A Telescope as Big as the Earth 172
Roland Piquepaille writes "A week ago, seven telescopes around the world were linked together to watch a distant galaxy called 3C273 in real time and create a single world telescope. The data from these telescopes, which are located in Australia, China and Europe, was streamed around the world at a rate of 256 Mb per second. One of the Australian researchers involved in the project said that it was the first time that astronomers have been able to instantaneously connect telescopes half a world apart. He added that 'the diameter of the Earth is 12,750 km and the two most widely separated telescopes in our experiment were 12,304 km apart.'"
Unfortunately... (Score:5, Funny)
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FYI (Score:5, Informative)
Re:FYI (Score:5, Funny)
Re:FYI (Score:5, Informative)
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(I work up the hill from the westernmost VLBA dish.)
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See http://www.jive.nl/ [www.jive.nl] for all the details and http://www.astron.nl/dailyimage/main.php?date=2007 0906 [astron.nl] for some images.
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One advantage of the actual earth-sized telescope is that if you tweak the electronics a bit, then the instrument can also be used as a weapon to destroy rebellious planets.
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Re:FYI (Score:5, Informative)
Resolution(radians) = Wavelength/Diameter
When you do this kind of technique, you increase the angular resolution that can be picked up to that of a full telescope over the area (if designed properly to get the middle resolutions as well). However, as others have mentioned, you don't get the full number of photons, which means you have to increase the imaging time or allow for much high SNRs. However, this is still very useful for getting high resolution images of fairly bright objects.
Re:FYI (Score:4, Informative)
For example, the Very Large Array has 27 antennae. That's 351 pairs, which can be spaced differently. If you had a single dish telescope the size of the VLA (or the Earth), you'd get every angular scale at once, without having to synthesize a large aperture from all the baselines.
In practice, this aperture synthesis [wikipedia.org] technique works quite well, and there's no way we're going to build a steerable single dish telescope larger than the Green Bank Telescope [wikipedia.org] (100m in diameter) any time in the foreseeable future.
Central Obstruction (Score:5, Funny)
Ok. That might be the geekiest joke in the histroy of
:(
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Re:Central Obstruction (Score:4, Informative)
http://en.wikipedia.org/wiki/Schmidt-Cassegrain_t
They have a large central obstruction which houses the secondary mirror.
Central Obstrcutions come with negative affects.
http://www.telescope-optics.net/obstruction.htm
So I was making a very bad and geeky joke based on the headline about this being a very large telescope with the entire Earth as its central obsutrction. Which, in a *very* round-about sense, it is.
Were they looking in the optical range? (Score:1, Interesting)
Re:Were they looking in the optical range? (Score:5, Informative)
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Damn. This means all we got for this was reruns of the Aploterix! and Andy show from Betelgeuse.
Re:Were they looking in the optical range? (Score:4, Informative)
However, expanding it to optical frequencies (where you can pick up different types of objects and also do so to much higher resolution) is difficult, since the wavelengths are around 500 nanometers, a level of precision that is still impossible on worldwide scales, except maybe in space, where you can depend on laser range finding over very long distances, although i don't know of any proposals trying to do this over very large scale.
need both amplitude and phase to enlarge aperture (Score:2)
Before signal processing was fast enough they cross-correlated the analog radio signals. This is how VBLI astronomy works.
The do this with opti
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You may be thinking of an interferometer. It's virtually the same thing. Very Large Baseline Inteferometry (VLBI)has been around a long time. The deal here is that now it can be done in real time.
Cool (Score:3, Interesting)
Re:Cool (Score:5, Informative)
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And now there's Stellarium [stellarium.org] available for free to do this.
All at once (Score:5, Funny)
Re:All at once: you missed the new one (Score:2)
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Real time? (Score:3, Insightful)
> single world telescope.
Not to be overly pedantic, but the data were streamed from all over the world to a location in Europe, then processed, and then streamed to China for viewing.
Even though they weren't going over the public net, that's still almost certainly >1000ms latency. Harldy "real time".
Although, I suppose that's acceptable on top of the two and a half years it took for the photons to get to us.
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I just wiki'd 3C 273 [wikipedia.org] and took the distance from that, but I see now that's a quasar, not a galaxy.
Perhaps TFA made a mistake? It seems unlikely that there would be both a galaxy and a quasar with that name.
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A quaser that close to the earth would be a less than pleasant galactic neighbor.
