SETI detects possible signal at 11 GHz frequency from sun-like star

SETI detects possible signal at 11 GHz frequency from sun-like star
The RATAN-600 radio telescope. Credit: nat-geo.ru

A star system 94 light years away is in the spotlight as a possible candidate for intelligent inhabitants, thanks to the discovery of a radio signal by a group of Russian astronomers.

HD 164595, a solar system a few billion years older than the Sun but centered on a star of comparable size and brightness, is the purported source of a signal found with the RATAN-600 radio telescope in Zelenchukskaya, at the northern foot of the Caucasus Mountains. This system is known to have one planet, a Neptune-sized world in such a very tight orbit, making it unattractive for life. However, there could be other planets in this system that are still undiscovered.

The signal seems to have been discussed in a presentation given by several Russian astronomers as well as Italian researcher, Claudio Maccone, the chair of the International Academy of Astronautics Permanent SETI Committee. Maccone has recently sent an email to SETI scientists in which he describes this presentation, including the signal ascribed to star system HD 164595.

Could it be a transmission from a technically proficient society? At this point, we can only consider what is known so far. This is a technical story, of course.

First, is the detected signal really coming from the direction of HD 164595? The RATAN-600 is of an unusual design (a ring on the ground of diameter 577 meters), and has an unusual "beam shape" (the patch of sky to which it is sensitive). At the wavelength of the reported signal, 2.7 cm – which is equivalent to a frequency of 11 GHz – the beam is about 20 arcsec by 2 arcmin. In other words, it's a patch that's highly elongated in the north-south direction.

The patch from which the signal seems to be coming agrees in the east-west direction (the narrow part of the beam) with HD 165695's sky coordinates, so that's the basis of the assumption by the discoverers that this is likely to be coming from that star system. But of course, that's not necessarily the case.

Second is the question of the characteristics of the signal itself. The observations were made with a receiver having a bandwidth of 1 GHz. That's a billion times wider than the bandwidths traditionally used for SETI, and is 200 times wider than a television signal. The strength of the signal was 0.75 Janskys, or in common parlance, "weak." But was it weak only because of the distance of HD 164595? Perhaps it was weak because of "dilution" of the signal by the very wide bandwidth of the Russian receiver? Just as a pot pie, incorporating lots of ingredients, can make guessing the individual foodstuffs more difficult, a wide-bandwidth receiver can dilute the strength of relatively strong narrow-band signals.

Now note that we can work backwards from the strength of the received signal to calculate how powerful an alien transmitter anywhere near HD 164595 would have to be. There are two interesting cases:

(1) They decide to broadcast in all directions. Then the required power is 1020 watts, or 100 billion billion watts. That's hundreds of times more energy than all the sunlight falling on Earth, and would obviously require power sources far beyond any we have.

(2) They aim their transmission at us. This will reduce the power requirement, but even if they are using an antenna the size of the 1000-foot Arecibo instrument, they would still need to wield more than a trillion watts, which is comparable to the total energy consumption of all humankind.

Both scenarios require an effort far, far beyond what we ourselves could do, and it's hard to understand why anyone would want to target our solar system with a strong signal. This star system is so far away they won't have yet picked up any TV or radar that would tell them that we're here.

Enter the Allen Telescope Array

The chance that this is truly a signal from extraterrestrials is not terribly promising, and the discoverers themselves apparently doubt that they've found ET. Nonetheless, one should check out all reasonable possibilities, given the importance of the subject.

Consequently, the Allen Telescope Array (ATA) was swung in the direction of HD 164595 beginning on the evening of August 28. According to our scientists Jon Richards and Gerry Harp, it has so far not found any signal anywhere in the very large patch of sky covered by the ATA.

However, we have not yet covered the full range of frequencies in which the signal could be located, if it's of far narrower bandwidth than the Russian 1 GHz receiver. We intend to completely cover this big swath of the radio dial in the next day or two. A detection, of course, would immediately spur the SETI and radio astronomy communities to do more follow-up observations.

We will continue to monitor this with the array.

One particularly noteworthy thing about this discovery is the fact that the signal was apparently observed in May, 2015 (it seems that this was the only time in 39 tries that they saw this signal). The discoverers didn't alert the SETI community to this find until now, which is not as expected. According to both practice and protocol, if a signal seems to be of deliberate and extraterrestrial origin, one of the first things to do is to get others to attempt confirming observations. That was not done in this case.

