The Poll of the Seven Planets

[CavLancer]

He's not a model either.

 

[Glassfan]

Radio is actually not a bad way to communicate to as many nearby systems as possible. It gets through most of the gas and debris of the galaxy fairly well and would also be easily detectable by any civilization that had the capacity to even ask if life was out there..

Yes, in fact I recall reading the original Asimov paper on interstellar radio communication back when I was a kid, just as Drake was suggesting we watch the skies. The trouble with radio is that it's signal strength falls off at the inverse of the square of the distance. So it's very weak at the humble power levels we humans transmit at (as opposed to stars, galaxies and quasars). Furthermore, a civilization's "signal" is not heterodyned - it's just a bunch of noise - many thousands of different broadcasts muddled together - not a coherent signal.

Some of Drake's assumptions also appear to be wrong. He was writing (and thinking) that at a time (1950s & 60s) when the number of broadcast sources were skyrocketing - new AM, FM radio stations were opening up; television towers erecting, Cold War military bands, and telecommunication microwave broadcasts.

Since then, however, while there are indeed more "stations", these are increasing being transmitted by fiberoptic cables, and are not broadcasting into space at all. There are fewer military bands and these are now directional. The only significant increase in broadcast source are in cellphone towers, and these are very low-power.

It appears Professor Drake did not anticipate that technological advance would mitigate the radio waste product SETI depends on. Back in the day, Television stations used to send out thousands of kilowatts of energy to blanket an entire region in signal - most of that just radiating out into space. Now a station like ESPN sends just a few miliwatts over a cable.

He also did not anticipate modern environmentalism, which seeks to curb energy waste in all its' forms.

I would also point out that SETIs' fundamental assumption that advanced technological species will be peaceful, is almost certainly wrong. I expect that in any thousand or so extraterrestrial civilizations, only one has to be piratical to cause all the others to remain silent and not give away their positions. Out around 80 light years, they're probably thinking, "What's wrong with that Hitler fellow, broadcasting in the clear..."

 

[warpus]

I would also point out that SETIs' fundamental assumption that advanced technological species will be peaceful, is almost certainly wrong.

I agree. Any intelligent species out there would have been molded by the pressures of evolution. Meaning they got to the top of their food chain by being the top predator in some form or other, just like we did. Meaning that these instincts are a part of who they are.

I would assume any extraterrestial intelligence to be a danger, until proven otherwise.

 

[Sommerswerd]

I agree. Any intelligent species out there would have been molded by the pressures of evolution. Meaning they got to the top of their food chain by being the top predator in some form or other, just like we did. Meaning that these instincts are a part of who they are.

I would assume any extraterrestial intelligence to be a danger, until proven otherwise.

Exactly... right now, assuming they out-tech us... they are perfecting their warp ships... and having polls, about life on earth... hoping that we have life here that is suitable for them to make pets and eat but not advanced enough to stop their colonization plans. They've polluted their planet(s) beyond all use through rampant capitalism by now afterall... their only chance is to get here and start over with a healthy "new" world.

 

[hobbsyoyo]

Yes, in fact I recall reading the original Asimov paper on interstellar radio communication back when I was a kid, just as Drake was suggesting we watch the skies. The trouble with radio is that it's signal strength falls off at the inverse of the square of the distance. So it's very weak at the humble power levels we humans transmit at (as opposed to stars, galaxies and quasars). Furthermore, a civilization's "signal" is not heterodyned - it's just a bunch of noise - many thousands of different broadcasts muddled together - not a coherent signal.

Some of Drake's assumptions also appear to be wrong. He was writing (and thinking) that at a time (1950s & 60s) when the number of broadcast sources were skyrocketing - new AM, FM radio stations were opening up; television towers erecting, Cold War military bands, and telecommunication microwave broadcasts.

Since then, however, while there are indeed more "stations", these are increasing being transmitted by fiberoptic cables, and are not broadcasting into space at all. There are fewer military bands and these are now directional. The only significant increase in broadcast source are in cellphone towers, and these are very low-power.

It appears Professor Drake did not anticipate that technological advance would mitigate the radio waste product SETI depends on. Back in the day, Television stations used to send out thousands of kilowatts of energy to blanket an entire region in signal - most of that just radiating out into space. Now a station like ESPN sends just a few miliwatts over a cable.

He also did not anticipate modern environmentalism, which seeks to curb energy waste in all its' forms.

