New SETI Study: Why We Might Have Been Missing Alien Signals (seti.org) 101
After decades of searching for extraterrestrial intelligence, the nonprofit SETI Foundation has an announcement. "A new study by researchers at the SETI Institute suggests stellar 'space weather' could make radio signals from extraterrestrial intelligence harder to detect."
Stellar activity and plasma turbulence near a transmitting planet can broaden an otherwise ultra-narrow signal, spreading its power across more frequencies and making it more difficult to detect in traditional narrowband searches. For decades, many SETI experiments have focused on identifying spikes in frequency — signals unlikely to be produced by natural astrophysical processes. But the new research highlights an overlooked complication: even if an extraterrestrial transmitter produces a perfectly narrow signal, it may not remain narrow by the time it leaves its home system... "If a signal gets broadened by its own star's environment, it can slip below our detection thresholds, even if it's there, potentially helping explain some of the radio silence we've seen in technosignature searches," said Dr. Vishal Gajjar, Astronomer at the SETI Institute and lead author of the paper.
The researchers created "a practical framework for estimating how much broadening could occur for different types of stars" — and accounting for space weather — by "using radio transmissions from spacecraft in our own solar system, then extrapolated to other stellar environments."
The study's co-author (a SETI Institute research assistant) suggests this coud lead to better-targetted SETI searches. (M-dwarf stars — about 75% of stars in the Milky Way — actually have the highest likelihood that narrowband signals would get broadened before leaving their system...)
The researchers created "a practical framework for estimating how much broadening could occur for different types of stars" — and accounting for space weather — by "using radio transmissions from spacecraft in our own solar system, then extrapolated to other stellar environments."
The study's co-author (a SETI Institute research assistant) suggests this coud lead to better-targetted SETI searches. (M-dwarf stars — about 75% of stars in the Milky Way — actually have the highest likelihood that narrowband signals would get broadened before leaving their system...)
Frequency Spikes? (Score:2)
"_spikes in frequency_ — signals unlikely to be produced by natural astrophysical processes..."
Then how are we able to detect lightning spikes on an extrasolar planet 124 light years from Earth?
https://www.snexplores.org/art... [snexplores.org]
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Nope, it's aliens.
Seriously, that research is ten years old. Have we not looked at this radiation source since ?
Re:Frequency Spikes? (Score:4, Informative)
An average lightning bolt generates 1 megawatt of radio frequency energy. The earth has 40 million lightning bolts a day. This planet has 500 times that many. That is a lot more energy than any radio signal man has ever created. I'd guess more than man has created in 100+ years!
Re:Frequency Spikes? (Score:5, Informative)
You are misinterpreting the words. A frequency spice means a signal, which has a high power in a very narrow range of frequencies. A lightning is a very high power in a short amount of time. Those are two different types of phenomenon.
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If we can detect lightning from a planet 124 light years from Earth, and see no other potential communications from intelligent life, we should probably be looking closer at those lightning signals.
Notsayinitsaliensitsaliens.
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They might just be hiding. There is a good argument to say that we should avoid being detected, because there is no way of knowing what the reaction might be. First thing we know of it might be the planet killing asteroid mysteriously headed our way.
Re: Is there alien intelligence out there? (Score:2)
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The same could be said about atheists.
That is unless anyone has definitive and incontrovertible proof to the contray. I'm sure we'd all appreciate seeing it.
Remember, the lack of proof that something exists is not, in itse
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exactly, so admit that your lack of proof that there isn't more to this than you or we understand
your arrogance is showing, yup you understand everything perfectly
real honesty is admitting we can't know
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that's a lot of empty rack space for one private server
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that's a lot of empty rack space for one private server
Room for expansion, perhaps?
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should have happened already
i bet we're just not ethical enough, there must be a standard
i wouldn't let the evil people who run this planet loose either
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We are alone. This is our private server.
I have sometimes heard new game players say that, then I ask a few questions and it becomes clear that they are on a company server. But the game is so large that they have just not met any other players yet. Can be unfortunate if it is a PVP server... 8-}
Re:Is there alien intelligence out there? (Score:5, Informative)
God created a vast universe He isn't happy with JUST us.
