and what iluminates it? It's bright enough to see with a telescope, but it's -272?
From the article:
"One can say the Boomerang acts as a refrigerator," said astronomer Lars-Ake Nyman, who measured its temperature using the European Southern Observatory radio telescope in Chile. He did this by comparing signals received from carbon monoxide in the nebula with signals from the background radiation.
So it was done with a radio telescope, possibly SEST, by looking at molecular lines from CO. It sounds like they found that the CO was absorbing some of the background radiation. So it wasn't "seen" with a telescope in the way that you're thinking.
that's cool. What sort of astrnomy can be done with this?
I work for an observatory that uses these wavelengths to do astronomy. At these wavelengths you're mostly looking at the cold material in the universe --- stuff like interstellar gas, dust, and so on.
Re:Another review nicked off amazon
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Kiln People
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Well, maybe it's not plagiarism - maybe she's just created a ditto of the original review, in the spirit of the book?:-)
Another down side is that your at 13,800 ft. The air is very thin and altitude sickness is very very common. Not to mention that it is extremely cold up there.
Very true, although Keck do remote observing from the much more comfortable environment of Waimea. From the auction:
The observatory headquarters, Visiting Scientists' Quarters, and control rooms are located in Waimea, at about 2,500 feet.
If the sound does become a problem, how about adding a little sound proof (dampening) enclosure around it?
I have my hard drive in an acoustic enclosure from www.quietpc.com, and have been very happy with it. The only drawbacks are that hotter drives may overheat, and you need to put the whole thing in a 5.25" drive bay.
The image of the dust around Epsilon Eridani shown in the article is a false colour submillimetre wavelength image made with SCUBA on the James Clerk Maxwell Telescope in Hawaii. The work described here seems to be computer simulations which tie in with the observations.
I don't have the equation for the gravitational attraction between two bodies. But I know it is a function of the SUM of the masses of the two objects.
Err... the force is proportional to the product of the two masses: F = -G M m / r^2;... not the sum.
Sorry if my original reply was a bit terse - it was the middle of the night here!:-) On re-reading it I sound a bit brusque.
Another way of thinking about it is indeed very much like the wave of a boat... the thing is that the variations in the detection of the disk (this 'wake') are probably due to varying amounts of 'stuff' rather than the differing brightness or darkness of the stuff. So this dust, which is dark in visible light but bright in submillimetre light, is also 'piling up' in certain places around the star due to the gravity of this inferred planet.
Not really. I'm not great on thermodynamics but I don't think anything can get to absolute zero. If there's literally nothing in a bit of space, then it doesn't have a temperature at all. You're right though that the dust is warmer than the 3K microwave background.
The fact that this stuff is less warm than planets and less warm than stars means it shows up on its own.
The fact that it has a temperature at all means it emits radiation, and hence shows up. You just need the right sort of telescope and detector (JCMT and SCUBA in this case) to detect it.
So the "wake" they describe sounds more like a shadow.
"Our models of the Fomalhaut disk suggest that a planet similar in mass to Saturn is creating a wake or trail of dust", says team member Dr. Mark Wyatt. "The gravity of the planet creates points near its orbit called 'resonances' where comets get trapped.
So it's a gravitational effect, not an optical shadow.
kelvin is based on the theoratical temperature of absolute zero, which would be equivalent to 0 kelvin, or -273 degrees celsius. therefore, 273 kelvin is equal to 0 degrees celsius and 373 kelvin is 100 degrees celsius.
Not really, because 0K is not exactly -273C. It's something more like -273.15K. That number's from memory though...
anyone know anything at all about telescopes and the like as to why Hubble wasn't able to see this before?
I work for the Joint Astronomy Centre, who operate both SCUBA and the James Clerk Maxwell Telescope. Hubble is a telescope that operates in an entirely different wavelength range (optical, infrared), whilst the JCMT and SCUBA work at submillimetre wavelengths. SCUBA's looking at interstellar dust particles. At Hubble's wavelengths this dust just has an absorbing and obscuring effect, so you can't see it properly. However, SCUBA sees the heat glow from it.