I would also point out that SETIs' fundamental assumption that advanced technological species will be peaceful, is almost certainly wrong. I expect that in any thousand or so extraterrestrial civilizations, only one has to be piratical to cause all the others to remain silent and not give away their positions. Out around 80 light years, they're probably thinking, "What's wrong with that Hitler fellow, broadcasting in the clear..."

(made up numbers warning)
All frequencies are affected by the inverse square relation if they aren't collected in lasers or cables of one form or another. That's not unique to radio waves. While you can get a much more powerful laser signal with an equivalent amount of power relative to radio waves there are drawbacks. I suspect that for a serious contact effort, you'd end up sinking almost as much resources into setting up a laser network to ping stars as you would an equivalent radio network. You'd need a lot more transmitters for sure given the directionality of lasers but in the end, I don't figure building a network of 150 GW power stations to feed a radio network would be all that much more resource intensive than a network of 50 GW stations for laser systems. Certainly relative to the size of the entire project, such matters amount to moving decimal places around unless I'm grossly mistaken in my estimation.(/made up numbers)

I don't assume most alien civilizations are peaceful but I do assume it is the default state.

I agree. Any intelligent species out there would have been molded by the pressures of evolution. Meaning they got to the top of their food chain by being the top predator in some form or other, just like we did. Meaning that these instincts are a part of who they are.

I would assume any extraterrestial intelligence to be a danger, until proven otherwise.

I don't know about this though. That assumes we know everything there is about how evolution works and all the types of circumstances that life can occur in. There can be entire ecosystems out there that are heavily biased against predation - there are probably systems that fly in the face of how things work on Earth.

 

[Glassfan]

I agree. Any intelligent species out there would have been molded by the pressures of evolution. Meaning they got to the top of their food chain by being the top predator in some form or other, just like we did. Meaning that these instincts are a part of who they are.

I would assume any extraterrestial intelligence to be a danger, until proven otherwise.

Hawkings and I largely agree.

Carnivores/Predators certainly have a step up on intelligence and inquiry. And they're HUNGRY!!!!!!!!!!!!

And again, If we're dealing with machine intelligence, all bets are off.

...I suspect that for a serious contact effort, you'd end up sinking almost as much resources into setting up a laser network to ping stars as you would an equivalent radio network...

So is SETI a waste of resources? 50 years of failure is hard to justify, except to say our first attempt at contact has been carried out and it's time to move on to stage two.

 

[hobbsyoyo]

Waste of resources? No if for no other reason than we wouldn't have known we wouldn't find anything if we didn't try looking. I'd be loathe to cancel it without making a serious commitment to a better effort and even then, an absence of findings doesn't prove an absence of signals. 50 years is not that long to be looking in the scheme of things.

But this question confuses the issue - there is a pretty big difference between passively listening to the stars and an active "let's bang on the universe and listen to it rattle" contact effort. What few intentional "hello" signals we've sent out have so far been pitiful compared to the task and don't in any way resemble a civilization-wide effort to contact aliens.

Does Hawking really believe most alien civilizations will be aggressive? Or does he just accept that it's inevitable at least some aliens will be aggressive and there's probably enough alien civilizations out there to be worried about this.


I think the latter is reasonable, the former much less so. I also think the more we try and quantify the odds of alien civilizations being hostile or peaceful, the more likely it is we will make the same kind of mistakes Drake did. Having said that, caution is prudent in my opinion.

 

[CavLancer]

Any way to detect the thousands of nukes we've set off?

 

[hobbsyoyo]

No across interstellar distances. The amount of fallout globally is minuscule (even if locally it's devastating) and would not really be detectable in our atmosphere by an alien civilization. For one thing, the radioactive by-products in our atmosphere are not in high enough concentrations to be detected in a spectrograph taken from light years away. For another, the radiation emitted itself is far too disperse and low power to be detected directly.

I guess you could build absolutely enormous detectors (read: planet sized) that could pick up the fallout in a spectrograph but it boggles my mind how large they would have to be. An alien civilization probably wouldn't build such a system until the had a known target to look at and by that point they would have picked up enough of our signals to be able to piece together the fact that we possess and have used nuclear weapons without having to build a special detector.

 

[red_elk]

Wouldn't flash of gamma radiation from nuclear explosion be detectable though?
From what I heard even usual radio transmissions can be detected by advanced civilization light years away. If there are some in ~100 ly from us, they most likely already know we exist. And this radio bubble we've created is inflating with the speed of light.

 

[Sommerswerd]

If our advanced alien overlords know we're nuke-launching fanatics... we're toast They'll be coming at us, armed to the teeth.

