NeoCode writes: "It's been 11 years already and the stats are mind boggling. Hubble is celebrating its 11th birthday and it sent another beautiful image. Stories here (CNN) and here (Space). A lot of these images have been called "space-art". The image bank can be found here."
Re:The largest waste of my money
by
RayChuang
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· Score: 3
If I could moderate I'd mod you down to troll status.:-)
The thing about Hubble--epecially since COSTAR was installed--is that it offers extremely sharp pictures you'll never see on a ground-based telescope, even with the new telescopes going up at Mauna Kea in Hawaii and the European Southern Observatory in Chile.
The reason is simple: no atmospheric interference. Even at the high altitudes of the ground observatories I mentioned, you still have a lot of atmosphere to contend with.
Why do you think both NASA and ESA are on a fairly fast track to build more powerful space telescopes that will be launched starting late this decade?
Actually, the real image bank can be found here. It's got a lot of image series neatly lined up. The link in the story only shows the last (Horsehead Nebula) series.
"Hubble was launched by the shuttle Discovery on April 24, 1990. Two days later, the telescope was on its own, drifting into space, recording cosmic images."
"On its own, drifting into space, the Hubble space telescope is a reckless, lone rebel without a cause."
Higher quality, higher res pics available
by
Joe+Hardy+(_yoda)
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· Score: 3
If you want to have a look at the same pic at *much* higher resolutions than the linked site offers, check out NOAO's great image gallery here.
The rest of the gallery is worth looking at as well.
-- --
No, no gems to be found in this sig.
Re:Is Hubble So useful? Adaptive optics is cheaper
by
pavonis
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· Score: 4
Well, AO in optical wavelengths is still an immature technology, in the sense that every rigup is rather unique and experimental. It's only become really usable at all in the last year or so. And it's quite expensive too, though admittedly less so than Hubble.
It's a wonderful use of technology, and a terrific example of wholly separate fields of science aiding each other; but it's not the endall to telescopes, either. Space scopes have a number of advantages over even the best ground-based telescopes, like ESO and Keck-
You need to build a bigger scope on the ground to get the same amount of light, due to atmospheric lossage. Admittedly it's relatively easy to build big scopes on the ground.
Hubble can look at (almost) any target at any time, 24 hours a day, and it never rains up there. This means that in sheer amount of observing done, it needs to be compared to at least 3 telescopes, not just one.
Good sites for ground telescopes are in increasingly short supply, as cities spread around the world. Many, for instance, now take sites in the Chilean Andes that are about as hard to get to, and work from, as any place on Earth. That ends up costing quite a bit, too.
No ground-based scope can ever take an exposure lasting more than maybe eight hours. The Deep Field would be impossible to ever do on Earth. And the effectiveness of AO declines the longer your exposure, of course.
While, tragically, launch prices are not coming down much yet, we can at least imagine that eventually they will, and space telescopes will be cheaper.
It would be very hard, maybe impossible, to do long-baseline optical interferometry on Earth, because of things like ground tremors. It may be possible to use baselines miles long in space. This would utterly change the face of astronomy. The first test will be NASA's Terrestrial Planet Finder, sometime this decade. For optical interferometry, see Keck's web site- here.
Hubble's successor, the NGST, will actually be a near-infrared telescope. Light from very distant objects is red-shifted all the way into the infrared, so NGST will be optimized for this kind of large-scale, cosomological research. This is hard to do from the ground, as the atmosphere is a tremendous source of infrared noise even at night in cold places.
So while AO is extremely valuable, I don't think any astronomer is prepared to say "Okay, let's ditch the space telescopes now." And if you can launch them working right the first time, and don't have to foot the bill for shuttle repair missions, they are not so expensive as most folks here seem to think.
Re:the future of our eyes
by
Spagornasm
·
· Score: 3
There's a process called "interferometry." It is the combining of several smaller telescopes along the exact curvature of a larger one to produce a similar effect to the larger one. Anyone seen Contact? The VLA(where Jodie Foster heard that signal), or Very Large Array, is a series of radio telescopes layed out over almost a mile (I think) in a big peace sign. They can gather the same kind of information that a single, unimaginably more expensive telescope could.
The reason we don't have these large arrays of optical telescopes has to do with the nature of light. Radio waves have such a large wavelength that aligning several telescopes along the exact parabolic curve of a simulated large reflector is not difficult (radio waves can be anywhere from several inches to several hundred feet long).
