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As extremely broad-band radio astronomy receivers (think GHz rather than tens of MHz) are on the way (e.g. the plans for the EVLA) radio astronomers are going to have to abandon the idea of completely RFI-free bands (already a myth at 1.4 GHz and below) and concentrate on ways of automatically detecting and removing it instead. Of course, large numbers of small, frequency-agile transmitters are pretty much the worst nightmare in this sort of scenario...

the technique is several decades old and the article is essentially contentless.

array of radio telescopes scattered around the whole earch can act like a single telescope if we combine the signal coherently. this can be done by connecting them together in real time (e.g. VLA in New Mexico) or offline (e.g. VLBA). Both VLA and VLBA are run by NRAO. if you want to do offline, you need to preserve amplitude, phase and timing information. atomic clocks are used for time stamping and supercomputers are used to combine signal. this simulates a large telescope whose lens is mostly opaque, save for few dots! the technique is really old (originated in late 60s, early 70s) and has been well mastered for more than 20 years. so there is absolutely nothing new in the article. depending upon the scientific relevance, many global telescopes participate in these experiments. in some cases, only US telescopes (VLBA which is scattered from hawaii to virgin islands) participate, which creates somewhat smaller effective telescope size. some experiments have beed done using space based radio telescopes which increases effective size even further (by the time, the space telescope became operational in late 90s, i left astronomy, so don't know the results).

the supercomputer which combines signal is made up of custom chips and uses custom OS. linux part is quite small and it comes into picture well after the data has been pre-processed (raw data sizes could be few terrabytes a day while processed data is only few gigabytes).

Let's see what that may include:

• UK: "Although it is not illegal to sell, buy or own a scanning or other receiver in the UK, it must only be used to listen to transmissions meant for GENERAL RECEPTION. The services that you can listen to include Amateur and Citizens' Band transmissions, licensed broadcast radio and weather and navigation broadcasts."
• West Virginia: " It shall be illegal to operate or cause to be operated any electrical equipment within a two-mile radius of the reception equipment of any radio astronomy facility if such operation causes interference with reception by said radio astronomy facility of radio waves emanating from any nonterrestrial source." So you need a GPS receiver and a network link...or a postcard... to the radio astronomy facility so as to check if you're interfering?
• Canada, France, Germany, Greece, Greenland, Israel, Italy, Luxembourg, Malta, New Caledonia, North Africa, Norway, Portugal, Singapore, South Korea, Spain, Thailand, Turkey,USA: Scanners illegal or reception of non-public signals forbidden.
• USA: Mobile scanners restricted in many states.
• USA: "unlawful to disclose the content of radio transmissions overheard unless they are amateur radio traffic, broadcasts to the public or distress calls."

"But it frustrates me that so many scientists always seem to believe that water in a liquid form is a necessity of life."

Scientists do not have to believe anything that was not proven yet. Put out a theory that can be tested and maybe then you'll have the right to get frustrated with people who always require some kind of evidence to exist before they start believing in things that they have not seen or proven theoretically.

Water is the best solvent known to our kind that stays liquid between degrees 0C and 100C at ground atmospheric pressure and protected by layer of ozone from various types of radiation from being broken down into oxygen and hydrogen by high energy elements.

There are other types of chemicals that can become solvents: Ammonia, for example melts at negative 77C and boils at negative 33.5C So it is not impossible to use ammonia as a solvent at lower temperatures to do the same things water does at our temperatures. However, notice that with ammonia as a solvent, the actual energy in the system is much lower than in the system at higher temperatures. Thus the chemical reactions will happen much slower if ammonia is used as a solvent at lower temperatures. On the other hand, at higher temperatures some forms of liquid metal can be used as solvents, the problem with those is that at such temperatures things burn. Of-course here comes silicon. Silicon is known to be almost as good at creating long chains as carbon, but not exactly as good. In nature long carbon chains are much more prevalent than long silicon chains, in space we find alcohol molecules - a mix of hydrogen, oxygen and carbon atoms. B.T.W. Carbon is a much more common element in the universe than silicon:

4 1H --> 4He.

3 4He --> 12C.

