Everything that travels via a wave (wifi, gsm, radio, tv, etc) travels in more or less planar dimension. in order to stop it, you'd have to have some kind of wave blocking shutter (physical requirements for such a block would depend on the length of the waves you want to block) around the whole planet. Blocking waves is not feasible as long as we want to have sun
The dangers of Active SETI are based on a lot of human-centric assumptions.
Any hypothetical alien civilisation advanced enough to pose a threat may see our radio broadcasts and space probes as being so crude that they consider us too harmless to bother with.
If there are actively “xenocidal” aliens out there they may also have far more effective ways of detecting their targets.
Disagree. The counterargument is simple - space is large and time is long. We aren't a threat now but we could easily become a threat in, say, 1000 years. Which, is basically no time at all in interstellar politics. Any species who could potentially become a technical capable threat should be assumed as a technically capable threat.
The Dark Forest theory is something that makes for a scary sci-fi novel, but it isn't really plausible in the real world. One of the major reasons is that individually doing atmospheric analysis for every planet in the galaxy actually is an entirely possible task, especially for a civilization that's supposedly advanced enough and close-by enough to be able to destroy our civilization somehow. If advanced alien civilizations were present in our galaxy and had the philosophy of destroying potential competitors before they also become advanced then we should have been wiped out hundreds of millions of years ago already. We shouldn't exist under a Dark Forest scenario.
I know this is all hypothetical, but remember they may have the ability, but haven't reached the cultural moment, where they have the interest. That could be any random moment now or in the future too
If this is to be a Fermi paradox solution (which the Dark Forest is usually presented as) then it has to be universal. "Sometimes a civilization somewhere decides to kill a few potential rivals" isn't enough to explain why the universe appears to be silent.
A fair point, but even though we assume time and space are massive, there is an ordering to things.
There is a day before a civilization decides to kill it's neighbors, and a day after.
We can assume the state of things (big old space should have had that plot arc already) but we can't know if we are still in the opening episode, or before it.
Regarding general silence, agree that is not answered by my discussion. I personally lean more towards x factors disturbing our assumptions. (I.e. long running biospheres with zero advancement to radio age) but I increasingly wonder if we are just early to the party, as egotistical as that sounds. Imagine that the civilization that will one day rule the galaxy / universe is just now figuring out how to make a basic tool?
In Alastair Reynolds' Revelation Space series, the victors of a "dawn war" far in the galaxy's past were machines and they decided to wipe out any sentient life in the galaxy for reasons that aren't important here, but not life in general. But by the time we came around they had degraded to the point that they weren't doing a good job anymore and a few civilizations were just starting to slip out into space. Then they get detected and destroyed.
So the combination of wanting to destroy civilizations, but not all life and breaking down over time would allow it.
This is another example of a scary sci-fi novel needing a very specific set of circumstances to arise in order for the scary sci-fi novel's story to work. It isn't a plausible case to be basing any real-world decisions or science on.
It's like trying to have a serious discussion of vigilantism and the death penalty and someone brings up Freddy Krueger as the basis for their argument.
Here is my take on it. It all depends on if there is some sort of hard limit on how much we can accelerate an object with mass in space.
If we are capped at say, 25% of the speed of light we will most likely never meet our intragalactic neighbours. The times scales and distances involved are insurmountable and economically they would have no reason to attempt travel to another inhabited planet. The journey is too dangerous on many levels to be worth attempting. No reason to contact, no reason to fight, many closer resouces in our respective solar neighbourhoods that wont shoot missiles at us.
If we live in a universe that allows for FLT or even just 99.9999 percent of c then the alien overlords are already aware of us and are chill enough to leaves us be for the most part. So it really almost doesnt matter in my opinion.