So what's the bottom line? Could it be another society sending a signal our way? Of course, that's possible. However, there are many other plausible explanations for this claimed transmission – including terrestrial interference. Without a confirmation of this signal, we can only say that it's "interesting."


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'Strong signal' stirs interest in hunt for alien life

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Aug 30, 2016
This system is known to have one planet, a Neptune-sized world in such a very tight orbit, making it unattractive for life.

One that we know of. It's not like we can detect all planets in a solar system with certainty and then say "that's it" (not even our own).

and it's hard to understand why anyone would want to target our solar system with a strong signal.

Moreover: If they were to target us with such a signal - why would they stop?

According to both practice and protocol, if a signal seems to be of deliberate and extraterrestrial origin

Werl...if you're working for one of those nations with spy satellites in orbit you probably want to go check with your government first. Would be downright embarassing if you just broadcast the position of one of those dark sattelites to the world in your press release about aliens, wouldn't it?

Aug 30, 2016
How about the apparent fact the signal doesn't have any complexity for: 1. transmitting a message; or 2. distinguishing itself from natural sources? So we receive a non-repeating 11 GHz wideband tone for couple seconds, but someone wanting to communicate with us should have known that could be interpreted as a natural phenomenon. As I recall, in the book/movie Contact the aliens used prime numbers. A society advanced enough to build such a powerful transmitter seeking a response would try to distinguish their signal from natural sources, if not send an actual message, so that isn't it. On the other hand, maybe our receipt of the signals was unintentional, which raises a host of other possibilities. But even then, it is awfully powerful for such a simplistic signal, which doesn't make a lot of sense. Most likely, it is a man-made or natural phenomenon, but we should keep an eye on that star, in any case.

Aug 30, 2016
I think the 'power requirements' are overblown just in order to 'poo-poo' the signal. WE got it. WE have been sending signals out into space in all directions all over the EM spectrum that we can reach for over 150 or more years, and maybe civilizations before us now gone have done the same. We have satellites, Voyagers one and two have less than the output of a common wimpy digital cellfone and they are now all the way out of our Sol solar system and WE RECEIVE THEM JUST FINE! Energy field vectors can be played with all anyone wants to play with the numbers.
However, if we play devil's advocate and agree with the so called power requirements, then no wonder we have not 'heard' from anyone' cuz' NOBODY HAS A TRANSMITTER THAT CAN REACH HERE' with ordinary radial spherical output sending equipment of power available to us. Perhaps SETI should consider going to space to put up a much larger antenna array. Perfect justification is IN this article.

Aug 30, 2016
This title is misleading. It was a Russian team that observed the signal; we're still waiting for SETI to corroborate.

Aug 30, 2016
Maybe someone fell on that planet and is sending an SOS. Being an alien, it doesn't know Morse code so it does what it can, namely it whistles on some random frequency that only military satellites use.

Aug 30, 2016
Voyagers one and two have less than the output of a common wimpy digital cellfone and they are now all the way out of our Sol solar system and WE RECEIVE THEM JUST FINE!


Just barely. The data rate is a handful of bits per second and dropping as the integration time necessary to make out the signal from the background noise grows longer with distance. You forget that the signal drops at the square of distance, and the voyagers are mere light-hours away.

The signal at 100 light years away would be 6 billion times weaker. To recieve one byte of information from a Voyager-powered transmitter, the bit-rate would have to be slowed down so much that you'd have to listen to the same spot of sky for 170 years.

Aug 30, 2016
Will we ever really know a signal from an alien world? In the past century, we have advanced from spark-gap transmitters to analog signaling such as AM or FM radio and television, to sophisticated digital communications, which have been optimized practically to the Shannon bound. Modern communication signals look like noise. Some, like ATSC, have periodic content in them, but others, like satellite broadcasts are pure noiselike signals. Modern communication systems are designed with a link budget (signal power) to match the channel -- if you were communicating to a satellite in geosynchronous orbit, your power would match that link with enought to overcome most rain fades. Without knowledge about the symbols, modulation, coding principles, or understanding of its purpose, deciphering an extraterrestrial signal must be a puzzle of unimiaginable complexity. A modern communication signal would be jibberish to the brightest minds 50 years ago if it could have been even observed.

Aug 30, 2016
knutonp: I agree with your rough analysis (in addition to the signal/noise power arguments), but would add that no one is ever likely to just 'eavesdrop' on another system's communication. If we ever do detect interstellar communication, it would almost certainly have to be of the intentional kind that we've tried to send in the past. So, yes I would imagine we *could* know a signal from an alien world... just one they want us to see explicitly, rather than by chance.

