You can make a pretty good educated guess, or guesses. The liquid surface tension will want to pull the lens into a spherical shape, which doesn't give great imaging performance (especially off axis). Also, if only one lens is used, then you'll get chromatic distortions where your image quality depends on the wavelengths of light. I would be interested to see whether the camera phones that use these lenses give better images than those that used a fixed focus lens.
The effect of diffraction is pretty easy to calculate (assuming both your lenses are "perfect" and have circular apertures). The size of the blur spot due to diffraction is roughly 2.44*L*F, where L is the wavelength of light and F is the f-number. So, your f/29 lens has a blur spot that is a little bigger than twice that of the f/12 lens. If you are talking about a digital camera, than it is a bit simpler to compare the blur spot against the pixel size. If it is on film, then you need to compare it against the grain size distribution.
A nice quick calculation can be done if you take the good average number for the wavelength of sunlight of 500 nm (or half a micron), round down the 2.44 to 2.0, and you only need to remember that your blur spot is basically your f-number in microns.
The other guy posting is correct: refraction is only a property of the material and doesn't depend on the shape of the optic. Ultimately where the light rays go and their dependence on the shape of the optic enters into it via Snell's law.
If you take a slab of material with a constant index of refraction, you can change the path of light rays going through it by changing the shape of the surface of a material, just like you describe. Another way to do it is to take a flat slab of material, like looking into one end of a cylinder, and change the light ray paths by changing the index of refraction as you go through the material. An example of the second case is a GRIN lens. There are plenty more examples of the variable index situation, such as acoustic waves being channeled or reflected through thermal layers in the ocean or through the atmosphere.
Not only that, but it outfitted to measure the energy balance between the Earth and Sun (it would measure the Earth's albedo). That is something you can't do well from the Moon.
One of the knocks against climate warming is that some argue that the Sun is putting out more energy. This spacecraft would make that measurement, and it is bought and paid for (and built). Unfortunately some of the same people who argue that the solar output has increased are the ones refusing to launch the instrument to determine if that is the case.
The axial tilt of the Earth changes all the time. The tilt angle varies between 22 and 25 degrees over a period of about 41000 years. There is also precession of the orbit that happens on a 22000 year timescale. The changing tilt angle changes the severity of the seasons (length of seasons, ice ages, etc.), but it doesn't have anything to say about whether the planet could harbor life.
There isn't anything magical about our molten core and magnetosphere. We usually expect large rocky planets to have them, so we find it unusual if a planet doesn't have a magnetosphere.
I wouldn't say that the asteroid belt has protected us. The asteroid belt is basically a planet that either didn't form, or didn't survive. Its existence is probably one of the biggest threats to our survival on this planet. It is a race to see whether a large asteroid or comet hits our planet and wipes us out. Nobody doubts that it will happen again in the future; we just don't know when it will.
The Moon actually causes a drag on the planet that is slowing down the Earth rotation. I don't recall hearing what an ideal rotation rate for the Earth is to sustain life.
Once one gets their head around how many stars there are in just our own galaxy, many people consider it a given that there is life all around in the galaxy. Even if you take the most pessimistic odds for life to develop, once you multiply that by the number of stars out there it would seem to be very likely. The most famous statement of this is the Drake Equation. Of course, once you consider the extremely large distances between any two stars it is easy to come to the conclusion that all this life will not come in contact with each other (the intelligent life, that is).
The problem is that two researchers using the same equipment but better neutron detectors couldn't replicate the results, and these guys were from the same lab (Oak Ridge). Taleyarkhan then moves onto Purdue where the "supporting" paper comes out. The authors of that paper are Taleyarkhan's students, whom are suspected of contributing very little to the work or the paper. This is in fact the situation that you think would make a bad precedent, but it is also the reason that there was a fraud investigation (that Purdue apparently put a halt to when it appeared the investigation was going to uncover fraud).
The whole thing stinks from to to bottom because Taleyarkhan's first paper, which appeared in Science, was recommended to not be published by the to authors whom couldn't reproduce the results on the same instrument. Science ignored that, then passed the paper on to reviewers without informing them that the results couldn't be repeated. It turns out they had to pass it around to about a dozen reviewers, which is usually a bad sign because that usually means they kept hearing the thumbs-down from the reviewers. They finally decided to publish the paper under an embargo (gag order) and did so with much hoop-la and fan-fare. A better summary of events is here. Science basically dumped their scientific integrity for sensationalist headlines.
