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New Telescope Array Goes Live For SETI
Posted by
Zonk
on Thu Oct 11, 2007 04:16 PM
from the hello-is-there-anybody-out-there dept.
from the hello-is-there-anybody-out-there dept.
The Skinny writes "Today is a historic day for the SETI program. The New York Times reports that astronomers are flipping the switch today on the Allen Telescope Array — 350 antennas, each 20 feet in diameter — which will, among other things, extend the search for extraterrestrial life a thousandfold. From the article: ' There are some 200 billion stars in the galaxy, and a significant fraction of them have planets. Estimates of the number of intelligent civilizations in the galaxy have ranged from one (or none, if you are particularly discouraged about human affairs) into the millions. Dr. Shostak calculated that the full Allen array would be able to detect a signal from as far as 500 light years that is only a few times more powerful than what can now be sent by the Arecibo radio telescope, a 1,000-foot-diameter dish in Puerto Rico that is the world's largest (although it is in danger of being shut down to save money). That translates to about a million stars, which he said was getting into a promising number. Dr. Shostak described the expanded search as looking for the needle in the proverbial haystack with a shovel instead of a spoon.'"
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Submission: Privately Funded Telescope Array Goes Live by Anonymous Coward
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500-fold Increase in Data Flow from SETI Telescope 346 comments
coondoggie brings us an article from Networkworld about a flood of new data for the SETI@home project. We discussed something similar a few months ago when a new telescope array went live. The vast amount of processing power required to handle the new data is prompting the SETI@home team to make a plea for more volunteers. Quoting the press release:
"What triggered the new flow of data was the addition of seven new receivers at Arecibo, which now let the telescope record radio signals from seven regions of the sky simultaneously instead of just one. With greater sensitivity and the ability to detect the polarization of the radio signals, plus 40 times more frequency coverage, Arecibo is set to survey the sky for new radio sources."
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Only 42 installed so far (Score:4, Informative)
At least they got the answer right... (Score:5, Funny)
Parent
Re: (Score:3, Funny)
"That's no space station, Qfitzglb, that's a moon!"
Re:Billions or millions, right? (Score:5, Insightful)
If they spent $100mill on a telescope array, where did the money go? It went to some firms who do that, who in turn paid their employees and their suppliers, who paid their employees, etc. Those employees bought groceries, sent their kid to the dentist, sent their kid to college, bought a new car.. the money flowed through the economy. Assuming a large percentage of the firms and suppliers are in this country, then the money stayed in the national economy.
When the economy is flowing actively, more of those people downstream will be willing to donate their time and money to what you'd probably classify as "good things". When it slows down, or the Government is taking a big chunk at every step as taxes, then they'll be less inclined to do so.
Parent
What about deflation? (Score:5, Informative)
Although I agree with the rest of your comment, I don't think burning money is wasting it. If you destroy currency you are removing it from circulation, which will cause prices to go down due to deflation.
If you truly want to waste money, you should buy something of value to others and destroy that thing. The grandfather post would be right, if one assumes that scientific research has no value. However, that is very seldom the case. Research is almost always valuable, even if it turns up nothing. Negative results are also knowledge. If we find no sign of extraterrestrial intelligence in our search we will know more than we did before about the abundance or scarcity of intelligence in our galaxy.
Parent
Re: (Score:3, Insightful)
If you truly want to waste money, you should buy something of value to others and destroy that thing."
Not at all. Either way, you remove value from the world. Whether in the form of a physical object of a particular value, or in the form of cash (a physical representation of abstract value), your destructive act has the same effect on the wider economy. Which is to say, not much unless it's
Re:Billions or millions, right? (Score:5, Interesting)
The first is that there is a concept of 'best-use'. That is, there are some projects (such as SETI) that some people feel are less worthwhile than other projects. Some people believe that the man-hours and capital used on SETI is wasted because nothing of value is produced by SETI (in their opinion) -- so yes, the money flows through the economy, but on a more worthwhile project, that money would flow through the economy while producing something of value. The money is in effect hoarded, which means that the opportunity to use it for growth is wasted.
