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Comment by usmannk | Hacker News Reader

> Maybe something is out there, but out of reach, or deliberately silent?

Have you read The Three Body Problem series by Cixin Liu? It's a terrific (and recently quite famous + awarded) sci fi trilogy that explores this idea. That all sufficiently advanced civilizations have learned to be extremely radio silent in order to escape detection. Reason being that they all eventually conclude that, from a game theoretic standpoint, the only reasonable thing to do when you detect another civilization is to eliminate them before they do you.

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The problem I see with this idea is that it depends on either FTL travel, or on a horizon of time much larger than I would imagine. If we were discovered by a war-like civilization in one of the nearer stars today, it may well take them hundreds or thousanfs of years to get here even with a probe. Is it really a plausible threat?

This is exactly the scenario in the books ;)

Those book's are absolutely great, the 2-D probes pack t to 3-D..ah man have to read them again!!

When malicious eavesdroppers are involved, some fates are worse than death...

http://freefall.purrsia.com/ff400/fv00307.htm#anunsecuredlin...

Others like Vernor Vinge have speculated that the galactic net has really bad malware.

This assumes that alien civilizations purely see us as competition and not an organism they can achieve synergy with.

What if organisms could choose other ways of allying and joining together? What if, say, you had the strong, dominant, ambitious sub-population of a race trying to ally with other strong, dominant, ambitious life forms without thought to race? What if the organisms in the universe which favored peace decided to seek each other out and unite for a common cause?

They definitely could choose. The problem is: communication. Light speed, although fast, isn't fast enough for communication between vast distances. How can you establish any sort of trust when messages take decades/centuries to deliver? It'd simply be safest to expect the worst.

> What if organisms could choose other ways of allying and joining together? What if, say, you had the strong, dominant, ambitious sub-population of a race trying to ally with other strong, dominant, ambitious life forms without thought to race? What if the organisms in the universe which favored peace decided to seek each other out and unite for a common cause?

That could be true.

Judging by history, that's not a very good bet. Peace sort of works among humans, in part because we are so close genetically. But Pre-WWI Europe showed that you can't engineer peace even by inter-marrying rulers.

Stepping away from humans a small amount, even today people regularly eat primates of various sorts (i.e. "bush meat").

Why do you think humans would ever make peace with alien cultures?

> Why do you think humans would ever make peace with alien cultures?

Great question. Maybe we need interstellar mutually-assured destruction. Seems to be the only thing, short of dominance, that has worked to preserve peace(-ish).

> Maybe we need interstellar mutually-assured destruction. Seems to be the only thing, short of dominance, that has worked to preserve peace(-ish).

It seems unlikely to me that when 2 alien cultures meet, that their technology levels are so similar that MAD is possible.

It might not need to be about technology, but biology, à la War Of The Worlds.

Whilst I doubt that (all of?) our viruses would have any effect on them (as they require our own cells to reproduce - aliens are unlikely to have a similar makeup), but things like funguses and bacteria could be very very bad for them.

Seems fairly unlikely though.

Random bacteria and fungii that are introduced to humans don't kill us all off. Bacteria especially are everywhere, it stands to reason that over all of the exploring, investigating and just plain spreading that we do, we'd encounter some bacteria that are new to a population. If those had any great chance of killing us off, shouldn't at least local examples exist of that happening?

Instead I think what we see are the organisms that affect us are those that coevolve with either us or with related species. We're killed by the things we spend a lot of time with, not random out-of-context bacteria that's never seen a mammal before.

If that's true of us, seems hard to say why it wouldn't be true of aliens, no?

> We're killed by the things we spend a lot of time with, not random out-of-context bacteria that's never seen a mammal before.

We're mostly killed by things that have never been in humans before because we haven't developed defenses. Sure, most of those things don't kill us, but you really only need the right one to come along and basically wipe us out. Part of the reasons we're ultimately able to develop a defense is because it is Earth life and we've seen all the tricks. Any alien microbe that is able to establish itself inside our bodies might not have to worry about any of our defenses.

I think you've really got the wrong model. Think of the introduction of non-native species to various ecosystems. A lot of the time, the non-native species either can't hack it, or they find an equilibrium. But some of the time you get kudzu or eurasian watermilfoil.

In any case, the point is largely moot. Any civilization we are likely to meet in the next thousands of years will necessarily have to visit us and if they can do that, they can just lob a couple space rocks at Earth and wipe us out from a distance.

> it stands to reason that over all of the exploring, investigating and just plain spreading that we do, we'd encounter some bacteria that are new to a population. If those had any great chance of killing us off, shouldn't at least local examples exist of that happening?

We have examples of exactly this! It was very bad: https://en.wikipedia.org/wiki/Native_American_disease_and_ep...