12C + 4He --> 16O.

12C + 12C --> 24Mg.

etc. making 28Si, 32S, ...

This is the life of main sequence star, where every next stage is less possible and is much shorter than the previous one and every next stage requires more energy (pressure-temperature) to continue the thermonuclear reactions going. Carbon in these reactions are found much earlier than silicon thus there is more carbon in the universe than there is silicon.

Anyway, my point is that there is no reason to get frustrated with scientists. The science will explain everything to us in due time.

Cheers.

On a related note, I was just reading a page at the VLBA, and their data collection methods sound rather archaic:

Astronomical data from the observations are recorded on digital tape at each antenna site. The tapes are then shipped to the Socorro Operations Center where they are correlated and the results sent to the scientists.

I just recently finished a summer internship at the National Radio Astronomy Observatory (which is the organization behind creating and running the VLA) and there is a new project going on there to build a huge interferometer in Chile. I just thought I'd make mention of it for all you astronomy buffs out there. Check it out at http://www.alma.nrao.edu/

" If they succeed the SKA will be so big and precise it will jump the world's current best, the American Very Large Array in New Mexico, by a factor of 100, both in sensitivity and resolution."

Fortunately it's only compared to the VLA in regards of resolution. Single radiotelescopes have no chance in hell to get to extreme resolutions. Resolution is all in the diameter, or baseline. Nothing you can do about, it's just basic physics. Fortunately you can have big holes in your telescope, or inversely just a few parts of the surface. Excactly the principle of the VLA and VLBI in radio frequencies and the VLTI for light. You can even find a simulation applet here

In fact the earth itself is getting too small to get more resolution. Going into space is indeed being looked into, but not in the sense of a satellite like the Hubble orbiting the earth. That would hardly be worth the effort where radio astronomy is concerned. Having a baseline as long as the distance between the earth and the moon, now that would be an improvement. Plus, if it's built on the side that's always turned away from the earth, the telescope will be shielded from all the annoying interference created by all the radiochatter on earth, while it's still possible to look at the same piece of sky as an earth based telescope.

In the visual spectrum, Darwin from ESA looks set to become the next record holder . A first technology demonstration/development flight in the form of SMART-2 is currently under development.

As an example, AIPS, a program many radio astronomers are intimately familiar with, was written ~1980 for reduction of interferometer data. It has been continually supported and maintained since then, and there appears to be no planned end to its use.

I looked into doing exactly this about seven years ago and the prospects were dismal.

Building such a phased array is certainly possible, but the grief you'd have to go through to get it to work would be tremendous.

1. The total area of the smaller dishes would have to be at least the area of the big dish you're replacing, i.e. you'd need at least 45 18" dishes to equal the area of a single 10' dish.

2. You will need to steer your array of small dishes together to point at the desired satellite. The pointing accuracy of each would have to be on the order of a couple of degrees.

3. You'd need a phasing network to add the signals from each of those dishes together with the correct phasing. Note that the phasing will change as you steer the dish system. The network would have to have sufficient bandwidth to cover the spectrum of interest, which is not going to be easy. The design of such a monster would probably get you a PhD and a very good job at a major corporation.

4. The low noise amplifiers used (one per dish) would have to be very low noise indeed, since their contribution to the total noise of the phased signal goes as the square root of their number. If you've got 45 small dishes, each LNA would have to be only about 1/7 as noisy as would the amplifier for the single dish system.

I could go on, but realize what a horrible mess this would be. Arrays of dish antennas are used by radioastronomers for various reasons. The Very Large Array in New Mexico uses 27 25-meter telescopes to obtain very high angular resolution images. All of those antennas combine to become the equivalent of one 130-meter antenna.

A project of interest to those reading this is the Allen Telescope Array being built by the SETI Institute. It will use 350 6-meter TVRO dishes phased together to create one large radiotelescope. The engineering issues involved are extremely complicated.

Bottom line: it would be easier and cheaper to bribe your community's zoning board to give you a variance for a big dish, than it would be to build a phased array of smaller dishes. Even if you got prosecuted, the jail time would probably end up being less than the design time.