The second point has to do with your remark about taxes.
Money paid as taxes also flows through the economy, for the same reason that money put into erstwhile "wasteful" projects flows through the economy. It's a bit of a double-standard to say that money that goes to taxes inhibits downstream spending, since that money is, in a very real way, redistributed to others, whether by government contract, to government employees, or otherwise. The exceptions would be foreign spending, which generally has benefit to the US as well, if less tangible.
If anything, with today's government, money taken out as taxes actually produces more money in circulation, since the US government runs a deficit budget with a cap on borrowing based loosely on government receipts. Every $1.00 given to the federal government returns $1.00 * [1 + (annual debt)/(annual receipts) -- of course, that's financed at an as-yet-undetermined final cost, since who knows what interest rate we'll have to pay on it when we refinance through new debt offerings...
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The parable is better applied with the government in the role of the boy, and the public in the role as the shopkeeper. The government takes the public's choice
Shovel instead of a spoon? (Score:5, Insightful)
Re:Shovel instead of a spoon? (Score:4, Informative)
Study Predicts Trillions Of Planets http://dsc.discovery.com/news/afp/20030922/universe.html [discovery.com]
NASA estimates the number of terrestrial planets to be as high as 30 Billion: http://astrobiology.arc.nasa.gov/news/expandnews.cfm?id=1227 [nasa.gov]
(And both articles are several years old...)
Parent
Re: (Score:2)
Seriously, taking into account the number of stars, the number of planets orbiting the stars, and the span of time that they're likely to be spewing radio waves, the task is monumental compared to any resources that SETI may get.
The number of stars has no effect on the time taken to identify a civilisation. The population density of the galaxy does. It doesn't matter how many stars there are, if every hundredth star system has an earth-like planet, with a life-form that is emitting radio waves, chances a
Alien Telescope Array? (Score:2)
Re: (Score:2)
It's good to know that I'm not the only person to read "Allen Telescope Array" as "Alien Telescope Array".
To be honest (Score:2, Insightful)
There has to be hundreds of thousands of life forms out there (at least). The sooner science finds it, the better.
Re: (Score:2, Interesting)
http://en.wikipedia.org/wiki/Fermi_paradox [wikipedia.org]
Tell me, if there is such a ridiculous high chance of other life, where is it? There is not a single clue of extraterrestrial life and this will be a huge moneypit. Well, that and the moonrace.
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You are overlooking time.
Within the time span of the universe, it is certain there are forms of life that had existed but no longer.
For example, there have been species on this planet that no longer exist.
So what we could fine is a radio wave that was sent out 1000 years ago...or perhaps some species launched a dive that gives off a regular signal as it just travels across space.
The moon race has generated a LOT of revenue, tec
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In other words, it is no more foolish to insist that we are
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Nonsense. Your claim is as fact free and agenda driven as those whom you deride.
We simply don't have enough information to evaluate the scarcity or commonality or worlds that will support life. We don't even
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There is, however, no credible evidence supporting its existence of SETI.
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Re:To be honest (Score:4, Insightful)
It surely does not. It just puts a different spin on it.
Anyone can choose a bad apple and attempt to infer that all apples are bad by it. Doesn't make it any more so...
Parent
See Seth Shostak if you can (Score:3, Informative)
Will we need a new client.... (Score:2)
...or will the new antenna rollout use the same BOINC client [berkeley.edu] as I'm using now?
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I think this shows that you have a grave misunderstanding about how SETI@home, SERENDIP, META, and BETA work and how the are very interrelated. I
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BOINC was designed with the purpose of being a meta client, so if the SETI people are going to make this new stuff under a different BOINC project, all you have to do is add it to your clients, and BOINC will download any necessary processing cores.
I knew about BOINC being a metaclient, as I also run Einstein@home... Just wasn't sure if they'd count it as a different project or not. I remember the switch from the dedicated SETI client a while back...
