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Earth's Radio Telescopes Combining Forces
Slatterz writes "I own a basic 70mm telescope, which I'm sure Galileo would have given his right arm for in 1609. In fact, this year marks exactly 400 years since Galileo first pointed a telescope at the skies — discovering the moons of Jupiter and helping to prove that the universe doesn't revolve around us. As a mark of respect, the United Nations has declared 2009 the International Year of Astronomy. Official festivities kick off this week in Paris and, to help start the celebrations, 17 radio telescopes in Australia, Asia, Europe and the Americas will track three quasars using something called "real-time Very Long Baseline Interferometry" — basically creating hi-res images by combining their data to simulate a telescope as large as the Earth. Sounds cool."
This is called eVLBI, and it is now done routinely to, e.g., determine the Earth's rotation (UT1).
From a networking standpoint, one interesting thing is that eVLBI requires high bandwidth (1 Gbps is typical), but can tolerate fairly high loss rates (because the actual cross correlation coefficients are rarely as high as 10^-3). This makes it an excellent candidate for an Internet scavenger service, where packets are sent at "less than best effort," i.e., with the understanding that they can be dropped if there is any congestion at all, so that eVLBI can use all available bandwidth without choking out other uses. The same technology may prove to be very useful for P2P services.
While growing up, my father imparted something of a passion for astronomy, and I remember being thrilled by a glance through his homebrew Dobsonian reflector. However, light pollution really takes any wonder out of gazing up at the heavens with a naked eye. I've been to some fairly remote places on Earth, such as central Kazakhstan and Western Sahara, but even there local authorities have put up enough lighting to seriously dim the skies. I can't imagine how glorious things must have been a century ago.
It's a pity few even realize what a problem light pollution is. If you want to really appreciate the stars, consider looking at something like Bob Mizon's Light Pollution: Responses and Remedies . But in the face of apathy from officials, there's no much hope for improvement.
The price of these telescopes is simply amazing. For a little less than $400 (I assume you have to add shipping and other stuff) you can get http://www.telescope.com/control/product/~category_id=classicdobs/~pcategory=classicdobs/~product_id=08943 that 8" dobsonian you mentioned. I only went there because of your link and the NOVA/PBS show I watched on home-built astronomy. Basically you can buy a really decent telescope for about the same price as you can build your own, so if just getting started (like I am thinking about) it is easier to buy based on recommendations of active local astronomers.
Thanks for the link. $400 is still a bit out of reach, but we'll see what tax rebate season brings.
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I have to tell a story on myself. I borrowed a 4" telescope from my college, and set out to look at various celestial wonders. Everything was fine until after looking at the moon (and having tried both eyes), I was blind! (Or so I thought). I stumbled into the house, but strangely, I could see. I went back outside, and I couldn't see anything. I finally figured out that the moon's image was bright enough to stimulate my cones and at the same time zap my rods. When I looked away outside, there wasn't enough light for the cones, so I saw nothing. Inside, there was enough light for the cones. I really scared the crap outta myself that time! Scenes from "A Christmas Story" of "You'll burn your eye out, kid" danced through my head.
Tiller's Rule: Never use a word in written form that you've only heard and never read. You will end up looking foolish.
I get a very good view of Saturn with my old 5" Newtonian. Can't make out the Cassini division, but the rings as separate from the planet are perfectly clear.
Real Daleks don't climb stairs - they level the building.
What strikes me as funny as if there was/is a God he must have a fantastically disgusting mean streak. Technically it was the Church under the Pope that like burned Gallelio right? The same Church who God supposedly told he would honor the decisions they make down here. So if the Pope condemned Gallelio to hell for telling the truth then he would be there being flayed constantly.
Of course there are other ways you can take that, but since we're talking 100% hypothetical BS I figured I'd be lazy and take the wordings at face value. Alternate beliefs and theories include bits like that "promise" being bullshit by the Church so they can keep power, or God telling lies to people down here and doing whatever He wants up there, etc etc.
Slightly less off topic though I've always wondered what past great scientists would do with modern technology. I blame Star Trek for putting the idea in my head, what with Data and his holodeck friends of Einstein, Freud, Edison and so forth. I wonder if in some cases if these "greats" are only great because they had primitive tools and were more adept at using those and would be considered mediocre if they had modern gear and knew how to use it.
After all, using an IR or Radio telescope is different than using an optical one.
You wouldn't want to upset Galileo on this date...
When I was in Florence I actually got to go see his grave. It's located in the Basilica of Santa Croce. Michelangelo's grave is also located there. They are on opposite ends of the church within sight of each other.
Rumor has it that during one of the many floods that hit Florence the remains of each came up to the surface and they had to guess at who was who when they reburied them. I don't know if this actually true or just something they tell the tourists but I paid my respects to both graves.
I want peace on earth and goodwill toward man.
We are the United States Government! We don't do that sort of thing.
Interesting.
They say:
NB: The message above might reflect my opinion right now, but not necessarily tomorrow or next year.
While the resolution of a large array can be similar to one gigantic dish, this does not mean it is as sensitive. No matter how spread the array, it is (at best) only as sensitive as the sum of its individual elements. What is nice though is that as some sites rotate out of the array, others can be brought online, which allows for continuous monitoring of a single patch of space. Even a giant array in the desert like the VLA is not capable of performing this feat since it is still just one point as far as the planet is concerned.
Mal-2
How is the Riemann zeta function like Trump rallies? Both have an endless number of trivial zeros.
Depending on where the light pollution is, the effects vary.
2. Some research suggests it messes with people's circadian rhythms (which can lead to insomnia and possible long-term health effects)
3. It can prevent numerous plants from flowering (they think it is always summer)
4. Sea turtles may migrate in the wrong direction when they hatch
5. Predator-prey relations may be skewed
6. Giant mutant spiders that eat all the insects attracted to the lights
But Englishman Thomas Harriot made the first drawing of the moon after looking through a telescope several months before Galileo, in July 1609. http://www.space.com/scienceastronomy/090114-first-moon-map.html