I did love the 3 body problem trilogy, Liu Cixin is a master story teller.
then the alien overlords are already aware of us
Unless they have been actively and vigorously scouting for us with FTL travel, our earliest radio transmissions, even if we assume they're somehow still recognizable and not totally lost in the background noise of space, have only made it about 126 light years or so from earth (and honestly our very earliest ones probably wouldn't be recognizable from very far at all, Marconi's radio was of course pretty crude, it was our first time playing with radios, so we can probably chop a good 20+ light-years off of that easily if we're being realistic)
Now that encompasses some 60,000 or so stars, which is a tiny speck of the observable universe, and depending on how you fill out the Drake equation that could be a whole lot of aliens out there listening, or literally no one. And only about half of them, assuming no FTL travel or communication, would have had a chance to get a response to us by now (if they even wanted to) since their response would have to travel at or below C.
If they're in the Milky Way or nearby intergalactic space and have bothered to point instruments at us that are far beyond the capabilities we have on earth now today within the last 300,000 years, they may know that homo sapiens exist, but they'd need to be within 3000 light years to know that we entered the bronze age, and within about 200 to know that we've even started playing with electricity (and counting on them looking specifically at us is a real long-shot)
Parts of the Andromeda galaxy, at best, is maybe aware that Australopithecus evolved. Any further out and no one has any clue that anything really resembling humans at all is here.
Now that sort of isolation does give us a bit of security in case there is a xenocidal race that would like to wipe us out somewhere in the universe, unless we're very unlucky we probably have a long time before we have to worry about them even knowing we're here, and at least that long again until they can do anything about it (unless they do have FTL travel) so probably not something we actually need to be concerned about, again unless we get really unlucky the sun dying in a couple billion years is probably a more pressing concern.
But why would evil aliens wait for intelligence to evolve and be a potential threat when they could just destroy every biosphere before life can produce intelligence?
We can't really pretend to understand the thoughts or motivations of aliens, after all, they are completely alien to us.
A good point, and the fact that we dont see evidence of solarsystems being wiped out when we look into space makes me hopefull that super high intellegence is fundamentaly incompatible with agression
I think it's likely we're the first and oldest advanced civilization in the universe, which means we'll likely always have a technological advantage to the tune of 100+ thousand years head start. It's entirely plausible that we are the future's xenocidal species.
Our nearest intragalactic neighbors are no closer than 4.25 ly. We’re not going to get out of our solar system with a manned mission. You can forget about intergalactic.
Not with that attitude.
https://youtu.be/LlhHE2VA1ic?si=ZwN4S4uoaYkkZT55
Long story short, hiding in a universe with even slow interstellar travel is not a viable long term survival strategy. You're vastly underestimating the potential industrial capacity of even a single solar system.
Because it's sci-fi nonsense essentially.
Just because someone has a theory doesn't automatically mean we should live by it.
I mean this could all be a simulation so why bother living right?
What are you talking about?
He's talking about the risk of another civilization to learn that we exist, then come down here and wipe us out.
Not if we beat them to it first. Take that aliens!
He just read The Three Body Problem. It's the main plot point.
The big thing people over look when considering the we are broadcasting thousands od watts into space, they might hear use is SNR
Signal to noise ratio. (the more random stuff on a frequency the harder it is to read the signal)
Yes, humans are pumping out a huge amount of radio (etc) signals into space. it is not coherent or directed.
Thousands of antennae all over the world pumping different signals but from far away, they are all noise interfering with each other.
IIRC: Even if there was a radio telescope only a few light years away, all they would see pointing directly at earth would be static.
Not to mention the signal degrades, and the signals from the ww2 era have only reached 80 light years away. Any farther away and the signal has not reached them yet
Even then, the signal strength is not high enough. It gets overshadowed by the CMBR before it gets anywhere significant.
Had to come to the bottom of the thread to find the only take that matters. Talk of our signals being noticed is about unthinkable given the inverse square law.
Let's assume there is some advanced civilization that doesn't want competition and kills any aliens it finds. Would it make more sense for them to wait for an alien race to develop technology and be on the edge of being a threat before they take action, or would they just destroy the biosphere of any planet they find that could eventually evolve intelligence? My bet is they wouldn't wait around for a threat to appear, they would prevent it from forming in the first place. With that in mind, we are on the verge of being able to detect if nearby exoplanets could support life. A much more advanced race should be able to do this for every star in a wide area around it, if not the entire galaxy.
