Know what the biggest difference is between generic amateur snapshots and wow photos?
Depth of field.
The awesome photos are almost never the ones with everything in focus. But if you really want that, the cheaper your camera the more likely it is to achieve it.
Due to the way it works, light field cameras will always have a fraction of the resolution of regular cameras and/or poorer low light performance. Really, poor focus isn't usually a problem with modern cameras. Most of the shots people think are poorly focused are probably actually motion blurred because the camera had to use too slow a shutter speed in order to make up for it's crappy low light performance. And this camera is worse.
I think the article had it right, sort of: these are bound to be embedded in certain specialty devices. They're great for 3D capture, for example. It's not going to make it as a camera on it's own. People who pay a lot for cameras generally lust after shallow depth of field for it's artistic effects. People who don't use whatever camera is at hand, usually the one in their cell phones.
"You sure about that? Because the Space Shuttle reached orbit much faster than 5 minutes, so it seems like the acceleration should be somewhat more than this train (of course, the train is also traveling laterally some distance, so that would probably account for it)."
Yes. And no, the space shuttle took longer than 5 minutes to reach orbit, and took a big shortcut by going straight up for the first bit. Haven't you ever watched a launch?
No, the proposal for this thing is as big as it is specifically so that people can ride it. But it very well might make the average person "shit his pants" as the OP said. As for space elevators, they are currently impossible, whereas this thing is probably possible to build. Also, a ride up a space elevator might take a couple of weeks, while this thing gets you there in 5 minutes. As for energy, it's levitated with superconductors, so there is no ongoing energy cost except for the cryogenics, and if the power fails, well, nothing happens.
A military one can be a lot shorter if you don't want to launch people. Iran even has some decent mountains, although if you were throwing rocks you wouldn't need to elevate it much.
"This thing would be far easier to build on Moon where gravitation is much lower and there is no atmosphere."
You know, it would be even easier to build it in orbit. It could be much smaller too, because getting to orbit requires much less delta v when you're already in orbit!
In other words, you have no idea. It might be a problem, it might not. Replacing a 20 km line isn't that hard, especially when you can drive up and drop it off. Regardless of the material, suspending 4 tons doesn't sound so impossible.
"There is so much energy in the coils that sparks are forming that are welding the shuttle to the rails. "
There isn't any extra energy involved in going faster when you're in a vacuum. If you can produce the acceleration, that and the length of track is all that matters.
It's levitated using a superconductor. There are no power requirements once you have it powered up. Well, you need some power to keep the superconductor cold, but that's it.
Yes, a big magnet on the ground repelling a big magnet in the air. Since the magnets are actually very long superconducting wires the intensity of the field reduces more or less linearly.
The shuttle cost about half a billion dollars to launch. Satellites that can do most of those things can be built as class projects in high school.
Rentry and human rated space capsules are a little harder, but still cheap compared to the infrastructure, design and effort (yes, fuel is not the only part, but all those launch costs go away) of actually launching anything.
"ohmygod. I want some of whatever they're smoking. At those low, low prices, everybody can have one."
That's kind of the point. We spend more than an order of magnitude more than that on rockets NOW. IIRC Americans spend more than that on cosmetics, every year. It's also such a tiny fraction of the US defence budget that it probably wouldn't even be missed (literally).
They said 3 g forward on the way up, 3 g backward when you hit the atmosphere. So on the way up you're in the tightest turn you've ever felt on a roller coaster for 5 minutes straight, then you suddenly get to experience it in exactly the opposite direction.
It would be a pretty wild ride. Nothing a reasonably healthy person couldn't take, but it would scare the hell out of most of the population.
The space shuttle, for comparison, had a maximum acceleration of about 3 g. So it would be like a shuttle ride, except for that 6 g switch when you slam into the atmosphere.
Hm... 60 billion over twenty years. That's well within the military budget of Iran, and would be child's play for China. You could use this thing to put stuff in orbit, quickly, which obviously has military uses, and it would double as an awesome artillery piece that could reach nearly anywhere in the world. Iraq tried to build a mega-gun once. It would be an excellent demonstration of Chinese superiority.
"It's not a type of interferometry as they don't measure phase-shifts directly."
Interferometry is traditionally done by looking at interference patterns (which is what a diffraction pattern is). That's why it's called interferometry. It's only quite recently that we've been able to (sort of) measure the phase of light at reasonably high frequencies.
You're right, MRI (or nMRI) is nMR (Imaging). But the first poster said nMR and I wasn't feeling pedantic enough to contradict him. I really don't see how you'd use this at all if you weren't imaging.
In MRI you create an image by manipulating the relative phase of atomic nuclei with net magnetic moments. You measure the resulting interference for a bunch of different relative phases, then Fourier transform to get an image. It's interferometric imaging, except you're manipulating the phase instead of the sensor positions (as in radio interferometric imaging).
You're right, it does look similar to phase contrast CT. I'm not sure it's quite the same thing as they're doing here, but that's because the article on this technique isn't very clear.
It's already happened. But so what? I hate to tell you, but most people use their computers for surfing the web, Skype and maybe some e-mail.
I took mine on a trip to Europe last year instead of my notebook. It was slightly more awkward to do a few things but MUCH easier to carry. I wouldn't want to switch to an iPad exclusively, but for 90% of the people I know a tablet would probably be fine for their only personal computer.
