Some thoughts on the Fermi paradox

[KathTheDragon]

That doesn't answer the question. What does this allow you to do that the two envelopes can't?

The contents of the envelopes are determined by prior physical causes. The states of the particles are a heavenly miracle.

Late, but this depends on which interpretation you follow. Contrary to popular belief, hidden-variables interpretations can and do work.

[Moose-tache]

PS. Even if it's just an SOS message, it has to be such that the intended recipient can't mistake it for a natural radio emission. If they can't mistake it, then why can we?

Because they already know what it is! We are assuming that the vast gulf in what is considered meaningful between different species from different ecosystems is trivial to recognizing an artificial signal. I don't think that is a wise assumption to make.

[Moose-tache]

I wish cargo were coming to earth that would render irrelevant any climate crises headed our way. I would be willing to work in order to manufacture whatever goods were wanted in return.

"Alpha Centauri is willing to send us the tools we need to stop climate change."
"What do they want in return?"
"Solar panels."
"Alright. Let's burn more coal so we can make the solar panels to send to Alpha Centauri so they will... Wait."
"What?"
"I feel like there's an easier way."
"Yeah, I think I see it too."
"We should broadcast a distress signal at 50 megawatts asking for green energy solutions."
"That will be expensive."
"You're right. Better burn more oil to pay for it."
"Good plan. Say, do you ever wonder if maybe we're idiots?"

[keenir]

I feel like I'm starting to repeat myself, so I'll let it go after this. This "weird obsession" is what our current global civilization is doing. It's more efficient to direct your energy rather than toss most of it into space. I don't really see why these things are hard to understand.

A "galactic civilization that doesn't know who its neighbors are" is possible, but also making it so that it depends for its survival on random SOSes is a couple weirdnesses too much for me.

I'm not assuming ignorance of neighboring habitats for no reason. They are separated by light years. Assuming FTL doesn't exist, I don't understand how they can possibly have direct knowledge of what's going on out there.

so, they haven't been sending messages to and from other habitats or nodes in between the time they left & the time they need help?

Directed messages are possible on earth because we have entered a relatively stable period, and we know the destinations of our messages. Imagine a medieval society. If a farmer leaves to visit the city, it is not inconceivable that he will never return, but they keep doing it anyway.

In that society, maps may not even exist. At each location, the farmer joins the throng heading to their common destination. My scenario is not even as bad as average pre-modernity. Which of my assumptions are fantastic?

except that the throne will be following a road to that city, even if the road does not stretch all the way to that farmer's door - it will still not be a trackless void.

and you're not talking about sending out a farmer, in your analogy.....sending an SOS out in all directions, is basically sending out a farmer in every direction from his home....and hoping and praying that at least one reaches a city without first dying of exhaustion because signals get weaker with distance, when not focused in one direction.

It won't seem that way to the people living there when cargo is constantly entering and leaving. I wish cargo were coming to earth that would render irrelevant any climate crises headed our way. I would be willing to work in order to manufacture whatever goods were wanted in return.

if goods are constantly entering and leaving, then by definition, their location is not unknown.

[keenir]

We know that dolphin communications are ordered. Researchers were working on it a few years ago.

researchers work on a lot of things...dolphin communication, tree telepathy, lysenkoism, etc.

PPS. Technically, I suppose they could also communicate by handing each other substances or objects. The point is, that would kill the range of that form of communication. Galactic civilizations are the kind of life we're looking for, not seed pods communicating by chemical cues.

why do they need your sort of range? they could advance from handing scented waxes, to packaging the waxes and shipping it to the recipient.

[keenir]

2) Notice that I said "human-like" intelligent life. If 90% of the life in the universe is some form of self-replicating plasma crystal, then they may not use a form of communication that we're even on the lookout for at all.

I would be more worried about false positives than false negatives. The method we use to analyze the artificiality of radio signals is based on entropy. Apparently, there is a physically reductive definition of what "order" signifies. There is no reason to think that would change for other forms of life. The worries come from the other direction. We once thought pulsar transmissions were from aliens. The presence of order is not sufficient to infer life.

1) We're just not looking hard enough. There are a lot of frequencies to check and the sky is very large. Maybe we're getting 24/7 alien TV but we haven't noticed cause it's coming in from directly above the south pole on some obscure frequency band nobody's checking.

Our data comes from space telescopes. Do you know specifics about what directions they are pointed at?

every direction...look at projects like TESS and its like.