The Very Large Array, one of the world's premier astronomical radio observatories, consists of 27 radio antennas in a Y-shaped configuration on the Plains of San Agustin fifty miles west of Socorro, New Mexico. Each antenna is 25 meters (81 feet) in diameter. The data from the antennas is combined electronically to give the resolution of an antenna 36km (22 miles) across, with the sensitivity of a dish 130 meters (422 feet) in diameter.

What you want to do is called Aperture Synthesis (or Inferometry) - It's what the VLA uses to combine the signals from it's 27 25m dishes to work like a single 130m dish.

There is some information on theory here, but I think building a device to actually do what you want will be very hard. Good Luck!

As far as tracking goes, the Green Bank radio telescope (see also my post farther down) uses adaptive computer control of the telescope surface, including laser ranging to each of the surface panels coupled to actuators that can restore the surface's shape in the face of wind, gravity, or other problems (tip a telescope that big down to 5 degrees from the horizon and you definitely will see gravity pulling it out of shape). Eventually this control will be "closed-loop"; the system will automatically detect deformation of the telescope surface and restore the proper shape.

It seems like this might be a reasonable approach to keeping large optical telescopes in shape; just put actuators at the mirror corners and use the same laser ranging method. You might have to tighten up the measurement tolerances since a fraction of a radio wave is much larger than a fraction of a light wave, but the GBT is 1990 or earlier technology so I imagine we can do a lot better today.

Although really I don't see much point in building such a large optical telescope on the Earth's surface anyway; most of the deformation issues with compound elements should be a lot easier to deal with in space, the Earth's atmosphere is, if anything, getting worse at the moment, you have to care about the weather, etc.

You can integrate the images from lots of smaller mirrors pretty easily in software

Actually, that's hideously hard. Despite the suggestion made (by both the people running the VLT along with the /. post), I don't know that anyone has actually used either Keck or the VLT in multi-telescope mode for "real science". It turns out that optical interferometry is much harder than radio interferometry (see the VLA) and no one has successfully done it in any sort of regular way yet (I believe that they've done it once on Keck and once using two of the VLA telescopes, but never using all four).

In short, people are discovering that doing optical interferometry is REALLY hard and building one, large telescope saves a lot of headaches (but, of course, is a lot more expensive).

Finally, having a telescope in space really does help out a lot for getting better resolution, but there is something to be said for large telescopes on the ground. They are able to gather more light and, hence, able to get a higher signal-to-noise ratio than a smaller, space-based telescope.

Exactly - these optical folks with their "overwhelming" and "stupendous" telescopes are really small fry.

For example, the Green Bank Telescope is the world's largest fully steerable telescope, with an oblong surface measuring 100 by 110 meters and a surface area of 8000 square meters. It is taller than the Statue of Liberty. It looms over the West Virginia countryside like something out of Star Wars.

"Overwhelmingly Large" my ass!

Exactly - these optical folks with their "overwhelming" and "stupendous" telescopes are really small fry.

For example, the Green Bank Telescope is the world's largest fully steerable telescope, with an oblong surface measuring 100 by 110 meters and a surface area of 8000 square meters. It is taller than the Statue of Liberty. It looms over the West Virginia countryside like something out of Star Wars.

"Overwhelmingly Large" my ass!

Actually, Fortran still is quite popular in the field of scientific computing. Fortran90/95 and High Performance Fortran that is, definitely NOT Fortran77.

Actually, Fortran77 is still common in astronomy, partly (or mostly?) due to inertia. A lot of code is written in old Fortran, such as the NRAO Astronomical Image Processing System (AIPS).

During my degree we were taught Fortran90, but during my Ph.D. so much of the old code was Fortran77, and so many of the people you'd work with still used it, that many people ended up writing Fortran77 anyway. Of course, I'm not saying that's a good thing, that's just how it was :-)

It's starting to change, though... the new AIPS++ is written in C++, and I haven't written any Fortran for ages.

Actually, Fortran still is quite popular in the field of scientific computing. Fortran90/95 and High Performance Fortran that is, definitely NOT Fortran77.