Ever since grad school I've tried to avoid any Wiley book I could because almost all of the textbooks I have come apart at the binding. I don't think this has happened to any of my other textbooks, or my Wiley paperbacks.
Were visiting dignitaries allowed a glass of wine with dinner while visiting the White House in 1978? Nope! Alcohol was banned in the White House by Carter.
I can't find any reference for that. Are you sure you are not confusing this with Rutherford Hayes' wife Lemonade Lucy in 1878?
As an avid homebrewer myself, I am certainly appreciative of Carter's signature on HR1337 in 1978 that legalized brewing beer in your home.
The pictures are amazing, but not within the context of spy satellites. The MRO orbit is only 250 to 300 km above the surface, which isn't even considered a LEO orbit on Earth.
Let's see, 30 cm resolution at 300 km works out to be a microradian angular resolution. Hubble has a resolution of 0.1 arcsec, which is like 0.5 microradians, so I suppose if you put Hubble at MRO's orbit then it would see about a factor of two better, whereas a naively one might assume a factor of 4.8 times better given that the aperture sizes on Hubble and HIRISE are 2.4 and 0.5 meters respectively. That is probably a bit of apples to oranges because I don't know in what context the Hubble resolution is. The HIRISE says it is 30 cm per pixel at 300 km, but the Hubble number I found just states it as the basic telescope resolution without mentioning whether they are talking about an Airy disk size, Rayleigh criterion, or whatever. For what it is worth, both the basic Hubble (without instruments) and HIRISE both run at f/24, so their blur spots would be comparable, so if you put the same detector behind them, they would have the same resolution.
It is different if it is not compulsory, so it depends on what X and Y are. If X is "clean up your room" and Y is "and we'll let you out of your room," then what you say applies. If X is "help me shovel out the septic tank" and Y is "and you'll get an ice cream sundae after dinner," then you are reward-based and perhaps that sundae isn't quite worth the effort you need to go through to get it.
Re:"wealthy Canadian geologist"
on
The Next X Prize
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· Score: 1
I did a Gentoo install and decided to be as up to date as I could from the start, so I did the emerge sync, world etc you listed (after running the system for several weeks). When it was done, I couldn't even boot the system to the command line. I haven't spent the time trying to dig into that mess, as that machine is a lower priority for me, but I was not terribly impressed and I'll probably consider switching over to something else. You may apparently be able to update the system easily, but I suppose you can just as easily hose your system.
Unless our understanding of gravity is WAY off here,
Of course, merging gravity and the quantum world has been one of the biggest scientific challenges for about 80 or so years, so it is safe to say that we really don't know much about gravity on these length scales.
On the other hand, there is nothing to worry about here anyway.
What I find more interesting (being a professional scientist as well, this is part of the uglier side that layman doesn't get to see much) is an interview by Owen Gingerich in this BBC article how it all went down:
Owen Gingerich chaired the IAU's planet definition committee and helped draft an initial proposal raising the number of planets from nine to 12.
The Harvard professor emeritus blamed the outcome in large part on a "revolt" by dynamicists - astronomers who study the motion and gravitational effects of celestial objects.
"In our initial proposal we took the definition of a planet that the planetary geologists would like. The dynamicists felt terribly insulted that we had not consulted with them to get their views. Somehow, there were enough of them to raise a big hue and cry," Professor Gingerich said.
"Their revolt raised enough of a fuss to destroy the scientific integrity and subtlety of the [earlier] resolution."
He added: "There were 2,700 astronomers in Prague during that 10-day period. But only 10% of them voted this afternoon. Those who disagreed and were determined to block the other resolution showed up in larger numbers than those who felt 'oh well, this is just one of those things the IAU is working on'."
To over-simplify, high resolution has nothing to do with the number of pixels, but with the size of the pixels. Take an image with 5-micron-sized pixels, even if it was 32x32 in size, and it would have better resolution than your 4000 dpi image (which works out roughly to have 6.35-micron-sized pixels).