If you go out on a clear night and look at Sagittarius, you're looking towards the centre of the Milky Way. You'll see lots of dark patches among the brightness, which are caused by the extinction of starlight by this interstellar dust. Because it's dark, you can't properly see it. However, if you could see with SCUBA's eyes you'd see this stuff glowing brightly!
i thought that space was absolute zero for temperature, or at least something remarkably close. how in the world are they able to get something colder on earth than they can in space?
Low temperature physicists make things colder than this all the time - the same way that we can make things colder than the ambient temperature on Earth.
From memory, so might be wrong: In SCUBA's case, we use a vacuum jacket, then liquid nitrogen, then liquid helium, and then what's known as a dilution refrigerator (which I won't even pretend to understand!). It involves a mixture of liquid He3 and He4 I think. Gets us down to under 100mK.
Although experiments do go quite a bit colder, in terms of its size and the fact that it runs for extended periods at this temperature, SCUBA is one of the coldest fridges in the world.
I work for the organisation that operates SCUBA and the James Clerk Maxwell Telescope.
The "A" in SCUBA stands for array - This means that SCUBA is actually a collection of telescopes spread out to form the equivalent of a very large telescope.
No - you're thinking of interferometer arrays. In this case SCUBA stands for Submillimetre Common-User Bolometer Array:
Submillimetre: the wavelength of the light we detect.
Common-User: open to the general research community
Bolometer Array: has multiple bolometers, which are the detector elements, in the same way that a CCD is an array of individual pixel detectors. Each bolometer is (if I remember correctly) a tiny chip of neutron transmutation doped germanium on a bismuth/sapphire substrate. They work a bit like very sensitive thermistors.
(Imagine computing devices that communicate seamlessly across the entire electromagnetic spectrum.)
Okay, I'm imagining it. But that's not what this is, right (even though it's a cool project)? Radio's just a tiny part of the electromagnetic spectrum. This presumably isn't going to be transmitting in visible light, let alone hard X-rays and gamma rays.
Wasn't there a recent story here about developing a multiple-mirrored telescope to allow high resoultion images of deep space? Some of the discussion even mentioned the notion of placing individual mirror elements in different places around the world to help improve resolution. Such a scope is harder to use than a single curved mirror (despite the cost savings) due to image distortion. I would think this kind of technology would be perfect for something like that...
This requires knowledge of the phase of the light rather than just its amplitude or power, which is all you get from normal video cameras. Also, interferometry increases your resolution but not your field of view, i.e. it's closest to the part of the article about zooming in, not panning around. To use the technique in the article you'd have to build bigger telescopes to get the improved resolution, which is what astronomers try to do anyway.
If you're talking about combining lots of images from the same vantage point in order to improve your field of view, astronomers do this mosaicing all the time. For some of my work on the Galactic Centre I was using an instrument with a small field of view (a thirtieth of a degree), and I had to pan the telescope as well as stitch multiple observations together to get the full map which was still only a few degrees across (the size of a few full moons).
It might not be provable in a formal logic sense, but it is a useful way of thinking about scientific theories. Occam's Razor is more often quoted as "Entities should not be multiplied unnecessarily". It's interesting that you use the example of quantum physics, as it has been used here, too.
Although you're implying that Quantum Physics is much more complex than Classical Physics, a quantum theory is necessary to explain observable phenomena. The Schrodinger equation is, in its own way, elegant and simple, and models quantum behaviour better than an ad hoc set of modifications to classical theories.
But I won't buy the watch-sized cell phone. Unless the phone is somehow implanted, anything smaller than an existing phone isn't going to be convenient for people to talk into or dial out of.
You might well be right, but people are investigating ways to get around this. There's a prototype phone where you stick your finger in your ear to listen to vibrations, and talk into its wrist mic (no, really!:-).