Actually, Fortran77 is still common in astronomy, partly (or mostly?) due to inertia. A lot of code is written in old Fortran, such as the NRAO Astronomical Image Processing System (AIPS).

During my degree we were taught Fortran90, but during my Ph.D. so much of the old code was Fortran77, and so many of the people you'd work with still used it, that many people ended up writing Fortran77 anyway. Of course, I'm not saying that's a good thing, that's just how it was :-)

It's starting to change, though... the new AIPS++ is written in C++, and I haven't written any Fortran for ages.

Actually, Fortran still is quite popular in the field of scientific computing. Fortran90/95 and High Performance Fortran that is, definitely NOT Fortran77.

Actually, Fortran77 is still common in astronomy, partly (or mostly?) due to inertia. A lot of code is written in old Fortran, such as the NRAO Astronomical Image Processing System (AIPS).

During my degree we were taught Fortran90, but during my Ph.D. so much of the old code was Fortran77, and so many of the people you'd work with still used it, that many people ended up writing Fortran77 anyway. Of course, I'm not saying that's a good thing, that's just how it was :-)

It's starting to change, though... the new AIPS++ is written in C++, and I haven't written any Fortran for ages.

The article doesn't say how the nebula was observed, but it's entirely possible it was not using visible light at all but IR, UV, XRAY, whatever (I'm no astronomy expert, but I know they don't always limit themselves to the visible spectrum).

You're right. It actually mentions that the work was done with the Very Long Baseline Array (VLBA) which is a radio telescope.

Linking several together gives you a theoretical mirror many hundereds of miles wide.

Whilst you can do this at radio wavelengths, and have baselines (the separation between individual telescopes) the size of continents as with the VLBA, it is more difficult at optical wavelengths. This is essentially because the much shorter wavelengths make for much tighter tolerances in combining the signals. As far as I know, the current state of the art gives separations of only about 100 metres, rather than miles. See for example COAST and Optical Long Baseline Interferometry News.

In my NSH opinion, RTF and DOC formats are one and the same; the former is just an ascii markup version of the latter. Both should be avoided like the plague.

Read my rant^H^H^H^HTreatise on the topic of document interchange for more info.

>> First the possible. A quick, back of a napkin
>> calculation shows that a supernovae at around 3
>> light years would appear roughly as bright as the
>> sun (depending on the circumstances).

You also forgot about what would happen 10-100 years later, when the actual blast wave of debris reached us.

Betelgeuse, which is around 500 LY away, may make travel in our solar system impossible (or a lot more costly) for a hundred years.

The ionized interstellar medium causes a dispersion ofthe pulses, such that pulses emitted at low radio frequencies arrive later than those emitted at higher frequencies

Home of the National Radio Astronomy Observatory.
NRAO

Of course, he probably wouldn't believe those huge antennas were actually receivers.

At least he'd be close to skiing.

Yes, that's the National Radio Quiet Zone, which covers 13,000 square miles of West Virginia. It was created to create a quiet enough area that spying on RF emissions from the USSR via moonbounce would work. It's retained for radio astronomy.

You're referring to Greenbank, West Virginia, which is part of the NRAO. You can get info about it here. It's pretty cool. I've been there 3 times as part of an astronomy group when I was in college.

The world's largest steerable radio telescope measures only 110 x 100 meters.

And, it can be used during the daytime. The optical wavelengths given off by the sun don't interfere with radio astronomy. The sun does give off RF interference, but you have to point the telescope almost directly at the sun to encounter a problem.

You wouldn't have to launch billions of tons from Earth. Techniques for processing lunar materials into structural building components have been tested for decades.

Xephem (a planetarium and analysis program for linux) is very cool because it can both pull the sky from your LX200 telescope or by replacing the telescope driver with a perl script, it can download part of the sky from an online database, after which you can do realtime image processing on it.

It can also match stars in the sky to stars in the database. So far I have only been able to pull down large segments of the sky at once, but as soon as I can clear the disk space I'll be trying some other pieces of software to try and download smaller pieces of the sky. Starry Night also downloads DSS (Digital Sky Survey) images I believe.