Ultimately of course, when you are talking about imaging systems, you need to factor in the resolution limit placed by the optics, not the sensor; it wouldn't make sense to use a sensor with 10-micron-sized pixels when your lens on the front is giving you a blur spot that was 100-microns wide. I am not familiar with scanners, so I can't say how they perform and what 4000 dpi really means, but I do work with other imaging systems. You can see some very high resolution systems with one megapixel cameras or less (from the folks that do microscopy, for instance).
The consumer market gets all excited about the total number of pixels like they used to get with processor clock speed. There are many reasons most people don't need these very large arrays (such putting a crappy lens in front of it and losing your resolution), but it also never made sense to me the image sizes you get out the back. A 16M-pixel camera, with 24 bits per pixel gives a raw image size of 366 MB. To reasonably handle the images, the cameras compress the heck out of the image using a lossy algorithm (and thereby again lose image quality). In the end, at least in the consumer market, you're stuck with these larger and larger arrays because that is what they keep sticking into their newer models, so the sizes of the images we will take will just continue to grow.
I know everyone has their favorites, but I'm curious that if you were given complete control over developing a basic multi-OS application (for arugments sake, something real simple with all the usual expected GUI boxes and features), what language combo would you use?
I must profess ignorance of Ray Kurzweil and his ideas; however, though I will trust your assertion that the reasoning is straightforward, you require the reader to make three very big assumptions about technology, any of which is hard to argue on their own merits. I will also admit that I did not do anything more than a quick scan of the essay you linked to, so forgive me if some of my questions are answered in there. To start, I have a hard time thinking of anything that is truely exponential in nature because it is essentially unsustainable due to a depletion of resources. Kurzweil raises the issue then dismisses it by not addressing it. He notes that evolutionary change led to dramatic changes in organisms, such as during the Cambrian explosion, but ignores the fact that indeed species became much more complex, but they became much bigger resource depleters in that they required more food and other resources to survive. He also is very loose with "intelligence," so I am not sure how he can model it. He also seems to throw around "information" that I believe is not at all consistent with how it is usually handeled rigorously. That said, I find this argument very unconvincing, and at best some nice science fiction ideas propped up with some colorful-looking graphs.
I don't quite understand the Fermi argument either. Are there some implicit assumptions, like an infinite age of the Universe or something? To me, it sounds like arguing before Columbus sailed the Atlantic, that if there really were people on some as-yet undiscovered land over the horizon, they would already have visited Europe, therefore there isn't any race of peoples unknown.
Resolution goes as the wavelength times the f-number; you get better resolving power with smaller f-numbers. You don't need meters-sized optics because your resolution requirements are driven by the f-number. For the same f-number, the resolving power of a Hubble-sized optic and one on your cell phone camera is the same (same blur spot on the focal plane). The Hubble-sized optic has the advantage of being able to see much fainter objects because it is a much bigger light bucket.
For this sensor, it has something like 10.5k pixels per side. Spread that across 4 inches and you end up with a pixel size of about 9.5 microns. The size of the blur spot is notionally 2.44*wavelength*F/N, so if you want to put two pixels across the blur spot, you'd need an f-number (F/N) shorter than about f/15. Anything greatly shorter than that is overkill, i.e., you don't need anything like f/2 or even f/4. Finding quality lenses for a Speed Graphic that meets this is easy.
I fail to understand your argument. You are essentially arguing that there is one big pot of money set aside for "space research" and the DoD gets most of that pot. That isn't how it works. NASA is given a certain budget each year from which they divide it up amongst the various Enterprises (space science, Earth science, etc.). The DoD is given a certain budget and they decide what problems to attack depending on the perceived threat (and Congressional mandates, etc.). If the President thinks nukes launched on missiles is a major threat, they dump a lot of money into missile defense, the airborne laser, etc. If they think space-based weapons are a major threat, or a major advantage to us, they'll dump money into defending or promoting technologies to answer those issues. They are entirely separate.
I also don't understand your numbers. That $10B quoted in the article you mentioned is apparently either taken out of context, or pulled out of the air (or some one's rear). The best number I can find is $1B, and that seems to include everything, including supporting ground-based experiments, modeling, etc.