Aug 30, 2016

and it's hard to understand why anyone would want to target our solar system with a strong signal.

Moreover: If they were to target us with such a signal - why would they stop?

Ah, that one's easy. With such a huge output power, they blew every fuse on the planet, and they're still running around trying to fix them.
Find intelligent life on another planet? It's hard enough finding it on our own planet. :-)

Aug 30, 2016
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Aug 31, 2016
What was the nature of the signal? What made anyone think it was not natural?
I think three things, basically – it was a relatively strong signal, it hasn't happened before or since, and there's no obvious verifiable natural explanation.
That information should be supplied in the article.
Yeah, if you check other articles you'll find there's also an image of a graph of the signal that's worth having to scroll past, it should've been supplied too. Here it is: "Figure 1: Figure from Bursov et al. (2016) showing the RATAN drift scan in which the transient was detected."

Aug 31, 2016
Come on, drop the sensationalism, IT IS A NATURAL source, most likely gravitationally lensed.
As others have pointed out, if it were from "aliens" the signal would be more complex and easily distinguishable from the background. The energy requirements to beam out an OMNI directional signal FROM THAT DISTANCE, would surely show you that if intelligence was the source, they would encode intelligent data in the signal. IF it is a linear, directed beam, then EVEN MORE REASON to encode data on it to show it is not artificial.

Just another beat up!!!!!

Aug 31, 2016
IT IS A NATURAL source, most likely gravitationally lensed.

Even from a lensed source an 11GHz signal would be unusual (where do you get that it's likely to be from a lensed effect?)
The authors make it quite clear that we shouldn't consider an intended transmission as most likely cause.

the signal would be more complex and easily distinguishable from the background

Let's just speculate for a second that it was a signal (apart from "we don't know how aliens think so we don't know how they signal each other").
Maybe it was a complex signal and they're just assuming that others aren't as backwards as we are in picking it up? (i.e. they are targetting at intelligences greater or equal to theirs...not necessarily at intelligences as low as ours).
In this case the SNR argument also doesn't hold because to them the SNR may be very much OK.

Aug 31, 2016
" (1) They decide to broadcast in all directions. Then the required power is 1020 watts, or 100 billion billion watts. That's hundreds of times more energy than all the sunlight falling on Earth, and would obviously require power sources far beyond any we have.
(2) They aim their transmission at us. This will reduce the power requirement, but even if they are using an antenna the size of the 1000-foot Arecibo instrument, they would still need to wield more than a trillion watts, which is comparable to the total energy consumption of all humankind "

If it so difficult as it sais, it means Fermi paradox doesnt make sense

Aug 31, 2016
(2) They aim their transmission at us. This will reduce the power requirement, but even if they are using an antenna the size of the 1000-foot Arecibo instrument, they would still need to wield more than a trillion watts
This seems plausible.
it's hard to understand why anyone would want to target our solar system with a strong signal
Well we've been able to detect hundreds of planets after only a few years of looking. We can assume they know our planet is here and that it is inhabited, and even that we are just now building orbital structures and sending out probes throughout the system.

And even though our normal em chatter is too weak for them to detect, they would assume we could detect a targeted signal, and we might be looking.

So they sent out a ping.

I suggest we make no sudden moves.

But we should begin preparing by spreading humanity throughout the system and making it as difficult to eradicate as possible.
Cont>

Aug 31, 2016
Any lifeform advanced enough to ping us in such a manner has probably transitioned to a machine singularity. Communication among its components would be directed and very efficient and therefore the fact that we see a signal could not be incidental.

The only reason machines would want to communicate with us animals is to ascertain if we were a threat or not. And by threat I mean spreading virally and consuming resources in unacceptable quantities.

And the only reason we would do this is that we have somehow thwarted the transition.

And the only way this could happen is if we failed to conquer the religions which make us reproduce and conquer without limit.

I have to believe that we are typical of most any animal intelligence that developed the means to conquer its environment but not its growth rate. And a singularity might be concerned that the cultures which typically emerge to deal with this dichotomy might prevail.

Aug 31, 2016
This made me think of the article from last week

"First test of Breakthrough Starshot interstellar probe highlights likely damage due to gas and dust"
http://phys.org/n...hts.html

-and of the method being developed to propel it;

"Philip Lubin, Univ. of California Santa Barbara, DEEP IN Directed Propulsion for Interstellar Exploration"
http://livestream...05034354

-which is a scalable space-based laser phased array system. Dr Lubin says that an array something like 200x the mass of the ISS could power a shuttle-sized craft to mars in a few weeks, and could also be detected over huge distances.