NASA Skyview service
Multimission Archive
StarView
Software for different platforms (or check freshmeat.net)
Serious scientific platforms/data
Skyview (available at IPAC) is available as linux binary and installs quickly at 10mb. It lets you do image analysis with text commands. I have not used it a lot myself.
AstroWeb

This was observed using the National Radio Astronomy Observatory's Very Large Array, which is a (rather cool looking) group of 27 radio antennas in New Mexico. The NRAO press release on K3-35 contains somewhat more detailed information than the CNN article.

This was observed using the National Radio Astronomy Observatory's Very Large Array, which is a (rather cool looking) group of 27 radio antennas in New Mexico. The NRAO press release on K3-35 contains somewhat more detailed information than the CNN article.

This was observed using the National Radio Astronomy Observatory's Very Large Array, which is a (rather cool looking) group of 27 radio antennas in New Mexico. The NRAO press release on K3-35 contains somewhat more detailed information than the CNN article.

FWIW, I actually use OpenWindows as my desktop (oh, the horror, the horror!) and along with olvwm, it does its job and stays out of the way. All my real work is done with xterms, gcc/cc, emacs (so go on, flame me) and custom astronomy software. If you ever had the misfortune to use AIPS, you'd be into B&D too.

With Linux (and gnome) on my laptop and on our newer production machines, I just don't know: it looks (and feels) clunky. What 5 year old drew those ugly icons? Even with the "tiny icons" on my laptop Gnome toolbar, the only icon I actually like is the simple red star of Mozilla. And my work is all at the command line, I don't use icons! But I still can't convince Gnome, even with repeated "Save settings," that I'd rather not have an icons for /dev/fd0 and /dev/hda cluttering my desktop. Non-intuitive, hard to learn (this from an OpenWindows user!!) and ugly: is there any reason for Sun to switch to Gnome besides saving development costs?

I, for one, am not impressed.

For one thing, they broadcast at 1.6 and 2.5 GHz, smack in the most interesting radio astronomy bands. 1.6 GHz in particular is the frequency at which we see hydroxyl (-OH) radicals, and if you can't see why that is interesting, you need a drink. Fine, so we have global and large scale arrays which have antennas seperated by many miles - but to an array, a satellite is a real astronomical signal, and it is very very hard to filter it out (as opposed to a motorcycle spark plug or even cellphones, which do not produce correlated interference at many antennas).

And what makes it worse is that these companies wilfully violate international treaties which protect precious scraps of the spectrum for astronomy - "We're big companies and we make real money, get out of the way" - and really can't believe that their low low sidebands are stronger than our astronomical signals by factors of 1000s.

Ah well, there's progress for you - astronomy is sacrificed so that you can download pr0n in the middle of the Sahara. And we nearly had the last laugh, too.

Yes, but it would be unbelieveably difficult. Ground telescopes that use so called aperture synthesis can achieve resolutions which approximate the resolution you would expect if you had one huge telescope the size of the separation distance or "baseline" of the two smaller separated telescopes(the basic idea of astronomical interferometery), but there is a (BIG)catch. In order to 'get fringes' or achieve interferometry, you must combine the light from the array of telescopes with the same high tolerances that you would need to use with one giant telescope the size of the baseline. That means the mirrors and beam splitters/combiners of the entire system must be held to within 1/10th of a fraction of the wavelength of light that you are observing with. If you assume yellow light with a wavelength of 5X10^-7 meters you would have to know the positions of the optics in the system to within 50 Nanometers or billionths of a meter. This is possible on earth and is even being done on large scales such as at Keck and the ESO's VLT. If you can figure out a way for two telescopes orbiting the earth 200Km up(and varying in altitude by METERS everyday because of drag with the upper atmosphere) to know their position with respecto to eachother to within a tiny fraction of the diameter of a hair, let me know; the King of Sweden wants to see you. (BTW this trick is not so hard at centemeter wavelenghts; the baseline of this system stretches from Hawaii to New Hampshire and the resolution in this VLBA image is nearly 1000 times higher than the hubble space telescope can achieve.)