Thanks for the clarification!
Pfft (Score:2, Informative)
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SERENDIP, META, and BETA are essentially simple FFT processors, with BETA essentially being four 80 million channel analyzers. That is proof that to an astronomer 240 million is equal to a billion. SERENDIP IV (the last one deployed) was a 168 mi
I for one... (Score:3, Funny)
It's so nice when that meme fits without having to be stretched. This certainly is exciting news (about the telescopes too).
I never quite understood how ... (Score:2)
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There are other mutli-telescope arrays, apart from the VLA in New Mexico (made famous by films like Contact) although few are g
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Think of each dish antenna as an element of a single larger antennta
Not just the wrong band, the wrong everything (Score:4, Insightful)
But... lets thing about this logically... (Score:3, Insightful)
Did I mention its not backwards wednesday?
SETI is hopeless (Score:4, Insightful)
I'm in the EE field, specifically wireless/radio communications.
The calculation for path loss is:
Loss dB = 32.44 + 20 log (dist in km) + 20 log (freq in MHz)
Lets take absolute optimal conditions..proxima centauri is roughly 4 light years away. This is roughly 3.78x10^13 km away. One of the most common frequencies monitored is the "hydrogen line" (1420.40575 MHz) since this is the resonant frequency of hydrogen and is more likely to be used by aliens since we'd most likely be looking there.
So, lets fill in the equation:
32.44+ 20log(3.78x10^13)+20log(1420.41)= 367.038 db of loss...
So lets say they are transmitting with a million watts(90dBm), and there is a 60db dish on both ends(huuge dish)...This gives us a receive level of -157.038dBm. This is a good bit below what any normal radio will receive at. The noise floor is certainly higher than this. Now keep in mind this is the very closest star, which I don't think even has any livable planets.
Our galaxy is 70-100 thousand light years across and we are right near the edge. So if you take a star not even close to that distance, say 500 light years (still somewhat close on a galactic scale) then the calculations work out to a receive signal of -198dBm. The equipment doesn't exist to pick the signal out of the noise at levels like that.
God forbid trying to pick the signal out of another galaxy, the nearest being Andromeda. some 2.5 million light years away. Giving Rx signal levels of ~ -273dBm. Safe to say the noise floor is MUCH MUCH higher than this.
I think SETI is a hopeless pipe dream. That being said, I DO think there is intelligent life out there, probably in our galaxy. There are just too many stars with too many planets to think otherwise.
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Sorry, I've forgotten 90% of the EM I learned from 20 years ago, but I don't recall that there's a frequency dependence for transmission in vacuum. Is this the right equation to use?
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Seti is noble. It's good PR. But it's hopeless and doomed to failure even if the universe is teaming with sentient, space-faring life.
Our e
Your calculations are wrong; SETI is viable (Score:5, Interesting)
I assume you think your erroneous application of signal theory leads to that conclusion. More studious and clever people than you have already illustrated the viability of signal reception at these distances, and your analysis is quite simply wrong. Your "EE" expertise has led you astray: when you ask someone who only knows about whales a question about ducks, he talks about whales anyway. Radio astronomy has had these things down for more than 50 years, and you're a day late and a dollar short.
We're interested in obtaining a signal against a background. The antenna temperature, Ta, determines this:
Ta = [(pi^2)/16k] * (W/r^2) * (D1^2 * D2^2) / lambda^2
where
k is Boltzmann's constant
W is the power per unit of bandwidth of the source
D1 and D2 are the diameters of the receiving antenna and (hypothetical) transmitter antenna
lambda is the wavelength
The signal, per the common example, is 1420.4GHz => 21.1cm =
What about the noise temperature of the receiver? A receiver must have sufficiently low Tn, otherwise it's louder than the signal it tries to measure:
Tn-rms = Tn / sqrt(t * Bw)
where
Tn-rms is the root-mean-square value in question
Tn is the noise temperature of the receiver in question
t is the integration time (how long we keep the lid off the photon bucket)
Bw is the receiver's bandwidth
The noise temperature of modern low-noise amplifiers is much lower. A rule of thumb for present-day: 1 Kelvin per GHz, plus 1 Kelvin, so 2~3 Kelvin for this LNA, and there are lower noise devices available for a price, but only to a point. The cosmic background noise is larger than the receiver noise!
