Any sufficiently advanced technology is indistinguishable from noise. I remembered hearing this in school so I searched and found this paper. [eva.mpg.de]
As I understand SETI has always been searching for narrowband signals in the past. But our technology is moving toward spread spectrum signals for more efficient use of bandwidth, making our transmissions appear more like noise to anyone who doesn't know the encoding scheme. Aliens could be doing/have done the same. So good luck, scientists!
We should better look for industrial uses of RF like microwave ovens and such. At least we will know how long it takes the other guys to warm up yesterdays dinner.
Well, if there's actually any such thing as usable "wormholes" (dubious, I know) and assuming there's an emission at the ingress/egress then there would be a time correlation between ships entering and exiting. Maybe they should be looking for unusual correlations between different, widely spaced pixels instead of signals from a point source. At the very least they might discover some kind of neato naturally occurring entangement-based phenomena.
We're far enough away from any likely candidate systems that we would only pick up very high power omni-directional signals - in other words, intentional beacons. Such a beacon is unlikely to be highly encoded (though there might be an associated signal that *is* highly encoded, and to which there is a pointer in the beacon signal). In other words, we don't have to worry too much about the Kolmogorov complexity of extra-terrestrial signals, because we won't be "overhearing" anything.
(This is not my field, but) I think a good way to state it is that if you are sending a data stream that has any order or predictability to it, you are not using your communication resources most efficiently. Surely the aliens wouldn't have truly optimal efficiency, but as they get smarter they will make it harder and harder for us to find them. (Ha. Maybe the efficiency is a happy side-effect.)
Help me out, I don't know the physics: Does the signal vs noise issue hide the fact that you are using a powerful transmitter to cross large distances? Power on a channel that has no naturally occurring phenomenon to make it would seem to be a dead giveaway for intelligent communication.
The cosmic microwave background is everywhere, at all frequencies. Any signal you send has to be stronger than this.
But wait, if you use spread spectrum signals, you can actually receive a signal with a power spectral density that's lower than this noise floor! So there could be alien signals lurking below the CMB, but we have no chance of finding them without guessing their code. And as the codes get more complex and more efficient, they become more impossible to guess.
SETI as designed is incapable of even detecting and decoding something akin to the Arecibo message, so I'm always puzzled at how they think they're actually going to know when they have hot data for real. I applaud the effort but I've always felt it was more of a feel-good activity for people to join in on. Hmm....
Any sufficiently advanced technology is indistinguishable from noise. I remembered hearing this in school...
Well, to be more precise, it follows as an implication of:
1) Sufficiently advanced technology is indistinguishable from magic. (Clarke's 3rd Law.) 2) Maximally compressed data is indistinguishable from noise. (Theorem in information theory.)
A sufficiently advanced civilization will ("magically") hit the theoretical compression maximum, and that will look like random noise. (Anyone's head hurting yet?)
I guess we will also in 100 years or so realize that we emit nothing but noise, and short distance one for that matter (Wi-Fi, some future gen). So, if we want to be visible to potential neighbors, we must establish "pulsing station", which emits something intelligent and easily detectable, like prime numbers. But it is unlikely it will be old fashioned radio signal. It is probably hard to detect from such distances because it is destroyed by objects on its way (stars, galaxies, small objects, gas, whatever). Maybe neutrinos, such pulse could pass trough everything on its way, and maybe there is way to pickup that broadcast somehow on the other side (if there is, they will know how). So, maybe it is just to early for this sort of projects, there is homework on inter-galactic broadcast to do, and one that actually make sense, not analog TV.
According to Claude Shannon... (Score:5, Interesting)
Any sufficiently advanced technology is indistinguishable from noise. I remembered hearing this in school so I searched and found this paper. [eva.mpg.de]
As I understand SETI has always been searching for narrowband signals in the past. But our technology is moving toward spread spectrum signals for more efficient use of bandwidth, making our transmissions appear more like noise to anyone who doesn't know the encoding scheme. Aliens could be doing/have done the same. So good luck, scientists!
Re: (Score:2)
We should better look for industrial uses of RF like microwave ovens and such. At least we will know how long it takes the other guys to warm up yesterdays dinner.
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Well, if there's actually any such thing as usable "wormholes" (dubious, I know) and assuming there's an emission at the ingress/egress then there would be a time correlation between ships entering and exiting. Maybe they should be looking for unusual correlations between different, widely spaced pixels instead of signals from a point source. At the very least they might discover some kind of neato naturally occurring entangement-based phenomena.
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Re:According to Claude Shannon... (Score:4, Interesting)
But would such "noise" get past a zipf analysis? (http://en.wikipedia.org/wiki/Zipf's_law). Even compressed and encrypted data doesn't lose order.
Re:According to Claude Shannon... (Score:4, Informative)
If you take truly compressed data, which resembles uniform noise, you will see a uniform distribution, not the one described in Zipf's law.
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Help me out, I don't know the physics:
Does the signal vs noise issue hide the fact that you are using a powerful transmitter to cross large distances? Power on a channel that has no naturally occurring phenomenon to make it would seem to be a dead giveaway for intelligent communication.
Re: (Score:1)
Re: (Score:2)
http://en.wikipedia.org/wiki/Cosmic_microwave_background_radiation [wikipedia.org]
It may be at all frequencies, but it would seem to be a meaninglessly low floor at most.
SETI is flawed though... eg Arecibo message (Score:4, Insightful)
SETI as designed is incapable of even detecting and decoding something akin to the Arecibo message, so I'm always puzzled at how they think they're actually going to know when they have hot data for real. I applaud the effort but I've always felt it was more of a feel-good activity for people to join in on. Hmm....
Re:According to Claude Shannon... (Score:5, Informative)
Any sufficiently advanced technology is indistinguishable from noise. I remembered hearing this in school ...
Well, to be more precise, it follows as an implication of:
1) Sufficiently advanced technology is indistinguishable from magic. (Clarke's 3rd Law.)
2) Maximally compressed data is indistinguishable from noise. (Theorem in information theory.)
A sufficiently advanced civilization will ("magically") hit the theoretical compression maximum, and that will look like random noise. (Anyone's head hurting yet?)
My head is hurting... (Score:3, Funny)
But only because you've blown my mind!
Re:According to Claude Shannon... (Score:5, Funny)
Any sufficiently advanced technology is indistinguishable from noise.
So those noise making things that we heard at the World Cup actually were a sign of intelligence?????
Re:According to Claude Shannon... (Score:5, Insightful)