SETI Researcher Quashes Signal Rumors 379
brainstyle writes "According to Dan Wertheimer of SETI the whole ET signal excitement is more hype than science. I told myself it was in all likelihood nothing special, but I'm still disappointed. Darn."
Maybe not radio? (Score:5, Informative)
c == c (Score:5, Informative)
Correct link (Score:2, Informative)
http://news.bbc.co.uk/2/hi/sci/tech/3621608.stm [bbc.co.uk]
see the 2 in the URL ? that denotes US based servers (bbc world edition) if its a 1 its UK servers, great and superquick for the UK but as most of the traffic here is US based its better/quicker to use the designated servers for that area
Although (Score:5, Informative)
If they have found an interstellar signal in this frequency, and it isn't artificial, will we have to revise our understanding of astrophysics? My understanding is that this can't be regular white noise. Maybe it's from our solar system (a naturally occuring local signal rather than interstellar). Or maybe it's something new.
Re:lasers (Score:3, Informative)
Not quite (Score:4, Informative)
No, it's exactly the opposite. There is very low absorption on this frequency, which means the signal will propagate farther than in other frequencies.
will we have to revise our understanding of astrophysics? My understanding is that this can't be regular white noise.
From what I have read, it's a "marginally regular" white noise. That is, it has a shape that's somewhat unusual to find in noise, but not really impossible, just low probability.
Re:lasers (Score:5, Informative)
1. They know we're here and are making a concerted effort to attempt contact us. This means they can't be more than a few light years away, and have already picked up OUR radio waves, meaning odds are we can hear their radio too.
2. They had to know that there was a habitable world here long enough ago to send a signal here on the random chance that there's somebody here to notice. (i.e. they live far enough away that when they sent the laser message, they couldn't know wether or not anybody was here to pick it up)
3. They missed a reciever and hit us by blind luck.
This would also limit us to detecting civilizations advanced enough to have already detected us, and have lasers with narrow enough beams that it's still coherent and good enough aim to still hit us accross great distances.
Non-coherent broadcasts like radio, on the other hand, travels in all directions, and would be expected to be used by civilizations less advanced than us, so we could detect nearly any industrial or better society (assuming we could resolve the signal and recognize it as a signal). Looking for this, we can detect any civilzation, wether they're looking for us or not.
Lasers are easier to detect if they get to us, but radio is much more likely to get to us.
Have we been so primed by TV and movies to expect fantastical aliens that we don't think that we may end up finding the technological equivalent to ourselves fifty or a hundred years ago?
TheReg says that it is not (Score:1, Informative)
here [theregister.co.uk]
Re:Cover-up conspiracy theories (Score:1, Informative)
Or, they're trying to follow their own principles. See the Declaration of Principles Concerning Activities Following the Detection of Extraterrestrial Intelligence [seti.org]. The whole thing basically takes the attitude that we can say whatever we want about whatever we saw, except that we think it might be aliens. Even if we think it might be aliens. Only when it can be "confirmed as indicating the existence of extraterrestrial intelligence" do we say 'they're out there.'
From the horse's (Score:5, Informative)
Unfortunately, reporters, editors and scientists often work at cross purposes. Reporters want to sell stories, editors want to sell magazines, and scientists want the public to hear about their research. When the science won't sell the story, there is often some creative writing that goes on.
That said, I was both misquoted and quoted out of context in the New Scientist article. The crux of the issue is that there really isn't much chance that the "signal" is actually extraterrestrial or even real. The point I was trying to make to the "New Scientist" reporter was that the combination of a stable frequency between observation and the rapidly changing frequency during an observation meant that it was unlikely that it was real, and that it was likely to be a spurious signal due to noise or interference. I reiterated that several times.
I don't know how that got misinterpreted to the point where the article claims I said the signal was unlikely to be interference or noise.
We don't have any plans for reobservation or monitoring, and I'd give 1000:1 odds that there's nothing there.
Re:I'm not usually one for conspiracy theories but (Score:3, Informative)
Paul Horowitz is a physicist at Harvard who's primary claim to fame is being one of the co-authors of The Art of Electronics [artofelectronics.com]. The other author being Winfield Hill.
Paul is a damn smart guy, is pretty funny, and has an encyclopedic knowledge of electronics. I took the Physics 123 class with him and Tom Hayes at Harvard about 5 years ago so I have some sense of his intellect.
His primary research interests are with SETI, and he has old/surplus electronics from the projects META and BETA, among others in his office. He once popped off a Motorola 68000 processor from one of those project boards to loan me for a side project with the class (instead of using the 68008's that are employed toward the end of the course), and he called it "the DIP that ate Chicago" because it's so damn huge.
