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

[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

[Memroid]

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

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.

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?