 

[warpus]

I don't know about this though. That assumes we know everything there is about how evolution works and all the types of circumstances that life can occur in. There can be entire ecosystems out there that are heavily biased against predation - there are probably systems that fly in the face of how things work on Earth.

The thing is that we only have this planet to investigate as a case study. So if our goal is to not make any assumptions, we have to assume that until proven otherwise, what we know about evolution what we've already learned. And as such this leads to certain conclusions, such as the ones I've made.

I agree that things could be different on other planets, but we have no idea how or in what way. It could be hypothetically possible to set up experiments using fruit flies (or other organisms) to study some of the potential effects you propose. So it would be possible to study, it seems, perhaps.

In the end though, without making any assumptions whatsoever, we have to assume that we better be careful when running into other intelligent life.

 

[Manfred Belheim]

Oh, I thought I read somewhere that any planet within (2017-1881=) 136 light years of us could know that we were an intelligent species b/c our radio broadcasts just keep travelling in an ever-expanding sphere outward indefinitely (and meaningful communications are distinguishable from noise). You all are of course right that if they've long ago moved entirely on to some non electro-magnetic mode of telecommunication (Future Tech), then we wouldn't be picking that up. I guess there's no way of knowing how deep into the future we'll abandon radio for something better. (Though there was a thread here about a year ago about how no human tech has gone utterly obsolete). And, yes, there's no way of knowing what the attitudes of a different intelligent species would be (wanting to keep undiscovered, rather than reaching out to their interstellar neighbors).

Well think how many radio and TV transmitters you have to have dotted all over the place in order for everyone to get a decent reception. If transmitters were powerful enough to be picked up light years away that wouldn't be necessary (line of sight considerations aside). True they can build bigger recievers, but the area of them would need to increase proportionately with distance to maintain signal strength, so you'd be talking the size of at least a planet at those distances, if not a Dyson sphere or something.

 

[Glassfan]

No across interstellar distances. The amount of fallout globally is minuscule ...

Wouldn't flash of gamma radiation from nuclear explosion be detectable though?

Red elk makes a valid point (sure, not fallout, but...) The actual x-ray flux and gamma radiation from our thermonuclear (fusion weapons) testing in the 1950s and 60s would be highly identifiable signals to extraterrestrials. Vast amounts of ionizing radiation are given off in a flash, though the actual radiation levels seem to be classified. Consider Castle Bravo or the Tsar Bomba.

In a nuclear war, the duration of the flashes would be mere days - but in a "Cold War" like we had on Earth, there would be a series of flashes over decades - representing a certain technological achievement (sic) level. I would think the flashes would be highly characteristic and revealing. They include a fission bomb precursor,and then the fusion detonation itself (one, TWO!), as well as a distinguishable energy signature.

SETI alone would be singularly unequipped to recognize these detonations.

 

[hobbsyoyo]

Wouldn't flash of gamma radiation from nuclear explosion be detectable though?
From what I heard even usual radio transmissions can be detected by advanced civilization light years away. If there are some in ~100 ly from us, they most likely already know we exist. And this radio bubble we've created is inflating with the speed of light.

Doubtful. The flash would not outshine the sun, so it's got that going against it. They weren't exploded continuously either so only half of the sky would have had a line of sight on them at a given explosion. Then you have to factor in that their instantaneous nature makes it fleetingly unlikely anyone would happen to be pointed their instruments at it at a given time within detection distance from Earth.

Also, our ability to sniff out exo-atmospheres requires months of continuous monitoring and data sorting/analyzing - methods that don't lend themselves particularly well to detection of an atomic weapon explosion. The data sorting is run using algorithms that are configured to look for specific things and requires months of data to be successful. So unless an alien civilization happened to configure their algorithms for bomb sniffing and their detection methods are an order of magnitude more senstive than ours, the odds of detection are very slim. All of these factors are what lead me to be confident in saying 'no' to the question.

The thing is that we only have this planet to investigate as a case study. So if our goal is to not make any assumptions, we have to assume that until proven otherwise, what we know about evolution what we've already learned. And as such this leads to certain conclusions, such as the ones I've made.

I agree that things could be different on other planets, but we have no idea how or in what way. It could be hypothetically possible to set up experiments using fruit flies (or other organisms) to study some of the potential effects you propose. So it would be possible to study, it seems, perhaps.

In the end though, without making any assumptions whatsoever, we have to assume that we better be careful when running into other intelligent life.

Biology and evolution follow the same physics, chemistry and maths everywhere in the universe. From that we can deduce an awful lot of scenarios that have no counterparts on Earth - all we lack is imagination, not really a lack of evidence. (though duh, evidence of life is great for its own sake and is of course informative) We know the rules of the game. We know of one way that game has played out but there is an infinite number of ways it can go down.