I still argue that the biggest threat to space science is an increased emphasis on the manned component. That is what is killing it.
If you lament the use of space for military uses, that is fine. If you want to argue that putting offensive or defensive weapons into space violates international treaties, that is fine. But to argue that money is being taken away from NASA, NSF, or NOAA and earmarked to go to militarizing space shows, I think, a misunderstanding of how the government budget process and prioritization operates.
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You can make a pretty good educated guess, or guesses. The liquid surface tension will want to pull the lens into a spherical shape, which doesn't give great imaging performance (especially off axis). Also, if only one lens is used, then you'll get chromatic distortions where your image quality depends on the wavelengths of light. I would be interested to see whether the camera phones that use these lenses give better images than those that used a fixed focus lens.
The effect of diffraction is pretty easy to calculate (assuming both your lenses are "perfect" and have circular apertures). The size of the blur spot due to diffraction is roughly 2.44*L*F, where L is the wavelength of light and F is the f-number. So, your f/29 lens has a blur spot that is a little bigger than twice that of the f/12 lens. If you are talking about a digital camera, than it is a bit simpler to compare the blur spot against the pixel size. If it is on film, then you need to compare it against the grain size distribution.
A nice quick calculation can be done if you take the good average number for the wavelength of sunlight of 500 nm (or half a micron), round down the 2.44 to 2.0, and you only need to remember that your blur spot is basically your f-number in microns.
They have them now. The going price for them in is the neighborhood of Six Million Dollars.
Unless you are designing a hydraulic system.
The other guy posting is correct: refraction is only a property of the material and doesn't depend on the shape of the optic. Ultimately where the light rays go and their dependence on the shape of the optic enters into it via Snell's law.
If you take a slab of material with a constant index of refraction, you can change the path of light rays going through it by changing the shape of the surface of a material, just like you describe. Another way to do it is to take a flat slab of material, like looking into one end of a cylinder, and change the light ray paths by changing the index of refraction as you go through the material. An example of the second case is a GRIN lens. There are plenty more examples of the variable index situation, such as acoustic waves being channeled or reflected through thermal layers in the ocean or through the atmosphere.
That same summary also said that these Germans designed the first liquid lenses. Those Samsung guys must do a pretty quick turnaround.
Not only that, but it outfitted to measure the energy balance between the Earth and Sun (it would measure the Earth's albedo). That is something you can't do well from the Moon.
One of the knocks against climate warming is that some argue that the Sun is putting out more energy. This spacecraft would make that measurement, and it is bought and paid for (and built). Unfortunately some of the same people who argue that the solar output has increased are the ones refusing to launch the instrument to determine if that is the case.
I think you need to recheck some of your facts.
Our solar system moves in and out of the spiral arms as well as up and down through the galactic plane. We go through the galactic plane about every 35 million years, and through the spiral arms about every 100 million years. Some postulate that these timescales coincide with various mass extinctions that occurred.
The axial tilt of the Earth changes all the time. The tilt angle varies between 22 and 25 degrees over a period of about 41000 years. There is also precession of the orbit that happens on a 22000 year timescale. The changing tilt angle changes the severity of the seasons (length of seasons, ice ages, etc.), but it doesn't have anything to say about whether the planet could harbor life.
There isn't anything magical about our molten core and magnetosphere. We usually expect large rocky planets to have them, so we find it unusual if a planet doesn't have a magnetosphere.
I wouldn't say that the asteroid belt has protected us. The asteroid belt is basically a planet that either didn't form, or didn't survive. Its existence is probably one of the biggest threats to our survival on this planet. It is a race to see whether a large asteroid or comet hits our planet and wipes us out. Nobody doubts that it will happen again in the future; we just don't know when it will.
The Moon actually causes a drag on the planet that is slowing down the Earth rotation. I don't recall hearing what an ideal rotation rate for the Earth is to sustain life.
Once one gets their head around how many stars there are in just our own galaxy, many people consider it a given that there is life all around in the galaxy. Even if you take the most pessimistic odds for life to develop, once you multiply that by the number of stars out there it would seem to be very likely. The most famous statement of this is the Drake Equation. Of course, once you consider the extremely large distances between any two stars it is easy to come to the conclusion that all this life will not come in contact with each other (the intelligent life, that is).