[Ares Land]

WRT the Fermi Paradox. The point is not really that broadcasting is implausible. (For one thing, on a planetary scale it's dirt cheap, which is an argument in its favor)
The point is, rather, that back when SETI got started, it was assumed that any advanced civilization would give off a detactable radio signature for its entire lifetime.
It was really surprising not to detect anything... But now we know that an advanced civilization may very well move from technology that massively uses broadcast radio to one with methods of communications that aren't so detectable.

Although it's conceivable that a civilization might use broadcast at one stage or another of its history, it turns out it's not necessarily a given, will probably vary over the civilizations' life time and we can't really conclude anything about the absence of radio signals.

For that matter, SETI mostly checks microwave bands; other, more convenient frequencies are also checked, but they're covered by background noise a lot more. If the Zeta Reticulans are into long wave radio (awfully practical on a planetary scale), the signal to noise ratio for a source 40 ly away is awfully low.

[keenir]

WRT the Fermi Paradox. The point is not really that broadcasting is implausible. (For one thing, on a planetary scale it's dirt cheap, which is an argument in its favor)

I think one of the suggested answers for Fermi was, actually, that everyone is listening, and nobody is broadcasting.

[Vardelm]

I think one of the suggested answers for Fermi was, actually, that everyone is listening, and nobody is broadcasting.

The universe is filled with introverts.

[rotting bones]

Late, but this depends on which interpretation you follow. Contrary to popular belief, hidden-variables interpretations can and do work.

https://www.youtube.com/watch?v=cOe-7GH83Us

AIUI none of the interpretations change the practical implications.

Because they already know what it is! We are assuming that the vast gulf in what is considered meaningful between different species from different ecosystems is trivial to recognizing an artificial signal. I don't think that is a wise assumption to make.

There are many natural radio sources in the galaxy. I'm just not seeing how you can get away with SOS signals that don't stand out.

There is no reason for the real world analogy to be as ordered as a galactic SOS needs to be, but even the Morse code is ...---...

IIRC, entropy = -log(probability of occurrence)

You don't go with a bird call unless your recipient is expecting one at that moment.

"Alpha Centauri is willing to send us the tools we need to stop climate change."
"What do they want in return?"
"Solar panels."
"Alright. Let's burn more coal so we can make the solar panels to send to Alpha Centauri so they will... Wait."
"What?"
"I feel like there's an easier way."
"Yeah, I think I see it too."
"We should broadcast a distress signal at 50 megawatts asking for green energy solutions."
"That will be expensive."
"You're right. Better burn more oil to pay for it."
"Good plan. Say, do you ever wonder if maybe we're idiots?"

Looks to me like we're headed straight for cataclysm without even making the necessary number of solar cells. If they're idiots, what are we?

Avoiding climate change is a different goal from rendering climate crises irrelevant.

so, they haven't been sending messages to and from other habitats or nodes in between the time they left & the time they need help?

I think you misunderstand the theory of relativity. (Edit: Basically, there is no method to transmit any signal faster than the speed of light.)

except that the throne will be following a road to that city, even if the road does not stretch all the way to that farmer's door - it will still not be a trackless void.

Do you mean tracks leading in all directions? My mother came home from college in Siuri by taking a bus most of the way, and then crossing cultivated fields, walking along canals and fording rivers. Once, she was stuck because it had rained and the river looked dangerous. She waited on the bank till a bullock cart gave her a lift.

and you're not talking about sending out a farmer, in your analogy.....sending an SOS out in all directions, is basically sending out a farmer in every direction from his home....and hoping and praying that at least one reaches a city without first dying of exhaustion because signals get weaker with distance, when not focused in one direction.

That is not the analogy. The analogy is with the exchange network. In this context, the equivalent of a track would be the destination as seen through a telescope and the throng would be a convoy.

if goods are constantly entering and leaving, then by definition, their location is not unknown.

If relativity is true, then there is nothing to prevent us from receiving cargo from defunct habitats. If the sun is somehow snatched away by aliens, we will see nothing out of the ordinary and continue to orbit a nonexistent star for 8 minutes 20 seconds afterwards.

Once again, my point is that they don't know the locations of the habitats. This could be because of new habitats, moved habitats or extinct habitats.

researchers work on a lot of things...dolphin communication, tree telepathy, lysenkoism, etc.

