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I haven't seen any anti-METI argument which counters this: "Humans, Vakoch said, have been using radar, which can purportedly be detected 70 light-years away,

I haven't seen any anti-METI argument which counters this: "Humans, Vakoch said, have been using radar, which can purportedly be detected 70 light-years away, since World War II. Television and radio signals would long ago have signaled our presence to malevolent space ruffians, he said."

deleted 8y ago
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blueadept111 8y ago
Counter argument: So if we've been using radar since WWII, and radar has been capable of signalling our presence to alien civilizations, then we don't need METI. Alternatively, if METI is proposing a signal that can reach alien civilizations in a way that TV and radio signals cannot, then the original objections to METI still stand, and the TV/radio signal argument is a red herring. But really, it's just common sense. Everything we know about the universe tells us that complex organisms exist at the expense of simpler organisms. As a nascent space-faring civilization, we are the minnows in the ocean, and signalling our presence to the bigger fish is the kind of mistake that a minnow only makes once. What exactly is the perceived positive outcome of making contact with a more advanced civilization?
- svachalek 8y ago
  This, exactly. What METI is proposing, as I understand, is a stronger, more unmistakable signal of intelligence which carries higher risks. Also, this is 70 years of noise, a blip on the galactic timescale, getting weaker the farther it goes. We can't stop what's gone out already but that doesn't make us obligated to keep advertising our presence forever.
- SOMA_BOFH 8y ago
  Is there a proposal from METI more capable of reaching out than this 32MW transmitter with a 1.4° beamwidth which has been operating continuously for decades? https://en.wikipedia.org/wiki/Eglin_AFB_Site_C-6#How_the_radar_works https://en.wikipedia.org/wiki/Eglin_AFB_Site_C-6#How_the_rad...
headcanon 8y ago
A counter to that might be that these signals aren't strong enough to accurately detect our exact location at interstellar distances. Parallax is hard at those distances - if we were to get a signal from a point in the sky, whats to say its coming from one star, or another one "behind" it? Not possible to determine from the signal strength alone, since you don't know the signal's original strength. In Carl Sagan's Contact, we were only able to determine the signal came from the star Vega because it was the only star that would have been at the right distance to receive our earliest radio signal and transmit it back to us - also Vega is relatively close by compared to other stars, close enough that our parallax created by our orbit around Sol was sufficient to get a read on signal source. A deliberate attempt at active signaling would remove all doubt for an extrasolar observer. Liu Cixin's The Dark Forest explores this scenario in depth. I would explain more but don't want to reveal some important spoilers.
- jandrese 8y ago
  It might be hard for us to figure out where the signal is coming from, but an alien race that is capable of traveling between star systems shouldn't have any problem figuring it out. Frankly if such an alien race exists they already know there is life on Earth just from the changes in chemical composition of our atmosphere. They can even figure out when we discovered agriculture. In a few decades they will even know that we discovered radio communication.
CharlesColeman 8y ago
> I haven't seen any anti-METI argument which counters this: > "Humans, Vakoch said, have been using radar, which can purportedly be detected 70 light-years away, since World War II. Television and radio signals would long ago have signaled our presence to malevolent space ruffians, he said." I think the key word there is "purportedly." Has anyone done an analysis about what kind of equipment would be required to detect those old signals at 70 light years? Has there been any analysis of how for out they could propagate until they were totally overwhelmed by noise? Personally, I'm skeptical that those signals were transmitted powerfully enough or focused narrowly enough to likely be detected. This article (https://www.nature.com/articles/461316a https://www.nature.com/articles/461316a) makes it sound that way: > Indeed, SETI is marked by a hope, bordering on faith, that not only are there civilizations broadcasting out there, but that they are somehow intent on beaming their signals at Earth. An alien SETI project relying on a similar faith in Earth would be sorely disappointed. It's true that a random mix of radar and television signals has been expanding outwards from Earth at the speed of light for the past 70 years. But there have been only a few short-lived attempts to target radio messages at other stars — with each attempt arousing concerns over alien reprisals.
jerf 8y ago
