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SETI@Home Adds New Search Method
Posted by
Soulskill
on Sun Jul 27, 2008 12:19 PM
from the look-for-interstellar-torrents dept.
from the look-for-interstellar-torrents dept.
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."
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SETI@Home Adds New Search Method
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Surprising (Score:5, Insightful)
Re:Surprising (Score:5, Funny)
Broadband wasn't common in 1999. Now they figure aliens must have upgraded too. ;)
Parent
Re:Surprising (Score:4, Interesting)
They chose 1420 megahertz for a good reason:
There is, however, a pronounced minimum in the radio-noise spectrum. Lying at the minimum or near it are several natural frequencies that should be discernible by all scientifically advanced societies. They are the resonant frequencies emitted by the more abundant molecules and free radicals m interstellar space. Perhaps the most obvious of these resonances is the frequency of 1,420 megahertz (millions of cycles per second). That frequency is emitted when the spinning electron in an atom of hydrogen spontaneously flips over so that its direction of spin is opposite to that of the proton comprising the nucleus of the hydrogen atom. The frequency of the spin-flip transition of hydrogen at 1,420 megahertz was first suggested as a channel for interstellar communication in 1959 by Philip Morrison and Giuseppe Cocconi. Such a channel may be too noisy for communication precisely because hydrogen, the most abundant interstellar gas, absorbs and emits radiation at that frequency. The number of other plausible and available communication channels is not large, so that determining the right one should not be too difficult.
Source:http://www.ufoevidence.org/documents/doc252.htm
More recently scientists have considered neutrino signals to be much more likely for alien communications since they can be sent across the universe with minimal signal degradation. The problem is that they are very hard to sense, and even harder to generate as a controllable signal.
Parent
Re:Surprising (Score:5, Informative)
Parent
Yes but (Score:4, Insightful)
Re:Yes but (Score:5, Insightful)
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.
True, but who are you to say what others due with their free CPU cycles?
Personally, I like protein folding, but if other people want to look for alien life with their cycles then its their computer.
Parent
Re:Yes but (Score:5, Insightful)
Parent
Re:Yes but (Score:4, Insightful)
Parent
Re:Erm... (Score:4, Insightful)
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.
Parent
Highly Debatable (Score:4, Insightful)
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).
Parent
we'll never find any signals (Score:5, Interesting)
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)
Re:we'll never find any signals (Score:5, Insightful)
SETI is not searching for accidental transmissions or leakage. SETI is only searching for deliberate beacons being sent by alien civilizations. SETI's techniques cannot detect random radio chatter and are not intended to.
Parent
About Time (Score:2)
Strange that they are only doing that now - haven't they seen Contact?
I'm Going To Be Royally Pissed (Score:1)
Probing... (Score:1)
You now have the option to filter out aliens who might want to probe you.
Use light, not radio waves (Score:2)
If I wanted to send a signal across the universe, I'd use light, not radio waves.
So, why is SETI still limiting itself to searching for signals in the radio spectrum?
A terrible analogy (Score:5, Interesting)
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.
New algorithm... (Score:1)
I got the beat. (Score:1)
Thump...Thump..Thump..
I wonder if they should look for styles of rythms. Dance, hip-hop, etc.
What are the chances? (Score:3, Interesting)
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 [uwm.edu]) or one of the various medical applications (e.g. Folding at home [stanford.edu]), which produce scientific results today.
Priorities (Score:1, Redundant)
Ironic (Score:4, Insightful)
Re:Ironic (Score:4, Insightful)
The SETI line of thought is if another civilization is intelligent enough to understand the Hydrogen Line and the Microwave Window and that another civilization - us - would understand that as well and use it for radio astronomy, the frequency of Hydrogen (1420.40575 MHz) would be the most likely place we would be listening since the universe is mostly made up of it from what we can tell so far.
Parent
Wow, so much SETI love... (Score:1, Offtopic)
If SETI ever detects a real, verified alien signal, as soon as I hear the news, I'm going to drop whatever I'm doing, and rush to see the comments on Slashdot. I can't imagine what the response would be if a project so (apparently) universally hated here actually turned up a positive result.
Not that I run SETI@home, plan to, or expect an actual SETI discovery to happen in my lifetime, if ever. It's just something on my "wouldn't it be funny to watch if..." list.
SETI vs. Glomar Explorer (Score:1)
If Ed Mitchell is right, they're listening for the return of the Mother Ship coming back to Roswell to pick up the survivors, and we'll be lucky if we notice it coming through the Oort Cloud.
My personal guess is more mundane. All that distributed processing power has been harnessed to help Echelon listen for Al Qaeda.
SETI is absurd on the merits, though. If aliens are out there, if aliens are advanced, if Einstein was right and quantum mechanics is righter, why would aliens use something as feeble as the electromagnetic spectrum? They're probably doing something we can't even imagine, like knocking on the walls between universes.
SETI is an extreme misdirection (Score:3, Interesting)
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.
Based upon human usage (Score:1, Funny)
I would guess, based on human usage, that if SETI intercepted an alien signal it would have a 50% chance of being alien porno.
How many more times.... (Score:2)
That's progress, of a sort (Score:5, Informative)
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?
The flaw in the whole concept (Score:1)
For a long time I have looked at SETI as doomed to failure... and not because there isn't any intelligent life out there. Here's my reasoning. In the history of the human race, how long have we had radio? Slightly over 100 years.. that's a tiny portion of our over all development. And we can not say that we will still be using the technology 100 years from now. Just as the horse and buggy was the height of technology, the automobile came along and replaced it... and this would not have been anticipated by people in 1800. So we may be looking at a relatively narrow window for use of this technology. So to go along with this you would have to have intelligent aliens who are at a similar stage in development to us.. not too early as to not use radio waves and not beyond the technology. Consider that there are planets and stars much older and younger than our own, and even on our planet how many waves of life there have been, the odds of finding alien life at just the right level of technology would seem to be unlikely.
"In scientific terms," (Score:2)
Great! (Score:1)