Let's combine them and rearrange, and see just what kinds of power and distance we need:
r = (pi/4) * sqrt(W / k*Tn) * (D1 * D2 / lambda) * (t * Bw)^.25
Suppose we have a 50kW transmitter, use the 300m Arecibo dish to transmit and receive, use a bandpass of 1Hz (this is reasonable), and an integration time of about 20 minutes (1,000s). Go ahead; do the math--
r = (pi/4) * sqrt(50000 / [(1.38e-16)*3] * (300 * 300 /
Which is 489 light years.
Yes, given currently manufactured technology, the Arecibo dish could communicate with an identical dish at exactly the distance in the article, given a modest 50kW transmitter. I picked numbers to contrive the distance in question, but all of them are available with current technology, and most of them are already installed and operational at Arecibo Observatory. What if we chose a MW transmitter (available), or halved the wavelength to 10cm, or used a bigger (perhaps virtual) dish, or a lower noise antenna? All of these things would MASSIVELY improve the resolvable range of the transmission. 5000 light years is well within our current technology-limited broadcast/reception range. The hard part, as discussed by others here, is justifying implementing this much hardware and employment (versus buying ONE SINGLE JET FIGHTER).
If you think the problem with SETI lies in its technical shortcomings, you're sorely mistaken. The SETI program is a long shot for other, more difficult scientific and borderline philosophical reasons, but close examination of the physical problem at hand (which you clearly have not done) illustrates that it's not as long as your cynicism would have you judge in lieu of actual thought. You're welcome to argue your opinions, but don't mis-apply one inapt little corner of signal theory as proof that your perception of the world is, in fact, reality.
+5 Insightful? The mods have been bamboozled by unfamiliar equations. As for my analysis? Go ahead-- verify it with your favorite relevant textbook, for a change; please.
Parent
Needles in haystacks (Score:5, Funny)
But what if they communicate with... (Score:2)
All thanks to Microsoft! (Score:2)
That's Allen as in Paul Allen, you know.
SETI Institute != SETI@home != SETI (Score:4, Informative)
The SETI Institute is an organization that employs many scientists. A few of the scientists there do SETI (i.e. they search for extraterrestrial intelligence). The vast majority do not. The SETI Institute, in collaboration with the University of California Berkeley, are building a telescope called the Allen Telescope Array. Some of the scientists at the SETI Institute will use it for SETI. Other astronomers will use it for non-SETI related projects.
SETI@home is a project at the University of California Berkeley. It is neither funded by nor affiliated with the SETI Institute. In fact, some SETI scientists at the SETI Institute, dislike SETI@home because it directs attention (and therefore funding) away from SETI Institute projects. Competing projects also have some at the institute worried that someone else may be the first to detect extraterrestrial intelligence. For those reasons it is unlikely that SETI@home will ever be allowed to utilize data from the Allen Telescope Array.
From my vantage point, it appears that this confusion is promulgated by the SETI Institute. They would like the world to think that they are in control of all SETI related projects, and they would very much like to control all SETI related funding. At this point they feel that there is no advantage to preventing this confusion. In fact, scientists at the SETI Institute often drop the word "Institute" when they mention their affiliation, and just say they are "from SETI" or "with SETI".
Re:Laziness (Score:4, Informative)
I doubt there are any huge microwave beacons. If we do discover anyone out there it will only be after our arrays become powerfull enough to hear the "leakage" signals that only escape by chance, like the signals we are currently sending. But we could get lucky. It's like buying a lottery ticket.
Parent