The atmosphere point is even more compelling. Earth has been broadcasting with quite non-trivial power "I HAVE LIFE" for about two and a half billion years. Most of the "hostile alien" hypothesis work out to the hostile aliens needing to exterminate all life, not just life that already seems to be intelligent, because you don't know how fast something might become intelligent when you're not looking, so if Earth was going to be wiped out, it should have been a very, very long time ago. https://en.wikipedia.org/wiki/Great_Oxygenation_Event https://en.wikipedia.org/wiki/Great_Oxygenation_Event (Since someone will probably bring it up, no, I do not believe extinction events are aliens trying to wipe out life, on the grounds that if intelligent, hostile aliens intended to wipe out life on Earth, I'd expect them to succeed, and not merely inconvenience life briefly, but actually totally and permanently sterilize Earth. Any culture that can fling either mass or energy at early Earth in any reasonable period of time is already very near the necessary energies to do that. Across billions of years I'd expect someone to have managed.) Another reason why I tend towards the "yeah, we are non-trivially alone" myself. Maybe the entire universe isn't empty, but I don't think there's any reason to believe there's anything nearby.
- pmoriarty 8y ago
  "The atmosphere point is even more compelling. Earth has been broadcasting with quite non-trivial power "I HAVE LIFE" for about two and a half billion years. Most of the "hostile alien" hypothesis work out to the hostile aliens needing to exterminate all life, not just life that already seems to be intelligent, because you don't know how fast something might become intelligent when you're not looking, so if Earth was going to be wiped out, it should have been a very, very long time ago." Even if they're out to destroy all life, they might prioritize killing intelligent life first, as it could be a threat (or for some other reason).
  - jerf 8y ago
    Obviously known-intelligent life would be a priority, but if they can't get around to the lower priority stuff in 2.5 billion years, well, why should we take the Dark Forest argument any more seriously than any of the other civilizations we've cruised by in the past 2.5 billion years? The amount of energy available to even a single solar system, let alone all the advanced galactic civilizations that are supposed to be out there, dwarfs what it would take to sterilize Earth. And don't think I'm underestimating that quantity; it's larger than any impact real Earth ever sustained, and it has sustained some doozies. But what's in even a small star, even in a small star's yearly output, is orders of magnitude larger. And this is with the relatively expensive brute force method too; if you're willing to roll the dice on the target not having intelligent life a few steps above where we are now, you could probably put together a gray-goo-esque replicator that would conclusively eliminate any civilizational threat from a given planet permanently, for the cost of delivering a few kilograms of payload to the target system, which is presumably trivial for our advanced civilizations. As I said, I'm still pretty much on the "yeah, we're probably effectively alone" side, because when you really treat the "the universe is full of advanced intelligent life" idea seriously, you just don't get what we see in our sky. Not least of which is the wide variety of ways in which we simply shouldn't exist, because our ecosystem should have been wiped out one way or another, be it by raw destruction, or simply interaction with some other much more advanced ecosystem that simply steamrolled Earth's primitive life the same way we steamroll an ant hill, a billion years ago. Just about the only way to save the hypothesis is that we are the "Progenitors" and the universe is full of intelligent life if you look at a random place and time, it's just that the "full of intelligent life" hasn't happened yet. If the universe as a whole is full of intelligent life, there still has to be a first set of civilizations, and while every individual in those civilizations may rationally say "the odds of me being here when the universe is empty are as good as zero", there still have to be some "lottery winners".
arkades 8y ago
At best, that says “any badness within 70 LY has already been tipped off.” The METI guys are working on more powerful emitters specifically so as to send additional data that will be coherent over larger distances.
maze-le 8y ago
Here is one: Absent any form of antenna technology we don't know about, all of these signals are going to be extremely dispersed and very near to the rate of noise, for any receiver that is even moderately far away. It is still possible to detect these signals, but only you know exactly what you are looking for. Not only the direction and frequency of the signal are needed to know, also amplitude, polarization and any form of modulation pattern. Otherwise, the signal might just be interpreted as noise. Also 70 ly are "not even beyond our backyard" so to speak. 70 ly is such a small distance, compared to other possible distances in our galaxy. It is a far too small patch to be taken as a basis and extrapolate to the rest of the 27000 ly of galaxy ahead of the signal. Maybe the space ruffians are 80 ly away from us, or 800...
dfilppi 8y ago
Really? How many habitable exoplanets are within 70 light years, and what are the odds of life (let alone super-advanced space pirates) existing on them? Also a little known fact: only energy travels at light speed. So even in the worst case scenario, they won't be here for a few hundred years.