An optical telescope array presents a much more difficult problem. Light in the visible spectrum has very small wavelengths (less than an inch). Thus, aligning even two telescopes along the proper parabolic curve for interferometry is extraordinarily difficult on earth. People are trying this with the twin 10 meter Keck telescopes in Hawaii, though, and have met with some success. The easiest place for interferometry, though, is space.
There are actually plans in NASA (I don't know if Daniel Goldin has cancelled this yet) for a few new space telescopes.
The first one is the NGST, or Next Generation Space Telescope. This will have a large solar shield (basically, a large sheet of mylar to reflect heat away from the mirrors). It will have several octagonal mirror surfaces, and will unfold to be about 8 meters across (Hubble is less than 3). It will also have various infrared and microwave cameras built in, so dangerous "upgrade" missions won't be required nearly as much.
A more long-term telescope project is under way to actually image earth-sized planets. The first will be a series of two or three small telescopes orbiting between Earth and Mars. These will be testing laser tracking and micro-rocket stability systems, and will atempt to keep the telescopes perfectly aligned down to the micrometer.
If this is successful, then a few years later a couple of telescopes the size of NGST (this is into the 2010's) will be launched and aligned in a similar manner beyond Jupiter (the plan is to spread them over about 300 meters. Imagine that - a 300 meter wide telescope, in space, without any of the distortions our atmosphere provides!). This will allow them not only an unprecedented clarity (one of the main reasons Hubble can take such amazing pictures), but also size (it could theoretically see back to half a million years after the Big Bang), and it could, of course, resolve a visual image of an earth-like planet.
Such a telescope could take the spectra of such planets. A spectrum is the rainbow you see when white light is shone through a prism. When light bounced off a certain substance is analyzed, there are dark bars present, that can tell a scientist precisely what elements (and how much of each) are present. Sometimes, in labs, scientists will burn a chunk of material with a laser, and record that (it's much brighter), but astronomers can do it with telescopes. This means that astronomers, from light years away, could tell if a planet had liquid water, oxygen, nitrogen, methane, sulfur, whatever. It is, however, highly unlikely that such a telescope could see lights at night. For one thing, it's not a given that any species would even NEED light (or that if we could detect civilization from so far away, why wouldn't we also be recieving radio or maser signals from them?). For another, just when it would be possible to see the dark side of that planet would be when it is silhouetted against its sun (imagine trying to read the date off of a dime a thousand miles away when it's held in front of a 4D flashlight).
Even further down the road (like approaching 2100) is the idea of a gravity telescope. These would be several dozen AU away (an AU, or Astronomical Unit, is the average distance from Earth to the sun, or 93,000,000 miles). These telescopes would take advantage of the fact that gravity bends light (if you ever look at some of the deep space images that the large telescopes have taken, you can see large arcs, and what look like misplaced images. These are the images of galaxies that have been bent, distorted, or magnified by either another galaxy or galaxy cluster between it and us). These gravity telescopes would be placed exactly where the gravity of the sun focuses light to a point, and thus be able to see simply unbelievable amounts of the universe. Even one of these, sweeping through a tiny arc of its several hundred year orbit, would quickly amass more information than NASA is currently capable of storing.
All in all, though, there is so much left to learn from deep space, it almost makes you cry. I find the whole endeavor rather exciting.
--
When nuance becomes the only objective we lose the ability to function
Slashdot Mirror
If I could moderate I'd mod you down to troll status. :-)
The thing about Hubble--epecially since COSTAR was installed--is that it offers extremely sharp pictures you'll never see on a ground-based telescope, even with the new telescopes going up at Mauna Kea in Hawaii and the European Southern Observatory in Chile.
The reason is simple: no atmospheric interference. Even at the high altitudes of the ground observatories I mentioned, you still have a lot of atmosphere to contend with.
Why do you think both NASA and ESA are on a fairly fast track to build more powerful space telescopes that will be launched starting late this decade?
Raymond in Mountain View, CA
Actually, the real image bank can be found here. It's got a lot of image series neatly lined up. The link in the story only shows the last (Horsehead Nebula) series.
"Hubble was launched by the shuttle Discovery on April 24, 1990. Two days later, the telescope was on its own, drifting into space, recording cosmic images."
"On its own, drifting into space, the Hubble space telescope is a reckless, lone rebel without a cause."
