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New Telescope Array Goes Live For SETI
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.'"
spoken like a true liberal.
People don't "sit" on money. Even those evil evil rich people that you hate so much. They put it into a bank, and the bank loans it out to a business.
Compare this with what you would (I'm sure) prefer that the government take 100% of all money and then dole it out as the government sees fit (and we should all be thankful to the benevolent government, right?). In this case, at every step of the process of dolling out that entitlement money, some fat bureaucrat, some lazy SOB who wouldn't last 10 minutes in a private sector job, he takes his cut. And then at the end of that pipeline are the little people, the serfs, kept poor and kept dependent on government.
Yeah, that's a much better use of money than giving it to a private company.
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...
"Trolls they were, but filled with the evil will of their master: a fell race..." -- J.R.R. Tolkien on Olog-hai
Insert Fermi's paradox:
http://en.wikipedia.org/wiki/Fermi_paradox
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.
Knowledge is power. Knowledge shared is power lost.
Hardly. SETI@home is not 'SETI' - it is one small subgroup of it. If anything, it's more of a publicity stunt than serious science. As i've posted elsewhere, the processing power of SETI@home is dwarfed by a system Harvard retired in 1995, for a more powerfull system. The other problem is that the Aracebo telescope is not the best scope to be using for SETI work. It's not very steerable, it's a fixed dish in a depresion in Puerto Rico - the only aiming that can be done is by moving the receiver (the bit they fought on in GoldenEye)
If Berkley was really serious about SETI, they'd have fitted a META (MillionChannel, Extra-Terrestrial Array - http://seti.harvard.edu/seti/meta.html) or a BETA (BillionChannel Extra-Terrestrial Array - http://seti.harvard.edu/seti/setihist.html) to process it. It actually takes about as much hardware for a META as is needed for the backend of the BOINC client.
If you really want to help space exploration, and science, and communication, you'd be better off with a project like the Muon1 DPAD (http://stephenbrooks.org/muon1/ ), working on the Neutreno, which may be a viable communicative method when understood, as it appears to not generally interact with matter. imagine Europe-Japan communication direct, beamed through the earth, rather than via satelites, or cables run on the surface/ocean floor.
http://www.torrentfreak.com
http://neuron2neuron.blogspot.com
http://www.piracyisnotacrime.com
"I think SETI is a hopeless pipe dream."
.211m. The brightness temperature of the galaxy as viewed from Earth's surface is around 5-10 Kelvin at that wavelength.
.211) = 4.63*10^18 meters
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.
No no no, That equation does not work in a vacuum. The air loss needs something else...namely....air ;)
How is it that we can pick up the little tiny signal coming from voyager which went so far beyond us is your equation worked in a vacuum? I guess we would not.