Speaking for myself, being a scientist has nothing to do with anything. All that matters is the weight of your evidence and the solidity of your inferences. Eg. It may be that I would be better off by submitting to the authority of Taleb's grandmother than by listening to science, but frankly, I don't care about that. Rationality is more important to me than success.

why do they need your sort of range? they could advance from handing scented waxes, to packaging the waxes and shipping it to the recipient.

The idea that they will ever make it out of the wilds sounds like an overly optimistic assessment to me. That is a grossly inefficient form of communication in terms of range, time and resource expenditure. If a predator is approaching, you have to get back to your tribe and hand the first individual a scented wax. The entire tribe will then have to finish handing each other scented waxes, depleting who knows how much nutrition. Over galactic distances, material signs will of course be slower than light speed without FTL.

every direction...look at projects like TESS and its like.

Thanks. Just making sure, given dɮ the phoneme's posts.

Although it's conceivable that a civilization might use broadcast at one stage or another of its history, it turns out it's not necessarily a given, will probably vary over the civilizations' life time and we can't really conclude anything about the absence of radio signals.

The problem is that there is no sign of ordered signals anywhere across the universe. We've seen plenty of anomalies that point to holes in our cosmological models, but none of them credibly point to intelligent life.

I think one of the suggested answers for Fermi was, actually, that everyone is listening, and nobody is broadcasting.

The universe is filled with introverts.

Or it's Liu Cixin's Dark Forest analogy.

[Richard W]

There are many natural radio sources in the galaxy. I'm just not seeing how you can get away with SOS signals that don't stand out.

The SOS emitters come from an originally common culture, do they not? The SOS message could contain an element that identifies it as an SOS signal to those in the know, but is (unintentionally?) undetectable by those who do not know the convention. The principle is related to LPI radars.

[rotting bones]

The SOS emitters come from an originally common culture, do they not? The SOS message could contain an element that identifies it as an SOS signal to those in the know, but is (unintentionally?) undetectable by those who do not know the convention. The principle is related to LPI radars.

What is the mechanism you are envisioning?

1. If you are, eg, changing the frequencies of your transmission, you can detect them because you know what those frequencies are. But if your intention is to transmit to someone else, then they will also have to know the frequencies of your transmission. I'm not clear on how that would work.

2. These transmissions should still stand out from natural emissions if you want them to be detected by a second party.

3. Are you assuming an intergalactic war that makes such measures necessary? A war might be easier to detect than a radio transmission.

PS. The problem with war is the question of what other systems could possibly want from us. And if it's a Dark Forest, then at least the predator should be eager to transmit.

[Richard W]

The SOS emitters come from an originally common culture, do they not? The SOS message could contain an element that identifies it as an SOS signal to those in the know, but is (unintentionally?) undetectable by those who do not know the convention. The principle is related to LPI radars.

What is the mechanism you are envisioning?

1. If you are, eg, changing the frequencies of your transmission, you can detect them because you know what those frequencies are. But if your intention is to transmit to someone else, then they will also have to know the frequencies of your transmission. I'm not clear on how that would work.

The 'common culture' includes such details.

2. These transmissions should still stand out from natural emissions if you want them to be detected by a second party.

They stand out by the specially tuned receiver - which depends on the agreed characteristics of the signal.

3. Are you assuming an intergalactic war that makes such measures necessary? A war might be easier to detect than a radio transmission.

My first thought for the mechanism is power reduction or ease of scanning. I'm not entirely sold on the idea of 'distress' signals - a distress signal is an invitation to predators or scavengers. This is partly a Dark Forest viewpoint, but LPI can be an unintended effect.

PS. The problem with war is the question of what other systems could possibly want from us. And if it's a Dark Forest, then at least the predator should be eager to transmit.

The whole SOS notion seems to be based on an expanding system. Competition for asteroids could be a very good reason for war.

[keenir]

2. These transmissions should still stand out from natural emissions if you want them to be detected by a second party.

i thought you wanted them detectable by the rest of their galactic civilization.

please stop moving goalposts.

[keenir]

so, they haven't been sending messages to and from other habitats or nodes in between the time they left & the time they need help?

I think you misunderstand the theory of relativity. (Edit: Basically, there is no method to transmit any signal faster than the speed of light.)

and you're misunderstanding the nature of communication.

