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."

Comments

Surprising

[FeatureBug]

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.

Re:Surprising

[Ilgaz]

Broadband wasn't common in 1999. Now they figure aliens must have upgraded too. ;)

Re:Surprising

[smaddox]

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.

Re:Surprising

[Yvanhoe]

No ressource was wasted. I suppose it takes more CPU cycles to check for both narrow and broad signals. The SETI project started by trying to have the lowest CPU usage possible and even by checking signals in a single wavelength in all the sky, it required the SETI@home project : touted as the biggest computation of all human history. Now they apparently are near completing their initial goal of checking for signals in the hydrogen wavelength, so they propose to use more power to check other forms of possible signals.

Yes but

[negRo_slim]

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.

Re:Yes but

[vertinox]

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.

Re:Yes but

[FlyingSquidStudios]

The proven existence of intelligent extraterrestrial life will have a profound effect on a lot of people's core religious beliefs. That alone will have a major effect on society and it might just turn a few people away from their outdated superstitious beliefs. I consider that a tangible benefit.

Re:Yes but

[Stan Vassilev]

The proven existence of intelligent extraterrestrial life will have a profound effect on a lot of people's core religious beliefs. That alone will have a major effect on society and it might just turn a few people away from their outdated superstitious beliefs. I consider that a tangible benefit.

Sure, finding alien life will have a lot of impact. The thing is SETI won't do that, at least as far as basic physics and math is concerned.

But of course, it may end up replacing out outdated superstitious beliefs, and replacing them with more modern superstitious beliefs, such as trying to catch alien radio on our satelites. The parallels between doing this, and an old-school prayer to God are quite ironic.

Re:Yes but

[Memroid]

Yes, but just think of how many more crazy religions it would spawn...

Re:Yes but

[Sanguis Mortuum]

I wonder what the carbon footprint of Seti@Home is...electricity doesn't just grow on trees you know...

we'll never find any signals

[Anonymous Coward]

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

[Free the Cowards]

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.

A terrible analogy

[no reason to be here]

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.

Ironic

[Randall311]

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.

Re:Ironic

[Ransak]

The concept of SETI is to look for radio signals that have been intentionally directed toward us (ie, not stray signals).

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.

Re:Erm...

[MagdJTK]

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.

Highly Debatable

[Crazy Taco]

The proven existence of intelligent extraterrestrial life will have a profound effect on a lot of people's core religious beliefs. That alone will have a major effect on society and it might just turn a few people away from their outdated superstitious beliefs. I consider that a tangible benefit.

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).

That's progress, of a sort

[Animats]

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?