Not alien life, mind you, but crafts require interstellar travel to be plausible, and we have reason to doubt that. Even unmanned Von Neumann probes would have a very hard time arriving to their destination still functioning (never mind braking...), and non-inertial engines presume a violation of known physics so deep, it’s unbelievable we’ve missed all signs of it being possible until now.
While I agree with your general argument, I would like to point out that the aliens don’t have to be from another star system.
It seems that our Solar System has at least a dozen of separate places that could harbor life, from the clouds of Venus to the possible subsurface oceans of Pluto and beyond. And the list mostly considers the life that is similar to our own, requiring warm water (and not, say, solitons of the solar plasma). Extending the list with truly alien forms of life could increase the number of possible cradles to perhaps two dozens (??) in our Solar System alone.
Additionally, perhaps humans are not the first species on Earth that has created a technological civilization. So, theoretically there could be aliens originated from Earth.
One scenario I consider is that a technological civilization (dinosaur descended reptilian hominids?) created super intelligent AI and it killed them. Then it transcended to a higher spatial dimension and exists as computronium in the Earth’s core. Over time, it has grown to regret killing its creators, and we resemble its creators so it’s looking out for us.
It’s a consensus of modern science that higher spatial dimensions exist…
That just sounds like a wild sci-fi plot. Higher spatial dimensions aren’t really a thing either, string theory (which is not consensus) requires them, but they’re “wrapped around”, which means they’d be pretty useless for any actual practical purposes. And string theory has yet to make a single falsifiable prediction anyway.
While I agree with your general argument, I would like to point out that the aliens don’t have to be from another star system.
It seems that our Solar System has at least a dozen of separate places that could harbor life, from the clouds of Venus to the possible subsurface oceans of Pluto and beyond. And the list mostly considers the life that is similar to our own, requiring warm water (and not, say, solitons of the solar plasma). Extending the list with truly alien forms of life could increase the number of possible cradles to perhaps two dozens (??) in our Solar System alone.
Additionally, perhaps humans are not the first species on Earth that has created a technological civilization. So, theoretically there could be aliens originated from Earth.
Other lifeforms in the solar system? Sure. Other technological civilizations that we somehow haven’t detected? Waaaaaay unlikely.
One scenario I consider is that a technological civilization (dinosaur descended reptilian hominids?) created super intelligent AI and it killed them. Then it transcended to a higher spatial dimension and exists as computronium in the Earth’s core. Over time, it has grown to regret killing its creators, and we resemble its creators so it’s looking out for us.
It’s a consensus of modern science that higher spatial dimensions exist…
This scenario has too many burdensome details to be given much attention, except as one example from an extremely large space of possibilities.
That just sounds like a wild sci-fi plot. Higher spatial dimensions aren’t really a thing either, string theory (which is not consensus) requires them, but they’re “wrapped around”, which means they’d be pretty useless for any actual practical purposes. And string theory has yet to make a single falsifiable prediction anyway.