I can have a penpal that I write to all the time, back and forth, across entire continents......whether I'm writing the letters now with UPS or in the Victorian age with steam boats, relativity and plate tectonics (etc) don't matter if you're going back and forth between two points.

even if my penpal suddenly sends me a letter saying CALL THE POLICE, relativity isn't the problem in getting the cops mobilized to penpal's place.

except that the throne will be following a road to that city, even if the road does not stretch all the way to that farmer's door - it will still not be a trackless void.

Do you mean tracks leading in all directions? My mother came home from college in Siuri by taking a bus most of the way, and then crossing cultivated fields, walking along canals and fording rivers. Once, she was stuck because it had rained and the river looked dangerous. She waited on the bank till a bullock cart gave her a lift.

and thats a nice story, but what relevance does it have?

bus travel + canal pathway + river fording site....again, none of that is a trackless void you'd need to send out screams in all directions....even the cultivated fields by definition can't be trackless.

if goods are constantly entering and leaving, then by definition, their location is not unknown.

If relativity is true, then there is nothing to prevent us from receiving cargo from defunct habitats. If the sun is somehow snatched away by aliens, we will see nothing out of the ordinary and continue to orbit a nonexistent star for 8 minutes 20 seconds afterwards.

Once again, my point is that they don't know the locations of the habitats. This could be because of new habitats, moved habitats or extinct habitats.

then your "galactic civilization" ceases to exist as soon as its first two habitats are out of eyeshot of one another, because they never figured out how to keep track of one another (or to calculate trajectories)

why do they need your sort of range? they could advance from handing scented waxes, to packaging the waxes and shipping it to the recipient.

The idea that they will ever make it out of the wilds sounds like an overly optimistic assessment to me. That is a grossly inefficient form of communication in terms of range, time and resource expenditure.

so are social skills, to those of us who don't have them.

If a predator is approaching, you have to get back to your tribe and hand the first individual a scented wax. The entire tribe will then have to finish handing each other scented waxes, depleting who knows how much nutrition. Over galactic distances, material signs will of course be slower than light speed without FTL.

and you keep saying that relativity makes even that moot.

[rotting bones]

The 'common culture' includes such details.

They stand out by the specially tuned receiver - which depends on the agreed characteristics of the signal.

But unlike a radar, all of the message has to be pointed towards each destination. So we should still capture all of it. And if the frequencies are themselves in an ordered sequence, we might even take a crack at decoding it in time.

The best I can imagine is a transmitter that deliberately looks like, say, a pulsar, but has an undercurrent in its signal which, when analyzed, reveals the message. That sounds expensive to me. Let me know if you're thinking of something else.

My first thought for the mechanism is power reduction or ease of scanning. I'm not entirely sold on the idea of 'distress' signals - a distress signal is an invitation to predators or scavengers. This is partly a Dark Forest viewpoint, but LPI can be an unintended effect.

But detecting a camouflaged signal should normally consume more power.

The whole SOS notion seems to be based on an expanding system. Competition for asteroids could be a very good reason for war.

Uninhabited systems have asteroids too. Why waste resources on a war? (Edit: Of course, this assumes the galaxy is as uninhabited as it looks.)

i thought you wanted them detectable by the rest of their galactic civilization.

please stop moving goalposts.

If they are detectable by a civilization, they must be detectable by at least one second party. If I'm moving goalposts, which I am not, it is to make things more difficult for me.

[rotting bones]

and you're misunderstanding the nature of communication.

I can have a penpal that I write to all the time, back and forth, across entire continents......whether I'm writing the letters now with UPS or in the Victorian age with steam boats, relativity and plate tectonics (etc) don't matter if you're going back and forth between two points.

even if my penpal suddenly sends me a letter saying CALL THE POLICE, relativity isn't the problem in getting the cops mobilized to penpal's place.

I posted papers that show my proposal working the way I claimed in a different context.

and thats a nice story, but what relevance does it have?

Knowledge of the destination comes from elsewhere.

bus travel + canal pathway + river fording site....again, none of that is a trackless void you'd need to send out screams in all directions....even the cultivated fields by definition can't be trackless.

I have no idea what you are talking about. These are just as trackless as the galaxy.

then your "galactic civilization" ceases to exist as soon as its first two habitats are out of eyeshot of one another, because they never figured out how to keep track of one another (or to calculate trajectories)

Again, I posted papers showing how it would work.

so are social skills, to those of us who don't have them.

... Are you getting mad at me?

PS. There are some anomalies that could be because of alien civilizations. IIRC there is one star that appears to be full of radioactive waste that doesn't usually occur in nature.