This was Giordano Bruno's (1548-1600) argument, which got him burned on a stake. If Copernicus was right, and Earth revolves around the Sun, then all the other stars are other suns, with other planets revolving around them and other humans on planets. Hence, he said: "Your God is to small for the Universe."
Bruno's Book (Score:3, Interesting)
De Immenso et Innumerabilibus On the Infinite and the Countless By Giordano Bruno Of Nola
is essential reading. It sounds like 1950's sci fi.
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An alternative take: God created humans, immediately realized what headaches they'd keep causing him - and said "you know, the universe definitely doesn't need TWO planets full of these idiotic monkeys...".
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The Milky Way is home to about a billion civilizations more advanced than us. We are late to the party.
Fortunately space is really big, or we would be them.
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Now prove it.
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God created a vast universe He isn't happy with JUST us. That is one argument.
Interestingly, in one of the Gnostic Gospels, Jesus is quoted as saying when he departed that he had to go visit "sheep of other folds, that you know not of".
(paraphrasing from memory)
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If someone built a house for you, it would not guarantee that every room was a place you would want to sleep. Particularly, if the basement has a water leak... 8-)
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It is a mathematical certainty there is life on other planets. If it can happen here, even at a 1 in 1 billion chance....there are, as far as we know, an infinite number of planets, therefore, it'll happen again, elsewhere. Now whether we will recognize or even meet that life, remains unknown.
Yes, but they don't want to spoil the petri dish. (Score:2)
So the FP branch was a dud and this hopefully more relevant branch led nowhere. It's a long branch and I looked at all the visible posts and didn't see anything I'd classify in the big 3 "I"s, though there were a couple of shouldda got Funnies in there.
I'm increasingly convinced there must be some long-lived intelligent entities, but I doubt they are organic. If they were apex predators, then they would have eaten us already, but I do think they are apex entities in the sense of not having any enemies that
Peak Detectability (Score:5, Insightful)
In our experience of a single planet, we can see a greater reason. We have passed the peak of our detectability to outside civilizations. While we still radiate some narrow band signals, there are fewer than there were a few decades ago. The first world countries no longer beam out carrier based television signals. The current methods of TV transmission would be undetectable without prior knowledge of the details of the modulation methods. Our navigation no longer uses the powerful narrow band LORAN, the replacement satellite based systems would also be undetectable. Sure, a hundred-odd years past the invention of radio we still send narrow band AM/FM broadcast radio signals, but will they be there in a hundred years? If this is a typical trajectory for technology, there might only be a couple hundred years, of the 3 billion plus year history of life, when earth would have a detectable radio signature.
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"The first world countries no longer beam out carrier based television signals"
Sorry, what? If you think digital TV signals dont use carriers think again.
"The current methods of TV transmission would be undetectable without prior knowledge of the details of the modulation methods"
BS. Look on a spectrograph and digital signals - even ones with multiple carriers - stand out like the proverbial sore thumb from the background noise. If that wasn't the case the military wouldn't have to use methods like spread s
Re:Peak Detectability (Score:5, Informative)
In ATSC8VSB 0.5% of the power is in the pilot tone, the rest is spread over the entire bandwidth as subcarriers. Analog TV put 70% of the signal into the single frequency of the carrier. Add in doppler shifts from planet rotation and the perspective from space of seeing all stations on all the channels, and you would be left with a sight rise in the background noise, not a detectable signal.
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Subcarriers are still carriers and if the signal was undetectable it would also be undecodable.
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Good lord, do the math already.
If we look at a DTV broadcast (@ 640MHz), and assume a "high gain" receiver (with 60dB antenna gain--a
This is why looking for any signal needs to be constrained to a very narrow bandwidth, i.e. to force the noise in the receiver low enough there's a chance in hell to detect something. At 1 Hz, the noise floor is -174 dBm, about 70dB better, meaning you are only off by 30dB (a factor of 1000), and it's at least conceivable something out there is blasting out a power level in
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Good lord, do the math already.