Yes, but it would be unbelieveably difficult. Ground telescopes that use so called aperture synthesis can achieve resolutions which approximate the resolution you would expect if you had one huge telescope the size of the separation distance or "baseline" of the two smaller separated telescopes(the basic idea of astronomical interferometery), but there is a (BIG)catch. In order to 'get fringes' or achieve interferometry, you must combine the light from the array of telescopes with the same high tolerances that you would need to use with one giant telescope the size of the baseline. That means the mirrors and beam splitters/combiners of the entire system must be held to within 1/10th of a fraction of the wavelength of light that you are observing with. If you assume yellow light with a wavelength of 5X10^-7 meters you would have to know the positions of the optics in the system to within 50 Nanometers or billionths of a meter. This is possible on earth and is even being done on large scales such as at Keck and the ESO's VLT. If you can figure out a way for two telescopes orbiting the earth 200Km up(and varying in altitude by METERS everyday because of drag with the upper atmosphere) to know their position with respecto to eachother to within a tiny fraction of the diameter of a hair, let me know; the King of Sweden wants to see you. (BTW this trick is not so hard at centemeter wavelenghts; the baseline of this system stretches from Hawaii to New Hampshire and the resolution in this VLBA image is nearly 1000 times higher than the hubble space telescope can achieve.)

Yes, but it would be unbelieveably difficult. Ground telescopes that use so called aperture synthesis can achieve resolutions which approximate the resolution you would expect if you had one huge telescope the size of the separation distance or "baseline" of the two smaller separated telescopes(the basic idea of astronomical interferometery), but there is a (BIG)catch. In order to 'get fringes' or achieve interferometry, you must combine the light from the array of telescopes with the same high tolerances that you would need to use with one giant telescope the size of the baseline. That means the mirrors and beam splitters/combiners of the entire system must be held to within 1/10th of a fraction of the wavelength of light that you are observing with. If you assume yellow light with a wavelength of 5X10^-7 meters you would have to know the positions of the optics in the system to within 50 Nanometers or billionths of a meter. This is possible on earth and is even being done on large scales such as at Keck and the ESO's VLT. If you can figure out a way for two telescopes orbiting the earth 200Km up(and varying in altitude by METERS everyday because of drag with the upper atmosphere) to know their position with respecto to eachother to within a tiny fraction of the diameter of a hair, let me know; the King of Sweden wants to see you. (BTW this trick is not so hard at centemeter wavelenghts; the baseline of this system stretches from Hawaii to New Hampshire and the resolution in this VLBA image is nearly 1000 times higher than the hubble space telescope can achieve.)

It's very cool place to visit, BTW. I would say something like "visit it if you're in the area", but it's the ONLY thing the area - if you're actually in the area, chances are you're already going there. :-)

--

There are astronomical institutions which are not degree-granting, but are in the .edu domain.

Gemini will not be an interferometer. For interferometry, you have to know the distance between the telescopes to an accuracy smaller than the wavelength used. Another thing is that you should either combine the beams from both telescopes, or get the phase information of each photon. In radio, it is possible to get the phase information. In optical, Keck and VLT can combine the beams. For Gemini, this would need quite a lot of optical fiber ;) The main goal of Gemini is to have identical state-of-the-art systems for observing both northern and southern sky.

IMHO X-ray astronomy is much more interesting, but I fear it will take some time before we get the X-ray interferometer, but I have heard some rumours on it.

Another cool site devoted to Bose: http://www.tuc.nrao.edu/~demerson/bose/bose.html

I hate to nitpick, but Arecibo is not a volcanic caldera, in spite of what the tabloid press might report. In fact, it is a large limestone sinkhole in the karst terrain of Puerto Rico: check out this link for more info. (I promise its not a goatse.cx link.)

One of the cuter stories is that when they were searching for the perfect site on Puerto Rico, they took a dime and slid it around on a contour map of the island - and where it fit nicely inside the contours, there the dish went... Its amazing to look at, and I recommend a visit if you vacation in PR.

OTOH, your other point is completely correct - Arecibo only sees a limited range of the sky, and cannot view anything south of a certain declination (14? I forget). Not being able to see the Gal;actic center is particularly galling! That's why the new GBT (100m, unlike 305m at Arecibo, but the GBT is fully steerable) is so exciting.