deleted 8y ago

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blueadept111 8y ago

Counter argument: So if we've been using radar since WWII, and radar has been capable of signalling our presence to alien civilizations, then we don't need METI. Alternatively, if METI is proposing a signal that can reach alien civilizations in a way that TV and radio signals cannot, then the original objections to METI still stand, and the TV/radio signal argument is a red herring. But really, it's just common sense. Everything we know about the universe tells us that complex organisms exist at the expense of simpler organisms. As a nascent space-faring civilization, we are the minnows in the ocean, and signalling our presence to the bigger fish is the kind of mistake that a minnow only makes once. What exactly is the perceived positive outcome of making contact with a more advanced civilization?

svachalek 8y ago
This, exactly. What METI is proposing, as I understand, is a stronger, more unmistakable signal of intelligence which carries higher risks. Also, this is 70 years of noise, a blip on the galactic timescale, getting weaker the farther it goes. We can't stop what's gone out already but that doesn't make us obligated to keep advertising our presence forever.
SOMA_BOFH 8y ago
Is there a proposal from METI more capable of reaching out than this 32MW transmitter with a 1.4° beamwidth which has been operating continuously for decades? https://en.wikipedia.org/wiki/Eglin_AFB_Site_C-6#How_the_radar_works https://en.wikipedia.org/wiki/Eglin_AFB_Site_C-6#How_the_rad...

headcanon 8y ago

A counter to that might be that these signals aren't strong enough to accurately detect our exact location at interstellar distances. Parallax is hard at those distances - if we were to get a signal from a point in the sky, whats to say its coming from one star, or another one "behind" it? Not possible to determine from the signal strength alone, since you don't know the signal's original strength. In Carl Sagan's Contact, we were only able to determine the signal came from the star Vega because it was the only star that would have been at the right distance to receive our earliest radio signal and transmit it back to us - also Vega is relatively close by compared to other stars, close enough that our parallax created by our orbit around Sol was sufficient to get a read on signal source. A deliberate attempt at active signaling would remove all doubt for an extrasolar observer. Liu Cixin's The Dark Forest explores this scenario in depth. I would explain more but don't want to reveal some important spoilers.

jandrese 8y ago
It might be hard for us to figure out where the signal is coming from, but an alien race that is capable of traveling between star systems shouldn't have any problem figuring it out. Frankly if such an alien race exists they already know there is life on Earth just from the changes in chemical composition of our atmosphere. They can even figure out when we discovered agriculture. In a few decades they will even know that we discovered radio communication.

CharlesColeman 8y ago

> I haven't seen any anti-METI argument which counters this: > "Humans, Vakoch said, have been using radar, which can purportedly be detected 70 light-years away, since World War II. Television and radio signals would long ago have signaled our presence to malevolent space ruffians, he said." I think the key word there is "purportedly." Has anyone done an analysis about what kind of equipment would be required to detect those old signals at 70 light years? Has there been any analysis of how for out they could propagate until they were totally overwhelmed by noise? Personally, I'm skeptical that those signals were transmitted powerfully enough or focused narrowly enough to likely be detected. This article (https://www.nature.com/articles/461316a https://www.nature.com/articles/461316a) makes it sound that way: > Indeed, SETI is marked by a hope, bordering on faith, that not only are there civilizations broadcasting out there, but that they are somehow intent on beaming their signals at Earth. An alien SETI project relying on a similar faith in Earth would be sorely disappointed. It's true that a random mix of radar and television signals has been expanding outwards from Earth at the speed of light for the past 70 years. But there have been only a few short-lived attempts to target radio messages at other stars — with each attempt arousing concerns over alien reprisals.