If we look at a DTV broadcast (@ 640MHz), and assume a "high gain" receiver (with 60dB antenna gain--a
WTF happened to the first paragraph? Ugh. Anyway, assumptions were 640 MHz carrier, 6MHz modulation, 60dB Rx antenna gain (.1 deg beam width). Free space loss is about 288 dB, Noise floor in receiver is about -106 dBm. With a 50kW (77 dBm) transmitter, you're 100dB below the noise floor at 1 light year.
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SETI Is Stoopid (Score:1)
They haven't a clue. They're too stoopid to realize that alien communication technology is undetectable. It uses quantum entanglement and gravitational brainwaves for the bearer channel. It also uses unbreakable alien encryption technology.
Aliens are LTFAO at SETI and their primitive attempts.
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There are no FTL speeds. No exceptions.
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just keep the poor busy with cheap entertainment and use shock and awe to distract and confuse us
People are already being entertained buy the unending revelations from the Epstein files.
And shocked, though not particularly awed.
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What if this latest adventure in Iran is just a smokescreen
Call it by its proper name, Operation Epstein Fury!
Re:SETI Is Stoopid (Score:4, Informative)
Other similar stars were here in this galaxy for 8 billion years before the Sun even formed - twice as long as then to now. Inception of life as we know it on Earth was effectively instant upon planet formation, which was contemporaneous with solar ignition.
Waste of time (Score:2)
Weak signals over a long distance. You may as well try to listen to people whispering in China from the US.
(Why would a civilization dedicate a large amount of resources, say 1,000+ nuclear power plants, to send a very narrow signal into the void hoping for a billion+ to one chance of hitting our little planet at a time we are listing - Not before the Romans or after we're cooked. Engineers start with: how can I send the message with as little cost (materials, power, etc) as possible? If they over enginee
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They might do it for other reasons, however. Say to communicate with a generation ship en-route to a distant star. But it *does* make it a lot more unlikely.
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Maybe they're looking for the heat signature of crypto mining.
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Why would a civilization dedicate a large amount of resources, say 1,000+ nuclear power plants, to send a very narrow signal into the void hoping for a billion+ to one chance of hitting our little planet at a time we are listing,
The assumption of SETI is not that alien civilizations are doing that necessarily on purpose to contact us. The assumption is that signals are sent out on purpose or inadvertently as the humans send out signals all the time through entertainment and communication broadcasts.
Required signal strength ? (Score:5, Interesting)
I'd be interested to see some analysis of how strong of a signal an alien civilization would need to be transmitting for us to have any chance of detecting it with our networks of radio telescopes.
Sure we can hear Voyager's weak signal, which is impressive, but in the galactic scale of things it is right beside us, only just having left our solar system.
Any potential aliens are much, much further away ... On a scale where our sun is a grain of sand, the closest star is another grain of sand 600 miles away, with radio signal strength weakening according to an inverse square law.
Of course it's almost certain that the closest alien civilization (assuming one exists) capable of radio transmission isn't so conveniently close by, and if it was on the other side of our galaxy (100,000 light years away, not just 4), then what sort of transmitter power would they need to be using? The inverse square law is brutal.
What if the nearest civilization if not even in our own galaxy?
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I don't think we have any reason to suppose that we're the only technological civilization within 300 light years. OTOH, within 4 light year the odds are quite good that there aren't any.
That said, I wouldn't want to guess how far it is to the closest other technological civilization...not without a better estimate of the lifetime of such civilizations. (My guess is that they're typically pretty short, but that it's possible to build enduring ones...but that this requires moving parts of the civilization
Re:Required signal strength ? (Score:5, Informative)
I expect that life itself is not rare - that the universe is teaming with life, but maybe only at simple prokaryotic cell type of level. The emergence of "life" (self encoding self-replicators) from non-life seems somewhat inevitable when a few conditions are in place.
The case for advanced civilizations being rare is from looking at the earth (a sample of one, but still ...). Earth is almost as old as the universe. Simple life here arose almost immediately about 4B years ago, but it took another 2B years for eukaryotic cells to emerge, the Cambiran Explosion of diversity of life only happened 500M years ago, humans only emerged a few million years ago, and our ability to transmit radio signals happened yesterday.