As an astrophysics major I'd like to reiterate that radio telescopes are an incredibly useful tool for astronomers and are not a product of SETI. The merits of SETI aside, projects like the Very Large Array (VLA) and this are a tremedous boon to the field of astronomy. Of particular interest are studies of objects such as QUASARs and Active Galactic Nuclei, many of which are radio sources, and both of which are poorly understood. (An aside, even though QUASAR came from quasi-stellar radio source they are not all radio sources.) For more information on the non-SETI uses of radio astronomy I direct you to NRAO at http://www.gb.nrao.edu/ and the FIRST survey at http://sundog.stsci.edu/ . These sites are of course only a sample and are the first ones that came to my mind. Antiam

When I was an undergrad (I'm an astrophysics grad student now), I spent 1 1/2 years doing research for a radio astronomer who was a member of the International Astronomical Union (as most astronomers are). A significant part of his time was spent lobbying for the SKA, and I got the opportunity to learn a lot about the device.

The main thrust of the Square Kilometer Array is NOT to detect extraterrestrial life. That happens to be one of the flashier goals, but it isn't the most interesting to most astronomers. Since more collecting area=more sensitivity and larger baseline = more resolution for a telescope, the SKA will be the most sensitive telescope ever built, though not necessarily capable of the highest resolution (the USA's Very Large Baseline Interferometer currently holds that record). Some of the many topics of interest that will be examined with the SKA include the large scale structure of the universe, first galaxy formation, the intergalactic medium, figuring out what powers quasars and radio galaxies, pulsars, and the radio properties of main-sequence stars. And, of course, looking for other technological civilizations.

It takes a long time to build huge telescopes, not because they are incredibly complex (which they are) or because they are incredibly expensive (they are, but not prohibitively so) but because governments are the ones funding them, and also because astronomers need to make compromises to that the telescope can serve the most users possible as well and as efficiently as possible. Fifteen years is a long time, but the telescope won't be out of date when it is constructed! Most of that 15 years will be spent lobbying for funds, finding a suitable location, getting the necessary permits, doing feasability studies, developing technology (coordinating radio interferometry between 2 dishes is difficult - thousands even more so!), etc. etc. And THEN it gets built, near the end of that 15 years. And, like the Hubble Space Telescope, the Very Large Array, the Very Long Baseline Array and the Chandresekhar X-Ray Observatory (all of which took 15-20+ years to lobby, fund, design and build), the SKA will once again radically change the way we look at the sky.

Here are a few links for interested parties:
Homepage of the Square Kilometer Array
Nat'l Radio Astronomy Observatories The home of the VLA, VLBI and Arecibo
International Astronomical Union Homepage

If you could get a few dozen of these out in a nice open field, and track them all the same (need a decent multi-axis rotator device) wouldn't this parallel array perform like a single large dish? (Same principle the VLA uses to make a bunch of big dishes work like one really massive dish). You could perform radio astronomy or SETI projects yourself at home. Probably need to upgrade the feedhorn/LNBA to something capable of tuning frequencies other than sat TV.

There are some cool pictures of the 300ft one that collapsed here

There is a National Radio Quiet Zone that protects the National Radio Astronomy Observatory at Green Bank and the NSA intercept station at Sugar Grove.

Sean

Light is just a part of the electromagnetic spectrum that runs all the way from radio waves (very low frequency and long wave lengths) to stuff like gamma rays (high frequency and short wavelengths). All of these are 'light' in a sense and carry useful astronomical data.

For example, many galaxies (known as radio galaxies) emit strongly in these low frequency bands and a telescope such as this allows them to be observed so we might get some clue as to what's going on.

Radio telescopes must be huge to achieve a decent resolution, which goes as (wavelength)/(size of aperature). In this case wavelength is on the order of centimeters to meters and aperature is on the order of 100 meters.

Also, the Very Large Array, as seen in the adaptation of Carl Sagen's Contact is a radio telescope.

See NRAO for some examples of what radio astronomy is all about.

Why don't you actually read the link in the story? It explains it perfectly well.