Earth has had life for about 3.7 BILLION years. It should have been detectable for most of that. The Milky Way is about 100,000 light years across which means an advanced civilization anywhere in our galaxy should have known that earth supports life for basically its entire existence.
So we are left with three possibilities: Advanced aliens exist and don't care Advanced aliens exist but are waiting for us to be a threat before doing anything Or advanced aliens don't exist.
I find option two to be very unlikely.
This isn't the only problem with dark forest theory though. If life is common enough that intelligence pops up everywhere and competition for resources ensues then no matter what kind of FTL travel you may or may not develop it is inevitable that you will eventually run into a civilization more advanced than you are. Unless you can instantly occupy the entire universe at once, someone somewhere will have been far enough away to develop more than you by the time you met then. In such a case you want to be seen as a nice neighbor, and not a locust, or you risk extermination.
As to your point of not being able to look for life across the galaxy from a single solar system, I think you vastly underestimate the power of technology. We already have plans for how to survey every star system in the galaxy. The telescopes required are just several orders of magnitude bigger than our current best. Making them would be an economics problem, not a physics or engineering problem. But if a race is at the point where they can destroy a biosphere from light years away they are necessarily at the point they can build those telescopes.
Option 4: Advanced aliens killed the dinosaurs, and they'll kill us once they notice us. But maybe they only check once each galactic year?
Option 5: Advanced aliens killed the dinosaurs, but their civilization fell into ruin.
Option 6. The dinosaurs destroyed the advanced aliens, but one rock got through and fatally damaged their society as well
Ha, I love it!
Given the size of the rock that killed the dinosaurs it seems pretty far fetched that aliens would have done that. It's too small. They would have had to specifically wanted to kill most life but not all of it. When you're talking about eliminating threats from interstellar distances you go with overkill. You hit somewhere hard enough to rip off the crust and make the planet molten again.
Now if you want to say aliens saw dinosaurs as a dead end path for evolution and hit the reset button that would at least make some sense.
Yeah, that's a fair point about using a larger meteor. Unless the alien assigned to the task screwed up? Unlikely, yes, but that's the problem with this kind of speculation. There isn't really any evidence to examine. Maybe there weren't any aliens. Maybe there were, and they screwed up! Maybe there were, and they thought what they used would be enough, but a quirk of Earth biology let small mammals survive. Maybe there were two groups of aliens, and the second group interfered enough to prevent full overkill.
Alien shepherds could def be Option 6. These could all be fun sci-fi story prompts!
Unless the alien assigned to the task screwed up? Unlikely
Able to detect life from a different solar system. Able to send a meteor to exactly hit a specific planet light years away. Yet they screwed up the math on the size?
I prefer the Jenkinsverse answer- That we are sadly the strongest species in the universe
There are some fun Kurzgesagt videos on this, for those that might be less familiar with the theory / discussion:
In the hope of proving intelligent life exists somewhere in the universe.
(Sorry. Feeling a bit cynical this morning.)
The real question here will be if a more advanced civilization would want to make contact with humankind, or if that advanced civilization would prefer to do abductions and experiments over humans to find a way to have humankind under control.
Why would they want to make contact instead of an undercover take over the planet?
Edit: TBH I have never understood the weird concept some people have about Aliens and UFOs, I mean about thinking they are chill dudes who will come here to exchange knowledge, pay some hookers and snort cocaine with us everything shine and good, but tbh I believe they are more the kind to make experiments with us and get humankind existence gone. Supposing they have the knowledge to get here I don't believe they would like to chill with the monkeys.
Because our civilization is not united. We're unable to coordinate and act as one being.
Because nobody reads Fred Saberhagen.
Recommended reading?
The Berserker series. Very classic military/hard SF.
Thanks
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