Earth seems like a goldilocks planet, so why to expect a much different timeline on other planets? Some of these transitions such as from simple replicator cells to eukaryotic ones with the complexity necessary for multi-cellular life are apparently far from a slam-dunk (having taken 2B years to happen here, and by all estimates only ever having happened once). If life here on earth, almost as old as the universe itself, only became capable of transmitting a radio signal 100 years ago, then why to expect that life on other planets is so much further than ahead of us? Maybe there is another radio-transmitting civilization on the other side of our galaxy, but if they only just started transmitting 100 years ago, then the radio signals are still in transit and will take another 100,000 years to reach us ... assuming they were transmitting at whatever absurd power levels would be necessary for us to be able to detect it.
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Almost as old as the universe? 4.5 Billion versus 13.8 Billion. Am I missing something here?
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No :) I was thinking of Milky Way age.
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Thanks, I'll look it up. Didn't realize the milky way was so young, relatively.
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No - the opposite, it's the Milky Way (not the earth) that is almost as old as the universe.
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I don't think the eukaryotic cell was that difficult a transition. Consider mixotricha paradoxa, which is, essentially, the reinvention of the eukaryotic cell at a higher level. That only one germline of "eukaryitic-like" cells survived to the present isn't really a very good argument that in the deep past there weren't several. Most gene-lines eventually go extinct.
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OK, so possibly complex cells evolved more than once, but apparently still a rare enough event (and/or one dependent on a lot of other things happening first) that it took a long time (2B years) to happen. If eukaryotic cells, and multicellular life, had appeared sooner it might suggest some inevitability to this progression, but it seems that at least one reading of the slow emergence is that this was a very low-probability event.
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Earth is not remotely as old as the Universe.
Age of the universe is about 13.8 Billion years - https://en.wikipedia.org/wiki/... [wikipedia.org]
The age of the Sun is only about 4.6 billion years - https://en.wikipedia.org/wiki/... [wikipedia.org]
Earth in turn is slightly younger than the Sun, at about 4.54 billion years - https://en.wikipedia.org/wiki/... [wikipedia.org]
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Voyager has a tiny radio transmitter that's much weaker because of a limited power budget. The earth itself has much more powerful transmitters that would be far easier to receive. Radio stations are transmitting at multiple kilowatts to reach a city, but it's several orders of magnitude greater than what Voyager could transmit.
The other problem is as we moved from analog to digital transmissions, our radio emissions moved from artificial "not natural signals" to more noise-like. Indeed, many modulation tec
Communications (Score:4, Funny)
Just tattoo the insides of rednecks' assholes, who usually get abducted, with messages for the aliens.
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Pretty good joke, but the topic deserved more. I saw a couple of almost-funny candidates, but never have a mod point to bestow, so...
That's wishful thinking (Score:4, Insightful)
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Well, you gotta at least try...
Maybe SETI should rethink their whole approach? (Score:5, Insightful)
If all you have is a 1950ies radio antenna, what would you make of today's mobile phone signals? Would you recognize them as being artificial?
Already in the 1960ies, Polish SF author Stanislaw Lem in his essay "Summa technologiae" doubted the idea of "techno signatures" in radio signals. His argument? With better technology, we are better able to use the bandwidth of our signals, and with better usage of the bandwidth, the required signal-to-noise ratio gets lower, and the signal looks more and more like white noise to someone not knowing the technology. Additional, the power requirements to transmit a signal gets lower and lower too, and much less signal is wasted into space. The time frame in which electromagnetic waves from artificial sources look noticeably different from natural radiation is very short, it was less than 100 years for the human civilization.
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If all you have is a 1950ies radio antenna, what would you make of today's mobile phone signals? Would you recognize them as being artificial?
Absolutely. I think you are misunderstanding the difference between being able to interpret content of signals with being able to tell if a signal is artificial or naturally occurring. As humans have been listening to the Universe for decades now, there is a huge catalog of naturally occurring signals.
Yeah, not necessary (Score:2)
We don't even have the ability to detect our civilization from the distances involved.