Those were diseases already in humans moving to an untouched population of humans, not what I was talking about.

A bacterium that hasn't seem humans before is pretty unlikely to be able to do anything to us. One that hasn't even been in mammals before is even less likely, etc.

https://en.wikipedia.org/wiki/To_Serve_Man_(The_Twilight_Zon...

this is where i lost interest in the book. the idea that destroying another civilization is the only reasonable choice is beyond ridiculous.

first of all, game theory is based on our current experience and conditioning. if we raise a society where cooperation is valued, then the outcomes of game theory will change too. it is absurd to assume that game theory is universal.

but even if it were, and we'd have to assume that all aliens are hostile, the recources necessary to mount an expedition to another inhabited solar system are much larger than the benefits of exploiting a remote planet. it's simply not worth it.

what would be the point?

my expectation is that before we are able to send ships we'll be communicating for a long period, giving us enough time to share scientific discoveries.

i'll even go as far as to claim that developing space travel that can take us to another inhabited solar system will only happen in collaboration with the civilization that we want to visit.

Probably in universe time, equivalent intelligent civilizations will only be using radio waves for communication for maybe few hundred years. To be able to find radio signal from another civ in that window of time is unlikely. A more advanced Comm method is used.

In this series they move on to gravitational waves.

I have not, I will definitely check that out, thanks for sharing. I feel that SETI is something I'm woefully uneducated on, and can't find good places to jump into research before sources seem to go wildly off the rails.

Yeah I can testify that it's one of the best Sci-Fi novels these years. I read the original Chinese version but I heard that the translation of 1st and 3rd book (by same person) is excellent.

Wouldn't someone send communication signals to lure or bait other civilizations? For example, spam a friendly hello message on every potential communication channel and encourage new civilizations to reply. When they do, destroy them.

No, because that'd just be endangering your own civilization unnecessarily. There's always a bigger, badder civ out there :)

But earth debunks that theory, no body came to destroy us yet.

Maybe they're still on the way. We didn't start radio broadcasts until quite recently ago.

We can't send a strong enough radio signal to be detectable at any other nearby stars

The Three Body Problem is great, but it assumes the existence of weapons of ludicrous destructive power.. The only other time I've ever seen a piece of fiction where someone had that amount of destructive power was in a cartoon. (And even then I only saw it once)

If you assume that there's no faster-than-light space travel, it doesn't really make any sense to engage in interstellar conflict IMO. The same tech that would let you travel between the stars would also let you live in comfortable artificial habitats around your own home star, close enough to the rest of your civilization to be able to watch TV and keep up with HackerNews.

how detectable would the EMP from nuclear explosions be? Obviously that is strong, but not very directed..

You do realize that there is gigantic nuclear reactor sitting about 93 million miles from where you are right now, right? An energy source so massive, it would only take a small fraction of it to heat and power several full planets. It would be like billions of nuclear explosions every second.

The Sun dwarfs anything we can do on Earth. Any arbitrary explosion of that sort wouldn't even register as noise next to the Sun. Our radio transmissions are directed and deliberate in a way that is noticeable even among the noise. Like watching scrambled HBO on an old cable box.

Yes. However I don't know if that is different. That is a roaring fire, whereas the https://en.wikipedia.org/wiki/Tsar_Bomba was a 58 megaton event which would have created a pulse. Electronic devices can sit in the sunshine all day, exposed to the roaring fire of the sun but a singular EMP can take them out? When you look for things, you look for what is different to its surroundings. Even when our own people are looking for planets around other stars, they are looking for an incredibly small change. They found something nearly 30,000 light years away like that.

Yes, we're close enough to Earth that it has a lot more affect on us than the Sun. And the Earth has a magnetic shield. Etc.

The Tsar Bomba did not destroy all life on the planet, did it? A simple solar flare is 5 to 10 magnitudes larger. Yes, small changes, but small changes that don't belong.

We are close enough to the Sun that even if that were detectable at the scale of the cosmos, the distance between the Earth and the Sun is a rounding error at the scales we are talking about.

Appreciate this. We are effectively in the Sun's atmosphere. The entire solar system is. Scale matters.

> The Three Body Problem is great, but it assumes the existence of weapons of ludicrous destructive power.. The only other time I've ever seen a piece of fiction where someone had that amount of destructive power was in a cartoon. (And even then I only saw it once)

That part doesn't seem to hard to me. A robotic spacecraft could install solar sales on a comet in such a way as to crash it into the target planet a few hundred years later. This could go unnoticed until it was too late by the target planet. Alternatively, a beam-powered probe (e.g. 'starwisp' or similar) moving at relativistic speeds could be crashed into the target planet.

Neither of these require cartoon physics.

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