Since his research involves primarily electronics and the engineering aspects of building large arrays of radio receivers for SETI projects, he referred to himself as a "fallen physicist". He even called me that too because at the time I had physics undergrad degree, but was working at an engineering lab at MIT. (Of course now I'm back in physics grad school ;-) )
So anyway, I get the impression from him that he really knows what he's talking about, and I would tend to trust his scientific judgement about his research project. Now if you assume he's specifically lying or covering up, that's another story. But from a scientific point of view he knows what he's talking about.
Re:From the horse's (Score:4, Informative)
This candidate is still the best scoring candidate that we have. That doesn't make it likely that it is ET. If you find a penny, the likelyhood that it will turn into a hundred dollar bill is small.
At some point the telescope will swing past this point again. If we don't see anything at that point, this whole discussion will go away. If we get the chance, (right now we don't have any allocated telescope time and we don't know when we will get any), we might swing the telescope that way just to lay this to rest.
NEW COMMENT FROM SETI.ORG (Score:3, Informative)
Alas, this story is misleading. According to Dan Werthimer, who heads up the Berkeley SERENDIP SETI project, this is a case of a reporter failing to understand the workings of their search. He says that misquotes and statements taken out of context give the impression that his team is exceptionally impressed with one of the many candidate signals, SHGb02+14a, uncovered using the popular SETI@home software. They are not.
This signal has been found twice by folks using the downloadable screen saver. That fact resulted in the Berkeley team putting it on their list of 'best candidates'. Keep in mind that SETI@home produces 15 million signal reports each day. How can one possibly sort through this enormous flood of data to sift out signals that might be truly extraterrestrial, rather than merely noise artifacts or man-made interference?
The scheme used is simple in principle (although the technical details are complex): SETI@home data come from a receiver on the Arecibo radio telescope that is incessantly panning the sky, riding "piggyback" on other astronomical observations. Every few seconds, it sweeps another patch of celestial real estate, and records data covering many millions of frequency channels. Some of these data are then distributed for processing by the screen saver. By chance, the telescope will sweep the same sky patch every six months or so. If a signal is persistent - that is to say, it shows up more than once when the telescope is pointed at the same place, and at the same frequency (after correction for shifts due to the motion of the Earth) - then it becomes a candidate. Of course, being persistent doesn't mean that the source is always on, only that it is found multiple times.
In February of this year, Werthimer and his colleagues took a list of two hundred of the best SETI@home candidate signals to Arecibo and deliberately targeted that mammoth antenna in the directions to which the scope was pointed when they were found. Once subjected to this closer inspection, all but one of these signals failed to show. That disqualifies them from being claimed as true detections of a persistent signal. The one that was found again, SHGb02+14a (the subject of the New Scientist article), will no doubt be observed yet again, but according to Paul Horowitz, who heads up the Harvard SETI efforts, the statistics of noise make it fairly likely that at least one of the candidates observed in February would reappear, even if all these signals were simply due to receiver fluctuations.
The article remarks on the strong drift of this signal, which it describes as puzzling. Of course, many terrestrial sources of interference, and in particular telecommunication satellites, show strong drifts due to changing Doppler effects as they wheel across the sky. (Incidentally, the technically inclined will want to note drift due to a planet rotating like Earth would be 0.15 Hz/sec, not the 1.5 Hz/sec mentioned in the magazine.) As for the distance of 1000 light-years claimed in the article's title, there is clearly no evidence supporting this number, other than the lack of known nearby stars in the beam.
The bottom line is that an experiment like SETI@home always has a candidate list, a table of those signals that look most promising. Indeed, you can find the current versions of this list on their web site. However, there is a great deal of difference between a candidate, and a convincing signal. If any of the major SETI experiments being run by the SETI Institute, by the Berkeley group, the folks at Harvard, or the Australians or Italians, discovers a signal that they think is of extraterrestrial origin, they will immediately take steps to confirm this, both with their own scientists and with observers at other
signal "drifting" (Score:3, Informative)
First of all, it's doppler shift. Amateur radio operators deal with doppler shift in radio signals when operating amateur satellites. Basically, when either a transmitting station or receiving station are in motion, the transmitted signal will appear lower or higher in frequency at the receiving station, depending on whether the stations are moving closer together or further apart.
It was suggested in the article that the cause of the "drifting" would be due to planetary motion
Here's the problem with that assumption: It assumes that the aliens are intending earth as the recipient of the signal.
It's most likely that the subject signal is being pointed somewhere else and intended for someone else... not us.
It's important here to point out that doppler shift will vary between any two points. SO
Additionally, going on the theory here that we are not the intended recipients of the signal... and thus perhaps not directly in the path of the strongest part of the signal, also explains why reception was a bit weak here at earth.
Armchair scientists unite!