[Richard W]

The 'common culture' includes such details.

They stand out by the specially tuned receiver - which depends on the agreed characteristics of the signal.

But unlike a radar, all of the message has to be pointed towards each destination. So we should still capture all of it. And if the frequencies are themselves in an ordered sequence, we might even take a crack at decoding it in time.

The best I can imagine is a transmitter that deliberately looks like, say, a pulsar, but has an undercurrent in its signal which, when analyzed, reveals the message. That sounds expensive to me. Let me know if you're thinking of something else.

Well, I had been thinking in terms of FM rather than AM. However, the key point lies in error-correcting codes. As the length of the message is not very long, by repeating the message and using a suitable error correcting code, one can drastically reduce the signal level needed to get the message through. The key to detecting such a message is to know what code to apply. If one thinks of the signal as string of 1's and 0's, reading them correctly a random 50.1% of the time is good enough to get the message through.

My first thought for the mechanism is power reduction or ease of scanning. I'm not entirely sold on the idea of 'distress' signals - a distress signal is an invitation to predators or scavengers. This is partly a Dark Forest viewpoint, but LPI can be an unintended effect.

But detecting a camouflaged signal should normally consume more power.

The power constraints lie at the transmitter end, not the receiver end.

The whole SOS notion seems to be based on an expanding system. Competition for asteroids could be a very good reason for war.

Uninhabited systems have asteroids too. Why waste resources on a war? (Edit: Of course, this assumes the galaxy is as uninhabited as it looks.)

I have been pondering whether one could develop asteroids by smashing planetesimals. Stealing someone's harvest can be an inviting option. There are probably better ways of aggregating and separating metals.

With your civilisation - more swidden-farmer-like than nomad-like, I suspect one would see rapid expansion through suitable regions. But perhaps the long-term resource areas will be molecular clouds - which should be good for attenuating signals!

i thought you wanted them detectable by the rest of their galactic civilization.

please stop moving goalposts.

If they are detectable by a civilization, they must be detectable by at least one second party. If I'm moving goalposts, which I am not, it is to make things more difficult for me.

But you're only requiring the civilisation to make contact with its far-flung members. 'Secret' signs could work well, but the coding is only needed to reduce the transmit power required.

[Richard W]

I can have a penpal that I write to all the time, back and forth, across entire continents......whether I'm writing the letters now with UPS or in the Victorian age with steam boats, relativity and plate tectonics (etc) don't matter if you're going back and forth between two points.

What if you're trying to keep in touch with Dr Livingstone while he's on his travels?

This SOS-using civilisation sounds as though it's flitting from star to star. That is not the stay-at-home mode we considered earlier. I think the question is, "How long will it be before they're here?". Or may be our system hasn't been worth having since Jupiter cleaned up the inner solar system.

[keenir]

and you're misunderstanding the nature of communication.

I can have a penpal that I write to all the time, back and forth, across entire continents......whether I'm writing the letters now with UPS or in the Victorian age with steam boats, relativity and plate tectonics (etc) don't matter if you're going back and forth between two points.

even if my penpal suddenly sends me a letter saying CALL THE POLICE, relativity isn't the problem in getting the cops mobilized to penpal's place.

I posted papers that show my proposal working the way I claimed in a different context.

?

and thats a nice story, but what relevance does it have?

Knowledge of the destination comes from elsewhere.

*sigh* are you referring to SETI searches for the galactic civilization, or are you talking about a galactic civilization's habitat that suddenly forgets where its been sending its shipments and getting deliveries from?

the two are not the same.

bus travel + canal pathway + river fording site....again, none of that is a trackless void you'd need to send out screams in all directions....even the cultivated fields by definition can't be trackless.

I have no idea what you are talking about. These are just as trackless as the galaxy.

okay, if you're going to use magic to have seeds appear from nothing and rain into the ground without using farmers or farm equipment, please say so, because otherwise there can and will be tracks and trails used by the equipment and-or the farmers to plant, weed, and harvest.

then your "galactic civilization" ceases to exist as soon as its first two habitats are out of eyeshot of one another, because they never figured out how to keep track of one another (or to calculate trajectories)

Again, I posted papers showing how it would work.

where?

so are social skills, to those of us who don't have them.

... Are you getting mad at me?

no, I'm pointing out that I - like others - do not have the same presumptions you seem to have.