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SETI@Home Adds New Search Method
Adam Korbitz writes to point out that SETI@Home has added a new algorithm for use in evaluating signals from outer space. It's called "Astropulse," and they've made the scientific details available. Quoting:
"The original SETI@home is narrowband, meaning that it is listening for a particular radio frequency. That's like listening to an orchestra playing, and trying to hear when anyone plays the note "A sharp." Astropulse listens for short-time pulses. In the orchestra analogy, it's like listening for a quick drum beat, or a series of drumbeats. Since no one knows what extraterrestrial communications will 'sound like,' it seems like a good idea to search for several types of signals. In scientific terms, Astropulse is a sky survey that searches for microsecond transient radio pulses."
I find it slightly surprising it has taken the SETI project how many years to start checking broadband as well as narrowband signals. All those years spending a fortune in resources but only checking narrowband seems rather a waste of time. I would have been checking all sorts of broadband signal types from the very beginning.
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Haven't we already covered this? The cost in electricity for them to use my "unused" resources is not worth it for SETI which offers and most likely will never offer any tangible benefit to our society.
On the Oregon Cost born and raised, On the beach is where I spent most of my days
As the information in a radio signal approaches the Shannon limit, it becomes indistinguishable from noise to an outside observer. Any sufficiently advanced civilization will have the technology to maximize the information sent in a radio signal. Therefore we will not be able to detect radio signals from other civilizations (except for perhaps a 100-200 year period in their evolution where they use inefficient radio signals)
Except for a huge assumption you're making: that an advanced civilization wouldn't want to broadcast a distinctive, easily decoded, narrowband signal. Perhaps they might want to do it to announce their existence to the rest of the universe, even though they would have the know-how to sendmuch more efficient broadband signals.
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As a musician and a recording engineer, I feel I must comment on the analogy used.
For someone with a trained ear picking out an A#, or any particular note, shouldn't be all that difficult, especially if that note is tonic, 3rd, 4th, 5th, or other similar high recognizable interval from the tonic. It would be trivially easy for someone with perfect pitch to pick out a particular note.
I suppose the analogy might hold if we compared the prior SETI searching signals to be like a man who is deaf in his right ear turning his left ear away the orchestra to try and determine if the 2nd piccolo is playing sharp on A#, and now, SETI is that same man, facing forward with a brand new hearing aid, merely trying to pick out staccato notes.
my pet machine
I wonder if similar detection rates have been calculated for SETI (e.g., assume ET having a transmitter of 1 MW, at what distance would you still detect anything? And how many life supporting planets are in that range? ) This will depend a lot on the parameters in your Drake's equations, but they should at least give some order of magnitudes. I remember reading some skeptic article several years ago, which claimed that even with optimistic estimates, the chance of detecting anything would be absolutely zero.
Until that time, I rather waste my computer cycles on the LIGO data (Einstein at home) or one of the various medical applications (e.g. Folding at home), which produce scientific results today.
karma police: arrest this man, he talks in maths; he buzzes like a fridge, he's like a detuned radio. [radiohead]
Does anybody else find it ironic that we are looking for intelligent extra-terrestrial communications on the very same frequency that we (an intelligent species) are prohibited from transmitting on? The 1.420 gigahertz frequency was chose (I believe) because of the hydrogen line. It would seem to me that a more effective methodology would be to do a spectrum sweeping search. The odds of any intelligent species transmitting on just one frequency are unlikely enough. Combine that with the fact that we are only listening on one frequency. Now we can compare finding a needle in a haystack as trivial in comparison.
The Voyager Interstellar Mission would seem to show that at least one civilization is not so paranoid as to be prevented from sending out an invite to a home planet. The golden record inside both Voyagers include directions to Earth.
I don't fucking care & refuse to show any respect, or even read anything you've said after it.
This is why we need people to be more rational.
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His point was that people can be good without being religious. And of course people can be nasty and religious at the same time.
...go fuck yourself.
Your posts have done a lot to back up his claim.
Yes, but is there any alien life? Certainly there's been no evidence of any, though you talk as though it certainly, and inevitably, exists. It sure sounds like you are the one making assumptions and promoting a faith based argument!
And as for this changing anyone's beliefs, that's highly debatable. Christian author CS Lewis wrote a trilogy in the late '40s that imagined intelligent life to be on both Mars and Venus. He was a noted apologist and theologian for the Christian faith, and he had no problem with considering the existence of extraterrestrials. (Note: The starting book of the trilogy was called Out of the Silent Planet).
Beware of bugs in the above code; I have only proved it correct, not tried it.
SETI, as primarily currently pursued, is unlikely to find anything. I sum up my perspective, "We don't talk to nematodes and *they* don't talk to us." It is useful to consider the difference in intellectual capacity between humans and nematodes is far less than that between Matrioshka Brains and us.
Most advanced extraterrestrial civilizations are going to be far far ahead of us. At the point where they have constructed Matrioshka Brains. The intellectual capacity of an MBrain is roughly a trillion trillion times that of a human brain. They can simulate the history of entire humanities in seconds. We are simply not of interest to them.
There are 3 ways to detect MBrains.
1. Stellar occultations (similar to some of the exoplanet searches now being done).
2. Gravitational microlensing studies (also being done).
3. Large scale mid-to-far IR surveys looking for bright IR objects that do not appear to be visible (not being done because our far IR detectors are extremely poor and not particularly sensitive; and they must be operated from space so they are $$$).
The observant will note that none of these involve using computer cycles for the analysis of radio wave noise. The astronomer geeks will notice that long term backyard surveys searching for exoplanets using variations in stellar brightness might either capture candidate stars with exoplanets or perhaps an occasional gravitational microlensing event or maybe an MBrain traveling through the galaxy on its way to the nearest carbon white dwarf star (because they need more carbon for extreme nanotech) or a stellar gas nebula for a fueling pit stop. The extremely astute might notice that should sufficient numbers of these be discovered then there might be another explanation for all of the "dark matter" which doesn't result from the physics of the universe but from the natural activities of intelligent life. (Perhaps making the theoretical physicists extremely unhappy.)
It is also the case that to scan large fields of stars for variations in brightness and separating the normal variable stars from those which are "unusual" would not be a small use of ones spare computer time.
Well, that's progress. I've criticized SETI@Home for looking for "carriers" signals with a large fixed-frequency component. They need to get beyond that. AM and FM signals have carriers (Analog TV is AM video with an FM audio subcarrier), and as a result, 80% of the signal energy is wasted. None of the more modern digital transmission systems have strong carriers.
The more efficient a transmission system, the more it looks like white noise if you don't know how to decode it. If there's some big repetitive component like a carrier, or the horizontal and vertical retrace intervals in analog TV, it's inefficient. The FCC wouldn't approve any new transmission system which wasted bandwidth like that, and the old ones that do are being phased out.
So SETI systems that look for carriers are looking for civilizations advanced enough to generate high-power RF signals, but not advanced enough to use more efficient digital modes. Our civilization went through that period in under a century. It's also fairly clear that nobody in our stellar neighborhood is continuously sending a strong RF carrier in our direction; that's been looked for.
Question: can the new SETI algorithm pick up an HDTV broadcast station?