Kind of a worldbuilding stackexchange response, yet other reasons aliens might not interact (from a "they exist" perspective).
Hitchhiker's Guide - We're just not very interesting. The aliens exist, have noticed the Earth, yet don't care, because we don't really do much from a galactic perspective. Mostly Harmless.
Star Trek - The aliens exist, yet have some external reason to not interact, like a diplomatic treaty.
Star Wars - The aliens exist, there's just too many other aliens to deal with already (Republic). The situation external to Earth is some kind of massive bureaucracy that makes doing much other than dealing with the bureaucracy nearly unmanageable.
Culture Novels - The aliens exist, yet don't interact because we're the equivalent of barbarous housepets from their perspective.
Forever War - The aliens exist, may have noticed, they're just too busy fighting some really long term war with each other to care.
Stargate - The aliens exist, just view the Earth as a non-threatening farm to be harvested eventually.
The Algebraist - Aliens exist, yet the most common form is just really weird from a human perspective (like gaseous objects in cloud giants). Flesh bipeds are not all that interesting, or perhaps discounted because "intelligence only exists in these forms."
Dragon Ball Z or Warhammer 40k - Aliens exist, yet the Earth is boring. It's mostly calm bickering a lot of the time. Where are the enormous battles and massive weapons? No titanic fights that lay waste to the surface?
I never understood the aliens as harvesters as a threat movie plot / Hawking logic. There is SO much stuff in space. All of the stuff. Why care about our stuff? Intergalactic highway imminent domain? Just chart a different course. There’s no reason other than to mess with us for fun like dolphins jacking with a pufferfish. I guess maybe I’ve stumbled onto a sci-fi short story idea.
I think the biological information on earth would likely be extremely valuable. Our DNA took an absurdly long time to evolve, and would probably be almost impossible to acquire with simulations given it spans from microscopic to macroscopic factors. Works of artistic or cultural significance probably have a decent chance as well, given the value we place on those even from ancient or foreign cultures. Whether our biosphere/temperate planet has value probably depends a lot on your assumptions about how hard terraforming is for super-civilizations and how compatible life is.
On the other hand I agree our natural resources are likely worthless. I always laugh at that scientology movie, Battlefield Earth, where the aliens invade, then inslave humans to dig in Earth's gold mines with pickaxes. Maybe the most troublesome possible way you could acquire gold as a spacefairing race.
As a hobby project I'm making a video game about aliens looting museums and zoos for items of cultural and biological value. Mostly because I find the idea of little green men busting up the Louvre then blasting off to be very funny. The zoo angle is a little nonsensical if you consider how much DNA is shared, but obviously scooping up pondscum is a less interesting scenario.
Sometimes we do, or to avoid all kinds of specially designated species. There are reams of complaints throughout construction history about being unlucky enough for your bright new infrastructure project to be heading right for some politically or socially de jour habitat that activists decide they want to protect.
Who's to say that there doesn't exist a cosmic version of Greenpeace that has been actively pamphleteering some galactic government into not star-lasering(1) our little green and blue anthill to a husk for its latest celestial mega-infrastructure project?
Thanks. Forgot this version. There's also a "slightly" different version of "we exist in a different timeframe / timespeed / dimension."
Star Trek TNG "Time's Array Part 1/2" had the alternative overlaid dimension variation.
TNG "Timescape" had the alternate timeframe / timespeed with the Warbird / Enterprise existing in a different time than the runabout, as well as fruit that rapid aged / decomposed relative to the crew members (and the fun issue of accidentally walking into a bubble of AGE+50yrs).
These articles should spend more time trying to explain the scale of galaxies and superclusters, plus the sheer number of stars vs. physics. That puts in so much perspective: even if we had warp 11 drives it would be essentially impossible to look for alien life on every star system. We’ll never find each other because the universe is too damn big.
That's assuming that's the only mode of travel. There could be worm holes, or things we can't imagine.
Also if the goal was to find life, searching would not be optimal. It would be better to launch pods that self expand to nearby planet, make their own pods, and go to the next nearby planets.
The universe is so vast, that I think even self-replicating probes traveling via wormholes would not be able to cover even a tiny fraction of the existing planets before their suns die out. The universe is really really really big.
13.7 billion years old, with a window of detection of about 1,000,000 years (evolution to self-extermination).
Maybe I'm just a dumb human, but I really don't see why a supergenius race would invest the resources in scouring the universe. Unless it was their manifest destiny. In my head a narrative to address this crosses from sci-fi into fantasy.
Even if there is a wormhole or some crazy sci-fi thing we haven’t thought of, there are a million trillion stars. Basically invisible. Unless you suggest some technology appears that allows an entity to travel to every star and observe it for billions of years. I’d love to hear a sci-fi proposal that covers this without invoking omniscient gods or the supernatural.
Multidimensional beings that transcend time and/or space. Not necessarily dieties, but it kind of is from our perspective.
Another night be that consciousness exists at many physical levels. Just like you are made of trillions of automata of cells and bacteria, which are played out by proteins and DNA, maybe the universe is a single consciousness, and we are but one part. Or a part of a part.
> We’ll never find each other because the universe is too damn big.
Intra-galaxy is certainly not too big.
Even at slow, sub-relativistic speeds, our local galaxy should be fully colonized by now--whether by self-replicating automation or life. This is the paradox.
Hitchhiker's Guide - We're just not very interesting. The aliens exist, have noticed the Earth, yet don't care, because we don't really do much from a galactic perspective. Mostly Harmless.
Star Trek - The aliens exist, yet have some external reason to not interact, like a diplomatic treaty.
Star Wars - The aliens exist, there's just too many other aliens to deal with already (Republic). The situation external to Earth is some kind of massive bureaucracy that makes doing much other than dealing with the bureaucracy nearly unmanageable.
Culture Novels - The aliens exist, yet don't interact because we're the equivalent of barbarous housepets from their perspective.
Forever War - The aliens exist, may have noticed, they're just too busy fighting some really long term war with each other to care.
Stargate - The aliens exist, just view the Earth as a non-threatening farm to be harvested eventually.
The Algebraist - Aliens exist, yet the most common form is just really weird from a human perspective (like gaseous objects in cloud giants). Flesh bipeds are not all that interesting, or perhaps discounted because "intelligence only exists in these forms."
Dragon Ball Z or Warhammer 40k - Aliens exist, yet the Earth is boring. It's mostly calm bickering a lot of the time. Where are the enormous battles and massive weapons? No titanic fights that lay waste to the surface?