If you want to have a look at the same pic at *much* higher resolutions than the linked site offers, check out NOAO's great image gallery here.
The rest of the gallery is worth looking at as well.
-- No, no gems to be found in this sig.
Well, AO in optical wavelengths is still an immature technology, in the sense that every rigup is rather unique and experimental. It's only become really usable at all in the last year or so. And it's quite expensive too, though admittedly less so than Hubble.
It's a wonderful use of technology, and a terrific example of wholly separate fields of science aiding each other; but it's not the endall to telescopes, either. Space scopes have a number of advantages over even the best ground-based telescopes, like ESO and Keck-
So while AO is extremely valuable, I don't think any astronomer is prepared to say "Okay, let's ditch the space telescopes now." And if you can launch them working right the first time, and don't have to foot the bill for shuttle repair missions, they are not so expensive as most folks here seem to think.
The reason we don't have these large arrays of optical telescopes has to do with the nature of light. Radio waves have such a large wavelength that aligning several telescopes along the exact parabolic curve of a simulated large reflector is not difficult (radio waves can be anywhere from several inches to several hundred feet long).
An optical telescope array presents a much more difficult problem. Light in the visible spectrum has very small wavelengths (less than an inch). Thus, aligning even two telescopes along the proper parabolic curve for interferometry is extraordinarily difficult on earth. People are trying this with the twin 10 meter Keck telescopes in Hawaii, though, and have met with some success. The easiest place for interferometry, though, is space.
There are actually plans in NASA (I don't know if Daniel Goldin has cancelled this yet) for a few new space telescopes.
The first one is the NGST, or Next Generation Space Telescope. This will have a large solar shield (basically, a large sheet of mylar to reflect heat away from the mirrors). It will have several octagonal mirror surfaces, and will unfold to be about 8 meters across (Hubble is less than 3). It will also have various infrared and microwave cameras built in, so dangerous "upgrade" missions won't be required nearly as much.
A more long-term telescope project is under way to actually image earth-sized planets. The first will be a series of two or three small telescopes orbiting between Earth and Mars. These will be testing laser tracking and micro-rocket stability systems, and will atempt to keep the telescopes perfectly aligned down to the micrometer.
If this is successful, then a few years later a couple of telescopes the size of NGST (this is into the 2010's) will be launched and aligned in a similar manner beyond Jupiter (the plan is to spread them over about 300 meters. Imagine that - a 300 meter wide telescope, in space, without any of the distortions our atmosphere provides!). This will allow them not only an unprecedented clarity (one of the main reasons Hubble can take such amazing pictures), but also size (it could theoretically see back to half a million years after the Big Bang), and it could, of course, resolve a visual image of an earth-like planet.
Such a telescope could take the spectra of such planets. A spectrum is the rainbow you see when white light is shone through a prism. When light bounced off a certain substance is analyzed, there are dark bars present, that can tell a scientist precisely what elements (and how much of each) are present. Sometimes, in labs, scientists will burn a chunk of material with a laser, and record that (it's much brighter), but astronomers can do it with telescopes. This means that astronomers, from light years away, could tell if a planet had liquid water, oxygen, nitrogen, methane, sulfur, whatever. It is, however, highly unlikely that such a telescope could see lights at night. For one thing, it's not a given that any species would even NEED light (or that if we could detect civilization from so far away, why wouldn't we also be recieving radio or maser signals from them?). For another, just when it would be possible to see the dark side of that planet would be when it is silhouetted against its sun (imagine trying to read the date off of a dime a thousand miles away when it's held in front of a 4D flashlight).
Even further down the road (like approaching 2100) is the idea of a gravity telescope. These would be several dozen AU away (an AU, or Astronomical Unit, is the average distance from Earth to the sun, or 93,000,000 miles). These telescopes would take advantage of the fact that gravity bends light (if you ever look at some of the deep space images that the large telescopes have taken, you can see large arcs, and what look like misplaced images. These are the images of galaxies that have been bent, distorted, or magnified by either another galaxy or galaxy cluster between it and us). These gravity telescopes would be placed exactly where the gravity of the sun focuses light to a point, and thus be able to see simply unbelievable amounts of the universe. Even one of these, sweeping through a tiny arc of its several hundred year orbit, would quickly amass more information than NASA is currently capable of storing.
All in all, though, there is so much left to learn from deep space, it almost makes you cry. I find the whole endeavor rather exciting.
When nuance becomes the only objective we lose the ability to function