Maybe part of the problem is that computers and other electronic devices are genuinely very complicated things, and we are still learning how to make them easier to use. However, the marketing department sells them as "Your Plastic Pal who's fun to be with!" People have expectations which they wouldn't have if they had bought a fighter jet, MRI scanner, or orbiting space telescope.
I'm very much in favour of making things easy to use, but you've really got to make the user-friendly wizardly do its job and work robustly. It's no use having lots of wizards they can't automate the task adequately, or if you get cryptic "An error occurred." messages.
Some people prefer a manual transmission car to an automatic, or vice-versa. Automatics do a reasonable job, even though a manual gives you more control. But if computer companies made them, the slogan would say "With our new IntelliShift gearbox you'll never need to use the clutch again!" - and then your car would suddenly downshift to first when you're doing 70mph.
Slashdot Mirror
Ahem. Except that the Latin for 'book' is (I believe) 'liber', from which we get words like library.
You are thinking of the Greek 'biblos'. 'Bibliography' comes from that and the Greek 'graphein', 'to write'.
But you're right. An understanding of Latin and Greek does help :)
From the article:
So it was done with a radio telescope, possibly SEST, by looking at molecular lines from CO. It sounds like they found that the CO was absorbing some of the background radiation. So it wasn't "seen" with a telescope in the way that you're thinking.
It's because the cosmic microwave background has the spectrum of a blackbody with the given temperature (2.7K).
I work for an observatory that uses these wavelengths to do astronomy. At these wavelengths you're mostly looking at the cold material in the universe --- stuff like interstellar gas, dust, and so on.
Well, maybe it's not plagiarism - maybe she's just created a ditto of the original review, in the spirit of the book? :-)
I don't think it's just at altitude, to be honest :-)
Very true, although Keck do remote observing from the much more comfortable environment of Waimea. From the auction:
Yeah, and you wouldn't want to go down with a case of heavy metal poisoning.
I have my hard drive in an acoustic enclosure from www.quietpc.com, and have been very happy with it. The only drawbacks are that hotter drives may overheat, and you need to put the whole thing in a 5.25" drive bay.
The image of the dust around Epsilon Eridani shown in the article is a false colour submillimetre wavelength image made with SCUBA on the James Clerk Maxwell Telescope in Hawaii. The work described here seems to be computer simulations which tie in with the observations.
You can find out more about those observations of Eps Eri, and of similar evidence for extrasolar planets around Vega and Fomalhaut at the Joint Astronomy Centre, who run the JCMT and for whom I work.
These are the same sort of observations that revealed the 'wake' around Fomalhaut that was covered recently here on Slashdot in 'Looking for intelligence'.
Err... the force is proportional to the product of the two masses: F = -G M m / r^2; ... not the sum.
This might be a misinterpretation. In the ESO press release they say:
So that puts an upper limit on the scale of the thing, but doesn't imply it takes up all of that space.
Sorry if my original reply was a bit terse - it was the middle of the night here! :-) On re-reading it I sound a bit brusque.
Another way of thinking about it is indeed very much like the wave of a boat... the thing is that the variations in the detection of the disk (this 'wake') are probably due to varying amounts of 'stuff' rather than the differing brightness or darkness of the stuff. So this dust, which is dark in visible light but bright in submillimetre light, is also 'piling up' in certain places around the star due to the gravity of this inferred planet.
Not really. I'm not great on thermodynamics but I don't think anything can get to absolute zero. If there's literally nothing in a bit of space, then it doesn't have a temperature at all. You're right though that the dust is warmer than the 3K microwave background.
The fact that it has a temperature at all means it emits radiation, and hence shows up. You just need the right sort of telescope and detector (JCMT and SCUBA in this case) to detect it.
No. From the press release:
So it's a gravitational effect, not an optical shadow.
Not really, because 0K is not exactly -273C. It's something more like -273.15K. That number's from memory though...
I work for the Joint Astronomy Centre, who operate both SCUBA and the James Clerk Maxwell Telescope. Hubble is a telescope that operates in an entirely different wavelength range (optical, infrared), whilst the JCMT and SCUBA work at submillimetre wavelengths. SCUBA's looking at interstellar dust particles. At Hubble's wavelengths this dust just has an absorbing and obscuring effect, so you can't see it properly. However, SCUBA sees the heat glow from it.