The problem is that two researchers using the same equipment but better neutron detectors couldn't replicate the results, and these guys were from the same lab (Oak Ridge). Taleyarkhan then moves onto Purdue where the "supporting" paper comes out. The authors of that paper are Taleyarkhan's students, whom are suspected of contributing very little to the work or the paper. This is in fact the situation that you think would make a bad precedent, but it is also the reason that there was a fraud investigation (that Purdue apparently put a halt to when it appeared the investigation was going to uncover fraud).
The whole thing stinks from to to bottom because Taleyarkhan's first paper, which appeared in Science, was recommended to not be published by the to authors whom couldn't reproduce the results on the same instrument. Science ignored that, then passed the paper on to reviewers without informing them that the results couldn't be repeated. It turns out they had to pass it around to about a dozen reviewers, which is usually a bad sign because that usually means they kept hearing the thumbs-down from the reviewers. They finally decided to publish the paper under an embargo (gag order) and did so with much hoop-la and fan-fare. A better summary of events is here. Science basically dumped their scientific integrity for sensationalist headlines.
Ever since grad school I've tried to avoid any Wiley book I could because almost all of the textbooks I have come apart at the binding. I don't think this has happened to any of my other textbooks, or my Wiley paperbacks.
I can't find any reference for that. Are you sure you are not confusing this with Rutherford Hayes' wife Lemonade Lucy in 1878?
As an avid homebrewer myself, I am certainly appreciative of Carter's signature on HR1337 in 1978 that legalized brewing beer in your home.
You mean you don't want to use this link: :)
TrustLet's see, 30 cm resolution at 300 km works out to be a microradian angular resolution. Hubble has a resolution of 0.1 arcsec, which is like 0.5 microradians, so I suppose if you put Hubble at MRO's orbit then it would see about a factor of two better, whereas a naively one might assume a factor of 4.8 times better given that the aperture sizes on Hubble and HIRISE are 2.4 and 0.5 meters respectively. That is probably a bit of apples to oranges because I don't know in what context the Hubble resolution is. The HIRISE says it is 30 cm per pixel at 300 km, but the Hubble number I found just states it as the basic telescope resolution without mentioning whether they are talking about an Airy disk size, Rayleigh criterion, or whatever. For what it is worth, both the basic Hubble (without instruments) and HIRISE both run at f/24, so their blur spots would be comparable, so if you put the same detector behind them, they would have the same resolution.
It is different if it is not compulsory, so it depends on what X and Y are. If X is "clean up your room" and Y is "and we'll let you out of your room," then what you say applies. If X is "help me shovel out the septic tank" and Y is "and you'll get an ice cream sundae after dinner," then you are reward-based and perhaps that sundae isn't quite worth the effort you need to go through to get it.
Just like these.
I did a Gentoo install and decided to be as up to date as I could from the start, so I did the emerge sync, world etc you listed (after running the system for several weeks). When it was done, I couldn't even boot the system to the command line. I haven't spent the time trying to dig into that mess, as that machine is a lower priority for me, but I was not terribly impressed and I'll probably consider switching over to something else. You may apparently be able to update the system easily, but I suppose you can just as easily hose your system.
If they ever launch the darn thing (it is supposed to go up on the Falcon), this linux-run satellite has been ready to go for years.
Of course, merging gravity and the quantum world has been one of the biggest scientific challenges for about 80 or so years, so it is safe to say that we really don't know much about gravity on these length scales.
On the other hand, there is nothing to worry about here anyway.
To over-simplify, high resolution has nothing to do with the number of pixels, but with the size of the pixels. Take an image with 5-micron-sized pixels, even if it was 32x32 in size, and it would have better resolution than your 4000 dpi image (which works out roughly to have 6.35-micron-sized pixels).
Ultimately of course, when you are talking about imaging systems, you need to factor in the resolution limit placed by the optics, not the sensor; it wouldn't make sense to use a sensor with 10-micron-sized pixels when your lens on the front is giving you a blur spot that was 100-microns wide. I am not familiar with scanners, so I can't say how they perform and what 4000 dpi really means, but I do work with other imaging systems. You can see some very high resolution systems with one megapixel cameras or less (from the folks that do microscopy, for instance).