jerf 8y ago

The atmosphere point is even more compelling. Earth has been broadcasting with quite non-trivial power "I HAVE LIFE" for about two and a half billion years. Most of the "hostile alien" hypothesis work out to the hostile aliens needing to exterminate all life, not just life that already seems to be intelligent, because you don't know how fast something might become intelligent when you're not looking, so if Earth was going to be wiped out, it should have been a very, very long time ago. https://en.wikipedia.org/wiki/Great_Oxygenation_Event https://en.wikipedia.org/wiki/Great_Oxygenation_Event (Since someone will probably bring it up, no, I do not believe extinction events are aliens trying to wipe out life, on the grounds that if intelligent, hostile aliens intended to wipe out life on Earth, I'd expect them to succeed, and not merely inconvenience life briefly, but actually totally and permanently sterilize Earth. Any culture that can fling either mass or energy at early Earth in any reasonable period of time is already very near the necessary energies to do that. Across billions of years I'd expect someone to have managed.) Another reason why I tend towards the "yeah, we are non-trivially alone" myself. Maybe the entire universe isn't empty, but I don't think there's any reason to believe there's anything nearby.

pmoriarty 8y ago
"The atmosphere point is even more compelling. Earth has been broadcasting with quite non-trivial power "I HAVE LIFE" for about two and a half billion years. Most of the "hostile alien" hypothesis work out to the hostile aliens needing to exterminate all life, not just life that already seems to be intelligent, because you don't know how fast something might become intelligent when you're not looking, so if Earth was going to be wiped out, it should have been a very, very long time ago." Even if they're out to destroy all life, they might prioritize killing intelligent life first, as it could be a threat (or for some other reason).
- jerf 8y ago
  Obviously known-intelligent life would be a priority, but if they can't get around to the lower priority stuff in 2.5 billion years, well, why should we take the Dark Forest argument any more seriously than any of the other civilizations we've cruised by in the past 2.5 billion years? The amount of energy available to even a single solar system, let alone all the advanced galactic civilizations that are supposed to be out there, dwarfs what it would take to sterilize Earth. And don't think I'm underestimating that quantity; it's larger than any impact real Earth ever sustained, and it has sustained some doozies. But what's in even a small star, even in a small star's yearly output, is orders of magnitude larger. And this is with the relatively expensive brute force method too; if you're willing to roll the dice on the target not having intelligent life a few steps above where we are now, you could probably put together a gray-goo-esque replicator that would conclusively eliminate any civilizational threat from a given planet permanently, for the cost of delivering a few kilograms of payload to the target system, which is presumably trivial for our advanced civilizations. As I said, I'm still pretty much on the "yeah, we're probably effectively alone" side, because when you really treat the "the universe is full of advanced intelligent life" idea seriously, you just don't get what we see in our sky. Not least of which is the wide variety of ways in which we simply shouldn't exist, because our ecosystem should have been wiped out one way or another, be it by raw destruction, or simply interaction with some other much more advanced ecosystem that simply steamrolled Earth's primitive life the same way we steamroll an ant hill, a billion years ago. Just about the only way to save the hypothesis is that we are the "Progenitors" and the universe is full of intelligent life if you look at a random place and time, it's just that the "full of intelligent life" hasn't happened yet. If the universe as a whole is full of intelligent life, there still has to be a first set of civilizations, and while every individual in those civilizations may rationally say "the odds of me being here when the universe is empty are as good as zero", there still have to be some "lottery winners".

arkades 8y ago

At best, that says “any badness within 70 LY has already been tipped off.” The METI guys are working on more powerful emitters specifically so as to send additional data that will be coherent over larger distances.

maze-le 8y ago

Here is one: Absent any form of antenna technology we don't know about, all of these signals are going to be extremely dispersed and very near to the rate of noise, for any receiver that is even moderately far away. It is still possible to detect these signals, but only you know exactly what you are looking for. Not only the direction and frequency of the signal are needed to know, also amplitude, polarization and any form of modulation pattern. Otherwise, the signal might just be interpreted as noise. Also 70 ly are "not even beyond our backyard" so to speak. 70 ly is such a small distance, compared to other possible distances in our galaxy. It is a far too small patch to be taken as a basis and extrapolate to the rest of the 27000 ly of galaxy ahead of the signal. Maybe the space ruffians are 80 ly away from us, or 800...

dfilppi 8y ago

Really? How many habitable exoplanets are within 70 light years, and what are the odds of life (let alone super-advanced space pirates) existing on them? Also a little known fact: only energy travels at light speed. So even in the worst case scenario, they won't be here for a few hundred years.