the speed of light is a different story, anything like that would create observational artifacts visible from far away, so those probably aren’t anywhere in the observed past light cone. But I am not sure how this is related to the evaluation of the odds of AIpocalypse.