Given that the universe is infinite, I'm not confident in many firm predictions about the biological nature of advanced alien life. There's too many unknowns for me to go along with an apex-predator (and Earth predator at that - the very word may be meaningless on a lot of worlds) as the predominant model for their behavior.

Even still, I strongly think caution is warranted.

Red elk makes a valid point (sure, not fallout, but...) The actual x-ray flux and gamma radiation from our thermonuclear (fusion weapons) testing in the 1950s and 60s would be highly identifiable signals to extraterrestrials. Vast amounts of ionizing radiation are given off in a flash, though the actual radiation levels seem to be classified. Consider Castle Bravo or the Tsar Bomba.

In a nuclear war, the duration of the flashes would be mere days - but in a "Cold War" like we had on Earth, there would be a series of flashes over decades - representing a certain technological achievement (sic) level. I would think the flashes would be highly characteristic and revealing. They include a fission bomb precursor,and then the fusion detonation itself (one, TWO!), as well as a distinguishable energy signature.

SETI alone would be singularly unequipped to recognize these detonations.

I said above why I think detonation detection is unlikely but you raised an interesting point. I actually think a nuclear war would be far more detectable an event than a cold war testing scenario.

A war would effectively be one massive explosion as seen from extra-solar distances, far more bright than any single underground or atmospheric test. The brightness of this single even would easily be 1000x-10,000x brighter than any test. Plus, it happens all over the globe which yields at least 2x higher detection ability (because the Earth blocks half the sky [actually a bit more]). While a cold war testing scenario may give you a great many more 'events' (lets say 500 because no civilization would be able to detonate more than that in an atmosphere and survive), they will still be much dimmer and therefore much harder to spot.

So (made up numbers)

1000x brighter times 2x the sky-coverage >>> 500x small explosions

[Plus most aliens would do most if not all testing underground; possibly space but I don't find that particularly likely]

Also - do you not like SETI or something? I get that vibe

 

[red_elk]

Also, our ability to sniff out exo-atmospheres requires months of continuous monitoring and data sorting/analyzing - methods that don't lend themselves particularly well to detection of an atomic weapon explosion. The data sorting is run using algorithms that are configured to look for specific things and requires months of data to be successful. So unless an alien civilization happened to configure their algorithms for bomb sniffing and their detection methods are an order of magnitude more senstive than ours, the odds of detection are very slim. All of these factors are what lead me to be confident in saying 'no' to the question.

I understand that our current technology level makes such detection nearly impossible for us. But if we assume aliens exist, it doesn't feel so unlikely that they may have far more advanced detection methods and that they also have some kind of SETI program looking specifically for civilizations advanced enough to invent termonuclear weapons.

In order to destroy them, before they invented FTL travel and warp weapons

 

[hobbsyoyo]

That's only one of the specific problems in the chain of things that have to go exactly right for an alien civilization to even be able to detect our bomb detonations. We can quibble about the individual probabilities until the cows come home without meaningfully changing the final overall statistics.


-Having said that -

Drake was a very smart man and he made his own chain of probabilities that Glassfan and others have poked many holes in. I could be dead wrong on just about all of my assumptions here that aren't based on physics and geometry and I don't presume to know better than experts.

 

[warpus]

Biology and evolution follow the same physics, chemistry and maths everywhere in the universe. From that we can deduce an awful lot of scenarios that have no counterparts on Earth - all we lack is imagination, not really a lack of evidence. (though duh, evidence of life is great for its own sake and is of course informative) We know the rules of the game. We know of one way that game has played out but there is an infinite number of ways it can go down.

Given that the universe is infinite, I'm not confident in many firm predictions about the biological nature of advanced alien life. There's too many unknowns for me to go along with an apex-predator (and Earth predator at that - the very word may be meaningless on a lot of worlds) as the predominant model for their behavior.

In the end though, out of all the data we have, the only conclusions we can draw is that evolution produces species at the top of the food chain that are predators. This doesn't always happen, again according to the only data we have, but it seems to be a very common occurrence.

I agree that on another planet evolution could have lead to something completely different, but we don't have access to data that shows us such a thing, so the only reasonable thing to do is to go with the data we have, for now, and to update our models once we have new data.

I get that our data is wildly incomplete, but it's all we have to go on. So instead of making assumptions that aren't based on factual data, I think we should be careful when coming into contact with intelligent life from other planets.

It seems the prudent course of action, given what we know, and what's at stake, IMO.