If you go out on a clear night and look at Sagittarius, you're looking towards the centre of the Milky Way. You'll see lots of dark patches among the brightness, which are caused by the extinction of starlight by this interstellar dust. Because it's dark, you can't properly see it. However, if you could see with SCUBA's eyes you'd see this stuff glowing brightly!
Low temperature physicists make things colder than this all the time - the same way that we can make things colder than the ambient temperature on Earth.
From memory, so might be wrong: In SCUBA's case, we use a vacuum jacket, then liquid nitrogen, then liquid helium, and then what's known as a dilution refrigerator (which I won't even pretend to understand!). It involves a mixture of liquid He3 and He4 I think. Gets us down to under 100mK.
Although experiments do go quite a bit colder, in terms of its size and the fact that it runs for extended periods at this temperature, SCUBA is one of the coldest fridges in the world.
(I work for the Joint Astronomy Centre who operate SCUBA and the James Clerk Maxwell Telescope.)
I work for the organisation that operates SCUBA and the James Clerk Maxwell Telescope.
No - you're thinking of interferometer arrays. In this case SCUBA stands for Submillimetre Common-User Bolometer Array:
That spin on it seems to have come from the newspaper. I work for one of the organisations involved, and you can see the original press release on our website.
Okay, I'm imagining it. But that's not what this is, right (even though it's a cool project)? Radio's just a tiny part of the electromagnetic spectrum. This presumably isn't going to be transmitting in visible light, let alone hard X-rays and gamma rays.
Not really, unfortunately. You're thinking of interferometry or aperture synthesis, which can also be done with light.
This requires knowledge of the phase of the light rather than just its amplitude or power, which is all you get from normal video cameras. Also, interferometry increases your resolution but not your field of view, i.e. it's closest to the part of the article about zooming in, not panning around. To use the technique in the article you'd have to build bigger telescopes to get the improved resolution, which is what astronomers try to do anyway.
If you're talking about combining lots of images from the same vantage point in order to improve your field of view, astronomers do this mosaicing all the time. For some of my work on the Galactic Centre I was using an instrument with a small field of view (a thirtieth of a degree), and I had to pan the telescope as well as stitch multiple observations together to get the full map which was still only a few degrees across (the size of a few full moons).
It might not be provable in a formal logic sense, but it is a useful way of thinking about scientific theories. Occam's Razor is more often quoted as "Entities should not be multiplied unnecessarily". It's interesting that you use the example of quantum physics, as it has been used here, too.
Although you're implying that Quantum Physics is much more complex than Classical Physics, a quantum theory is necessary to explain observable phenomena. The Schrodinger equation is, in its own way, elegant and simple, and models quantum behaviour better than an ad hoc set of modifications to classical theories.
You might well be right, but people are investigating ways to get around this. There's a prototype phone where you stick your finger in your ear to listen to vibrations, and talk into its wrist mic (no, really! :-).
Maybe part of the problem is that computers and other electronic devices are genuinely very complicated things, and we are still learning how to make them easier to use. However, the marketing department sells them as "Your Plastic Pal who's fun to be with!" People have expectations which they wouldn't have if they had bought a fighter jet, MRI scanner, or orbiting space telescope.
I'm very much in favour of making things easy to use, but you've really got to make the user-friendly wizardly do its job and work robustly. It's no use having lots of wizards they can't automate the task adequately, or if you get cryptic "An error occurred." messages.
Some people prefer a manual transmission car to an automatic, or vice-versa. Automatics do a reasonable job, even though a manual gives you more control. But if computer companies made them, the slogan would say "With our new IntelliShift gearbox you'll never need to use the clutch again!" - and then your car would suddenly downshift to first when you're doing 70mph.
I believe Clifford Stoll (of Cuckoo's Egg fame) makes them out of glass. See www.kleinbottle.com.