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Hrm.
I just wiki'd 3C 273 [wikipedia.org] and took the distance from that, but I see now that's a quasar, not a igalaxy.
Perhaps TFA made a mistake? It seems unlikely that there would be both a galaxy and a quasar with that name.
Quasars [wikipedia.org] are at the center of galaxies. There are a few possibilities for what is actually happening; most likely the scientists are studying the quasar, mentioned it was the center of a galaxy, and the nontechnical reporter made a small mistake.
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damn my unscientific mind
Wrong it is not 4.22 years. (Score:5, Funny)
Re:Wrong it is not 4.22 years. (Score:4, Insightful)
Re:Wrong it is not 4.22 years. (Score:5, Funny)
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time from photon's POV = time_from_our_view * sqrt( 1- v^2 / c^2)
Putting in v=c:
time from photon's POV = time_from_our_view * sqrt( 1- 1) = 0 seconds
There you go.
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50 million years (source: Lewis, Richard (1983). The Illustrated Encyclopedia of the Universe. Harmony Books, New York, 65.)
or 17,000 years (source: Plait, Phil (1997). Bitesize Tour of the Solar System: The Long Climb from the Sun's Core. Bad Astronomy. Retrieved on 2006-03-22.)
(or somewhere between)
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OK (Score:2, Insightful)
This stunt is a technical accomplishment but maybe not that important in and of itself. What would get me excited would be a couple of orbiting 'scopes.
Re:OK (Score:5, Informative)
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Now imaging... (Score:1)
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Why bother landing telescopes on other worlds? (Score:2)
As a bonus, these telescopes would also increase, year by year, the range of the parallax technique, the most accurate technique for finding stellar dist
Lightspeed Broken! (Score:5, Funny)
This is the real story - FTL communications!
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See http://www.jive.nl/ [www.jive.nl] [www.jive.nl] for all the details and http://www.astron.nl/dailyimage/main.php?date=200
A source of hope (Score:5, Insightful)
Wow, that's depressing (Score:3, Funny)
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If it makes you feel any better, it's really closer to 50%, and most of those people were douchebags.
How many people have ever lived? (Score:2)
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The Singularity is nearing.
What About C? (Score:1)
(get off my porch)
VLBI has been doing this since the late 1960's (Score:2)
What is new here is the real time data transport, not the observations.
This seems impressive but... (Score:1, Funny)
Curiousity Question (Score:2, Interesting)
So, when measuring the distance between each of the telescopes, did he do it through the planet (diameter), or did he measure the distance across the surface of the planet (circumference)? Cause that kind makes a huge difference, and really screws up any valid comparison between the two distances.
~Sticky
/You know, kind of like comparing English furlongs and Austr
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Did they see anything? (Score:2)
Apologies to Steven Wright... (Score:2)
It's the Internet, stupid! (Score:2)
Galaxy or Quasar? (Score:2)
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"Quasar" is short for "Quasi-stellar object" which is what they were called when they were first discovered. At the time, they were unresolved sources a bit like, but clearly not, stars. Since then it has been discovered that quasars are one form of active galaxy, where accretion onto the black hole in the nucleus of the galaxy releases a lot of energy. So in this sense "galaxy" is accurate. If someone wants to specifically talk about the rest of the gal
USA was left out... (Score:2, Funny)
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A major part of this effort has been getting the Gbit/s quality links to the telescopes, that are often in a desert in the middle of nowhere, as you want to avoid radio-interference from human sources, so you prefer places that have no human inhabitants within 200-300 km of your location.
Why bother being instantaneous? (Score:3, Interesting)
Its not like it was a live event where you had to have it just then.
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Data rate (Score:3, Informative)
This means that over 10 seconds 2560Mb of data would be streamed, according to NASA.
Where are the pics? (Score:2)
Why realtime ? (Score:2)
I've been waiting for this VLBI (Score:2)
On a line (Score:2)
Heh (Score:5, Funny)
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Really? (Score:3, Interesting)
Re:Really? (Score:5, Funny)
Re:Really? (Score:5, Funny)
Before 1923? No spoiler warning needed. (Score:2)
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How about:
http://www.lofar.org/ [lofar.org]
http://www.astron.nl/p/lofarframe.htm [astron.nl]
No, it runs Windows ME. (Score:5, Funny)
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So at this point, possible but expensive. I could see it as a 50-year-out kind of technology, unless someone decides it r
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