Dang it, Querellionix hang up the phone (Score:2)
your dad was trying to use the intergalactic modem to contact Earth. I swear, you kids. . .
maybe... (Score:2)
the aliens have become very good at hiding their existence from self-immolating viruses.
No one is signalling... (Score:2)
It is very unlikely that we will pick up a signal sent our way.
1. The other civilization would have to deliberately send a strong, narrow signal to our star. Why would they do that? See comment below about detectability: maybe they actually would, if they could detect us, but they cannot.
2. e would have to be looking at the exact moment that they send the signal. Consider the time periods involved: our planet has existed for billions of years, and only for about 1/10000000 of that time have we had the cap
Arrogance (Score:3)
Because it is our arrogance to think that signals must exist in the electromagnetic realm. We DO NOT know the ins and outs of the universe. Physics is NOT how things work. It's what we show and demonstrate and wrap math around. We've had, what a couple hundred years in using radio signals to communicate. The trilobites had MILLIONS of years to work on their understanding of the universe, and thinking that we would be able to find a millennia of EM usage historical representation of trilobite technology is just goofy. Science is WHAT WE CAN SAY about how the universe works, proven through decades of other scientists trying to break any theory. There is no reason to think that we will not scrap EM in a few millennia and look back at how innocent and quaint we were to think that EM runs the universe. All that the scientists are presenting their data. It's the ignorant "reporters" who put all these grand theories around it. Good data. Keep looking. That's what science does. Pretty boring huh?
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If you have discovered something that replaces EM radiation, please let us all know when you have collected your Nobel prize for physics, having successfully re-written the majority of it.
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Because it is our arrogance to think that signals must exist in the electromagnetic realm.
As opposed to what? EM is the science we know. I do not know of human ability to detect other realms. For example subspace communication is an FTL system that exists in Star Trek and other franchises. It is theoretical at best.
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As opposed to what? EM is the science we know. I do not know of human ability to detect other realms. For example subspace communication is an FTL system that exists in Star Trek and other franchises. It is theoretical at best.
Anything that is outside your house is theoretical. Until you go there, then it gets real. Also, humans don't know everything... 8-}
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Anything that is outside your house is theoretical. Until you go there, then it gets real. Also, humans don't know everything... 8-}
No it is not. The world exists. The problem with the assertion is scientists use the EM spectrum because we know it exists; they cannot use something they do not know exists. How do you use something that you don't know exists? That's saying I should teleport to my next vacation instead of driving or flying because I don't know every form of travel.
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Because it is our arrogance to think that signals must exist in the electromagnetic realm.
As opposed to what? EM is the science we know. I do not know of human ability to detect other realms....
Communication by neutrinos, perhaps?
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Communication by neutrinos, perhaps?
Neutrinos are not from other realms; neutrinos are not FTL. We can detect neutrinos; the problem with using neutrinos is that they exist everywhere especially since the Earth is 8 light minutes from a major source of neutrinos. That is like trying to talk to someone during a concert when both of you are right next to a loud speaker.
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No, it doesn't. Like much of QM, it doesn't seem subject to common sense assessment. The interaction is instantaneous, but it can't be used to communicate.
The universe doesn't allow FTL.
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hohum (Score:2)
Give it up, already.
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I have a different explanation (Score:2)
Who really thinks (Score:2)
Can you see a Alien civilization using radios "10-4 good buddy, we just passed Uranus headed for Earth. Going to pick up a load of Humans for scientific study."
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Who really thinks advanced civilizations and communicating via radio signals? If they are far more advanced than us they would be using some other kind of communication that radios. Please....
1) The assumption is the civilizations might be communicating by radio. But they are also likely to be leaking radio signals which are not natural or artificial. For example, humans have been leaking radio signals through space as it was how radio/TV broadcasts work. 2) Due to long distances and doppler shift, the other assumption is that the signal is radio when sent out but is radio by the time we receive it.
Can you see a Alien civilization using radios "10-4 good buddy, we just passed Uranus headed for Earth. Going to pick up a load of Humans for scientific study."
And what medium that humans monitor? The EM spectrum is all we know. Other communication forms lik
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Being warp capable seems indeed a good threshold.