I wonder if theres any way to know whether this signal at 11 GHz frequency was coherent or not.

Sep 01, 2016
We can assume they know our planet is here and that it is inhabited


Why?

Sep 01, 2016
According to a statement just released by the Russian Academy of Sciences, the signal was most likely from the Earth.

https://www.sao.r...tnikova/

Sep 01, 2016
We can assume they know our planet is here and that it is inhabited


Why?
Well we can assume that a civilization which can build megastructure transmitters in space for pinging us with 11 GHz signals would also be able to build telescopes of similar size, with corresponding sensitivity.

We can already discern the composition of planetary atmospheres. We can already link up several instruments around the planet to create virtual telescopes.

And we can assume that we will have arrays in space in independent solar orbits, 1000s of miles square, all linked and looking at planets around other stars.

We will be able to detect the products of industry in their atmosphere. We will be able to see ISS-sized objects in orbit around their planets both directly and by the perturbations they create.

And if they are pinging us we can assumr they already possess such tech.

Sep 01, 2016
You really need to watch this vid which I posted above

"Philip Lubin, Univ. of California Santa Barbara, DEEP IN Directed Propulsion for Interstellar Exploration"
http://livestream...05034354

-which may explain some of what we are on the verge of doing.

Sep 02, 2016
Well we can assume that a civilization which can build megastructure transmitters in space for pinging us with 11 GHz signals would also be able to build telescopes of similar size, with corresponding sensitivity.


That's assuming it is just as easy to build such a telescope as it is to build such a transmitter, that the laws of physics don't get in your way.

We can already discern the composition of planetary atmospheres. We can already link up several instruments around the planet to create virtual telescopes.


By inference from spectral analysis. You have to remember that the signal that reached us would have been launched 100 years ago, and at that point our radio signals had not reached their system. They would have been looking at us as we were 200 years ago, before the industrial revolution that would have given them any chemical signatures of intelligent life.

So did they just randomly ping one planet out of billions?

Sep 02, 2016
And if they are pinging us we can assumr they already possess such tech.


Again, thanks to the finite speed of light, we're hearing them in the past, from a time they were seeing us even further in the past. Even if they had the tech, they could not have seen the ISS or industrial gasses in our atmosphere because none were there.

So how did they know to signal us instead of any other planet around? With the sort of energy it requires, even a highly advanced civilization wouldn't just ping some distant and unremarkable rocky planet for fun.

Sep 02, 2016
By inference from spectral analysis. You have to remember that the signal that reached us would have been launched 100 years ago, and at that point our radio signals had not reached their system. They would have been looking at us as we were 200 years ago, before the industrial revolution that would have given them any chemical signatures of intelligent life
The industrial revolution was in full swing 200 years ago.

"The Industrial Revolution was the transition to new manufacturing processes in the period from about 1760 to sometime between 1820 and 1840."

-So the gases were most certainly there. And as I say the development of technology must be highly predictable once an animal intelligence begins the journey.

And so we should have expected a ping about now from an entity at that distance.

Thanks for the confirmation.

Sep 02, 2016
Plus we've made massive changes to the ecosphere with agriculture, construction, and war. The tech I described could probably spot the unnatural expansion of deserts, deforestation, agriculture and so forth, and predicted the course of our development.

This is just speculating with an extrapolation of future tech based on what know at the present.

So knowing far more about potentials for intelligent life, they were monitoring our system with its similar star and blue-green planet full of higher lifeforms, and they smelled smoke.

Sep 02, 2016
"That is where the Luvoir telescope comes in. With a 10-meter aperture, it should be possible to detect the spectroscopic signatures of life—ozone, oxygen, water, carbon dioxide, methane—in the atmospheres of exoplanets orbiting in the habitable zones of their stars, where water can exist in its liquid state, says Clampin... The concept calls for "another order of magnitude" of contrast above that of the WFIRST, instrument, which is being designed to provide high-contrast imaging and spectroscopy of exoplanets. With that capability, the Luvoir observatory will be able to survey hundreds of stars, looking for the estimated 16% of exoplanets that lie in the habitable zone, and zeroing in to look for biosignatures."

-And thats just one.

"Concepts today are based upon Fourier Telescopy (several apertures phased together sort of like an interferometer or a star nulling telescope)."

http://www.citize.../tpf.gif

Sep 02, 2016
The only scientific certainty is global warming.
http://www.npr.or...-vulcans

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