The consumer market gets all excited about the total number of pixels like they used to get with processor clock speed. There are many reasons most people don't need these very large arrays (such putting a crappy lens in front of it and losing your resolution), but it also never made sense to me the image sizes you get out the back. A 16M-pixel camera, with 24 bits per pixel gives a raw image size of 366 MB. To reasonably handle the images, the cameras compress the heck out of the image using a lossy algorithm (and thereby again lose image quality). In the end, at least in the consumer market, you're stuck with these larger and larger arrays because that is what they keep sticking into their newer models, so the sizes of the images we will take will just continue to grow.
I know everyone has their favorites, but I'm curious that if you were given complete control over developing a basic multi-OS application (for arugments sake, something real simple with all the usual expected GUI boxes and features), what language combo would you use?
I must profess ignorance of Ray Kurzweil and his ideas; however, though I will trust your assertion that the reasoning is straightforward, you require the reader to make three very big assumptions about technology, any of which is hard to argue on their own merits. I will also admit that I did not do anything more than a quick scan of the essay you linked to, so forgive me if some of my questions are answered in there. To start, I have a hard time thinking of anything that is truely exponential in nature because it is essentially unsustainable due to a depletion of resources. Kurzweil raises the issue then dismisses it by not addressing it. He notes that evolutionary change led to dramatic changes in organisms, such as during the Cambrian explosion, but ignores the fact that indeed species became much more complex, but they became much bigger resource depleters in that they required more food and other resources to survive. He also is very loose with "intelligence," so I am not sure how he can model it. He also seems to throw around "information" that I believe is not at all consistent with how it is usually handeled rigorously. That said, I find this argument very unconvincing, and at best some nice science fiction ideas propped up with some colorful-looking graphs.
I don't quite understand the Fermi argument either. Are there some implicit assumptions, like an infinite age of the Universe or something? To me, it sounds like arguing before Columbus sailed the Atlantic, that if there really were people on some as-yet undiscovered land over the horizon, they would already have visited Europe, therefore there isn't any race of peoples unknown.
Resolution goes as the wavelength times the f-number; you get better resolving power with smaller f-numbers. You don't need meters-sized optics because your resolution requirements are driven by the f-number. For the same f-number, the resolving power of a Hubble-sized optic and one on your cell phone camera is the same (same blur spot on the focal plane). The Hubble-sized optic has the advantage of being able to see much fainter objects because it is a much bigger light bucket.
For this sensor, it has something like 10.5k pixels per side. Spread that across 4 inches and you end up with a pixel size of about 9.5 microns. The size of the blur spot is notionally 2.44*wavelength*F/N, so if you want to put two pixels across the blur spot, you'd need an f-number (F/N) shorter than about f/15. Anything greatly shorter than that is overkill, i.e., you don't need anything like f/2 or even f/4. Finding quality lenses for a Speed Graphic that meets this is easy.
Just like "white" incoherent light from a projector: you mix the R, G, and B.
I fail to understand your argument. You are essentially arguing that there is one big pot of money set aside for "space research" and the DoD gets most of that pot. That isn't how it works. NASA is given a certain budget each year from which they divide it up amongst the various Enterprises (space science, Earth science, etc.). The DoD is given a certain budget and they decide what problems to attack depending on the perceived threat (and Congressional mandates, etc.). If the President thinks nukes launched on missiles is a major threat, they dump a lot of money into missile defense, the airborne laser, etc. If they think space-based weapons are a major threat, or a major advantage to us, they'll dump money into defending or promoting technologies to answer those issues. They are entirely separate.
I also don't understand your numbers. That $10B quoted in the article you mentioned is apparently either taken out of context, or pulled out of the air (or some one's rear). The best number I can find is $1B, and that seems to include everything, including supporting ground-based experiments, modeling, etc.
I still argue that the biggest threat to space science is an increased emphasis on the manned component. That is what is killing it.
If you lament the use of space for military uses, that is fine. If you want to argue that putting offensive or defensive weapons into space violates international treaties, that is fine. But to argue that money is being taken away from NASA, NSF, or NOAA and earmarked to go to militarizing space shows, I think, a misunderstanding of how the government budget process and prioritization operates.