Does SETI have the technology to detect artificial neutrino signals? Radio waves seem like smoke signals
Short answer is “no.”
The long answer is I don’t think that they even own the technology to detect radio signals, either.
The piggyback on other radio telescopes, and sift through the data to try to find signs of artificial signals.
We, as a species, barely have the ability to detect neutrinos at all. I am sure that Seti could look at the data that we do receive, but it is so little that there is no way that any signal could be detected, even if it were there.
The best neutrino detectors we have only detect a miniscule fraction of those that go through it. Any signals using them would be undetectable with our current neutrino detection technology.
If we improve that technology, and start detecting an appreciable fraction of those that stream through us at every moment, then I am sure that SETI would be interested in sifting through that data as well.
It’s extremely difficult to detect neutrinos, whether from natural or artificial sources, because the overwhelming majority of them simply pass through stuff without affecting it.
Then it seems like a communication system based on neutrinos instead of radio waves would be efficient and secure. Let’s go Stanford and MIT.
Only two problems with that.
Creating them, and detecting them.
Everything else is gravy. 
But, in all seriousness, if we were able to create and detect them, then they would be a better medium for interstellar communication that radio, you are right on that.
We can create little bits of them at a time in accelerators, but that would be a very inefficient means of transmitting information. There may be ways of ramping that up, but with our current understanding of how things work, there’s no easy way to do it.
We don’t have any ways of detecting them efficiently, or good ideas on how to ramp that up either.
Maybe we will figure something out, but I wouldn’t hold my breath on that one.
Neutrino communications might be secure, but they’d be the exact opposite of efficient. To get any decent bandwidth out of them, you’d need to use an entire ocean as a detector. And when your communicator is that big, just whom are you communicating with?
I am not a physicist, nor do I play one on TV. But I would argue that the biggest problem that radio waves have in term of their use for interstellar communication is shared by neutrinos.
They both travel at light speed, and light speed is just crazy slow for use in interstellar communications.
I suppose if it turned out that it was easier to set up a super-tight beam of neutrino transmission than a super-tight beam of radio transmission that would provide some sort of advantage for neutrinos, but neutrino communication would still be crazy-slow. And of course if our current understanding of physics is correct and information simply cannot be transmitted at anything beyond light speed, well, that’s all we’ve got.
One step that has been made recently is to reduce the size of neutron detectors by several orders of magnitude. Small and light enough that they could, for example, be put on spaceships. However, those are no more efficient at actually detecting them, so you’d have to generate a huge pulse of neutrinos to make sure the signal gets to the receiver. And unless you find a way to make and detect different frequencies of neutrinos or make the pulses highly directional, you’re going to have problems with more than one neutrino transmitter in use at the same time.
All communications are covered by Shannon’s Law for communicating in a noisy channel.
Basically your information rate is constrained by your bandwidth times your signal to noise. Neutrinos as a communication mechanism would appear to be facing a seriously uphill battle. The rate you can detect them at constrains the bandwidth. The energy resolution you manage forms part of the signal to noise, as does the background of other neutrino sources.
The range of neutrino energies detectors look for is pretty wide. From MeV to PeV. But the detection rates are minuscule. Maybe 1 every two weeks for TeV neutrinos. And PeV ones, so far none. And we need to reliably detect our communications against the background noise of the operating universe. This signal to noise constrains our information rate, we can communicate with signal under the noise but the information rate drops further. Communication technology based upon current neutrino detection technology, and assuming an ability to generate neutrinos at will of similar power to a major cosmic source (destroying a star for each bit of information) might get you a mechanism to communicate across the galaxy with a information rate of maybe a byte per year - if you were lucky.
ATM we have a much better chance of visually seeing a star going Nova than seeing its neutrino flux reliably.
If you want to communicate over stellar distance I think the approach taken by Trurl and Klapaucius, who arranged a group of stars into a nice patter to advertise their services might serve better.
Since neutrinos have almost no interaction with matter, they’d be very good at penetrating great distances in the universe, through clouds, dust, interstellar medium, intergalactic medium, and so forth. But if you want to make long distance communication radiation penetrate even better, you should use radiation that has absolutely no interaction whatsoever. Maybe we could communicate with idea waves, or notion particles, or intention radiation.
Why would interstellar communication need to be secure?
I suppose in our would we worry about snooping on the radio bands we use for various communications – stalkers, nosy neighbors, criminals who want information on us, governments who don’t have the common people in mind and only care about power for its own sake (which is all of them open your eyes, sheeple !!!1!!)
Ahem, channeled conspiracy nuts for a second there.
I suppose if you suspect the civilization in question is a Star Trek or Star Wars-like civilization, and needs to conduct devious trade and plan warfare across vast distances, then security is a thing. But without evidence of the civilization, how can we make that assumption.
Also, as was mentioned above, why neutrinos? The most obscure technology you could find is how we should communicate? "Cause alien civilizations are awesome. So we got be awesome too? So obviously, make the transmission and detection as difficult as possible?
So, from the big bang, there’ a background of microwave radiation, right? So, why do we, on Earth, use that bandwidth for communication? No one will ever listen in on my private communications, with all of that static. Wait …