I don't believe FTL travel is possible, but if it were, the Fermi Paradox would seem to suggest it isn't obvious or trivial. It might require burning the mass energy of an entire star just to open a wormhole or hacking the matrix and forking the physics engine or sacrificing us to their chaos god patrons or something.

I think I'd rather deal with the aliens who just have really good rockets. At least we could potentially comprehend the rulebook they play by. Who even knows what the hell the Walkers of Sigma 957 are about?

Also, FTL technology existing would naturally abate the prospects of interstellar war under the Dark Forest theory, because it means FTL communication is possible; and factions that can communicate with each other quickly are far less likely to fight each other. This was, at least in the first book, a (iirc stated) reason why the Dark Forest theory exists.

Of note: It might not require the outrageous levels of technology you might expect to accelerate technology to the delta-v 3I/ATLAS is traveling at, simply because there are absolutely star systems near ours already traveling at a pretty large sun-relative delta-v. We get a ton of galaxy-relative velocity for free from our solar system; we just have to shoot the probe at slower solar systems. Putting (and surviving) biological life in there, however, is a different matter.

Spoiler alert!

Edit: the book is "The Road not Taken"

There's a scifi story about a civilization stumbling upon how to achieve FTL travel. In the story, the tech is at the same time very simple and very unexpected. Anyways, they go explore the galaxy and invade and conquer with their primitive ships, which are little more than tin buckets. Their weapons technology is on the flintlock gun level.

(A tragic kind of) hilarity ensues when they stumble upon Earth with its completely unexpected, incredibly advanced weaponry. IIRC in the story most civilizations find FTL travel pretty early. Just Earth didn't happen upon it and instead had time to develop advanced weaponry, computers, etc.

Interestingly enough, the same world ending technology can be used for interstellar travel & could have been used since the 1950s!

https://en.m.wikipedia.org/wiki/Project_Orion_(nuclear_propu...

https://en.wikipedia.org/wiki/Interstellar_ark

Arguably if you launched the project Orion interstellar ark from the ground you could have pulled the world ending at the same time as well, perfect tripple combo. ;-)

This doesn't sound true given what we know about asymmetric warfare in general. What if we discovered the object really was an artillery shell sent to destroy us, but the civilization at the other end only has the resources to fire one every ten years with an accuracy of 1% to hit the Earth?

We might be like a primitive tribe facing an attacker with battleships - a technology that might as well be magic, but still one we can adapt to by abandoning the seafront village and retreating into the jungle.

> our current level of technology is already adequate to obliterate all life on the surface of the Earth

FWIW, and reinforcing your point, this is not even remotely true. Humans lack the technology now or in the foreseeable future to destroy the Earth’s biosphere, which would likely require boiling the oceans. There’s a reason we use that as an example of an impossibly large task.

> The rocket equation is a harsh mistress.

Nice Heinlein reference

Because humans are nearly incapable of projecting in a non-linear way. As in, it takes active educated effort. Most predictions you will see are linear extrapolations of what we already know. That's why flying cars were a popular "futuristic" scenario. They can drive now, why shouldn't they be able to fly in 50 years from now? That thought was prevalent in the 60s.

How should they even know that cars will become globally connected smartphones on wheels first? Smartphones didn't exist. The microchip didn't exist yet. The Internet didnt exist yet. It is impossible to make this combination from the 1960s perspective.

Complex non-linear systems don't work in intuitive ways and minor changes in fundamental variables can chaotically change the system in entirely unexpected ways. Non-linear developments will always be surprising, it doesn't matter how many Youtube videos certain pop scientists are creating.

This was a (minor?) plot point in Crichton's "Sphere".

Paraphrasing: if a smart bacterium steps on the battery of one of our space probes and gets destroyed by the heat, the smart bacteria community may think the aliens (we, humans) sent it to them for unfathomable reasons, perhaps to teach them a lesson, but we didn't think of them at all.

This isn't really that important. I don't care if the probe is here because of magh'Kveh or because its creators are really motivated to zzzzssszsezesszzesz. What I care about is whether it's going to be benign (which includes just cruising through doing nothing) or malevolent to me. I don't even care if the aliens think they are doing us a favor by coming to a screeching halt, going full-bore at Earth, and converting our ecosystem into a completely different one that they think is "better" for whatever reason. However gurgurvivick that makes them feel, I'm going to classify that as a malign act and take appropriate action... because what else can I even do?

And from that perspective, "benign" and "malign" aren't that hard to pick up on. They are relative to humanity, and there is nothing wrong with that. In fact it would be pathological to not care about how the intentions are relative to their effect on humanity.

Whatever happens, it's not like we can actually cause an interstellar incident at this phase of our development. Anything that they would interpret as an interstellar incident they were going to anyhow (e.g. "how dare you prevent our probe from eliminating your species?") and that responsibility is on them, not us. You can't blame a toddler that can barely tie their shoelaces for international incidents, likewise for us and interstellar incidents.

> It’s possible any alien life experiences complexities were fundamentally unable to comprehend

Possible. But I’d argue unlikely. We can’t make many assumptions about alien life, generally. We can about a technological civilisation that sends out interstellar probes.

Sort of the impetus (which at least gives us a reason unlike the movie adaptation Edge of Tomorrow but is not as important as the impact) in the novella All You Need is Kill.

We don't even need good sci-fi to explore that idea. We brush against it every day with ChatGPT.