A little bit of practice and you can get pretty damned fast. I wouldn't want to write a paper on it (yet), but I've found myself not bothering to open the notebook to answer most e-mail. I can probably do about half my keyboard typing speed on it... say 40 wpm.
Slashdot Mirror
Know what the biggest difference is between generic amateur snapshots and wow photos?
Depth of field.
The awesome photos are almost never the ones with everything in focus. But if you really want that, the cheaper your camera the more likely it is to achieve it.
The people who spend lots of money on cameras want shallow depth of field and selective focus. That's why they spend even more money on lenses.
Due to the way it works, light field cameras will always have a fraction of the resolution of regular cameras and/or poorer low light performance. Really, poor focus isn't usually a problem with modern cameras. Most of the shots people think are poorly focused are probably actually motion blurred because the camera had to use too slow a shutter speed in order to make up for it's crappy low light performance. And this camera is worse.
I think the article had it right, sort of: these are bound to be embedded in certain specialty devices. They're great for 3D capture, for example. It's not going to make it as a camera on it's own. People who pay a lot for cameras generally lust after shallow depth of field for it's artistic effects. People who don't use whatever camera is at hand, usually the one in their cell phones.
Because images where everything is sharp look just like the ones you take with a cheap cell phone.
"You sure about that? Because the Space Shuttle reached orbit much faster than 5 minutes, so it seems like the acceleration should be somewhat more than this train (of course, the train is also traveling laterally some distance, so that would probably account for it)."
Yes. And no, the space shuttle took longer than 5 minutes to reach orbit, and took a big shortcut by going straight up for the first bit. Haven't you ever watched a launch?
http://en.wikipedia.org/wiki/Orders_of_magnitude_(acceleration)
http://en.wikipedia.org/wiki/Space_Shuttle#Launch
No, the proposal for this thing is as big as it is specifically so that people can ride it. But it very well might make the average person "shit his pants" as the OP said. As for space elevators, they are currently impossible, whereas this thing is probably possible to build. Also, a ride up a space elevator might take a couple of weeks, while this thing gets you there in 5 minutes. As for energy, it's levitated with superconductors, so there is no ongoing energy cost except for the cryogenics, and if the power fails, well, nothing happens.
A military one can be a lot shorter if you don't want to launch people. Iran even has some decent mountains, although if you were throwing rocks you wouldn't need to elevate it much.
"This thing would be far easier to build on Moon where gravitation is much lower and there is no atmosphere."
You know, it would be even easier to build it in orbit. It could be much smaller too, because getting to orbit requires much less delta v when you're already in orbit!
"How often is a factor of tension and heat."
In other words, you have no idea. It might be a problem, it might not. Replacing a 20 km line isn't that hard, especially when you can drive up and drop it off. Regardless of the material, suspending 4 tons doesn't sound so impossible.
"There is so much energy in the coils that sparks are forming that are welding the shuttle to the rails. "
There isn't any extra energy involved in going faster when you're in a vacuum. If you can produce the acceleration, that and the length of track is all that matters.
It's levitated using a superconductor. There are no power requirements once you have it powered up. Well, you need some power to keep the superconductor cold, but that's it.
It's a superconductor. You don't keep pumping power into it.
If your superconductor somehow quenched then you'd have all sorts of problems, which is why they propose using lots of independent, redundant ones.
Yes, a big magnet on the ground repelling a big magnet in the air. Since the magnets are actually very long superconducting wires the intensity of the field reduces more or less linearly.
Presumably you'd build this thing in a desert somewhere. Real estate is a lot cheaper.
The shuttle cost about half a billion dollars to launch. Satellites that can do most of those things can be built as class projects in high school.
Rentry and human rated space capsules are a little harder, but still cheap compared to the infrastructure, design and effort (yes, fuel is not the only part, but all those launch costs go away) of actually launching anything.
"ohmygod. I want some of whatever they're smoking. At those low, low prices, everybody can have one."
That's kind of the point. We spend more than an order of magnitude more than that on rockets NOW. IIRC Americans spend more than that on cosmetics, every year. It's also such a tiny fraction of the US defence budget that it probably wouldn't even be missed (literally).
They said 3 g forward on the way up, 3 g backward when you hit the atmosphere. So on the way up you're in the tightest turn you've ever felt on a roller coaster for 5 minutes straight, then you suddenly get to experience it in exactly the opposite direction.
It would be a pretty wild ride. Nothing a reasonably healthy person couldn't take, but it would scare the hell out of most of the population.
The space shuttle, for comparison, had a maximum acceleration of about 3 g. So it would be like a shuttle ride, except for that 6 g switch when you slam into the atmosphere.
I'd suggest not standing too close to the 100 million amp cable, actually, regardless of the magnetic field.
Hm... 60 billion over twenty years. That's well within the military budget of Iran, and would be child's play for China. You could use this thing to put stuff in orbit, quickly, which obviously has military uses, and it would double as an awesome artillery piece that could reach nearly anywhere in the world. Iraq tried to build a mega-gun once. It would be an excellent demonstration of Chinese superiority.
"It's not a type of interferometry as they don't measure phase-shifts directly."
Interferometry is traditionally done by looking at interference patterns (which is what a diffraction pattern is). That's why it's called interferometry. It's only quite recently that we've been able to (sort of) measure the phase of light at reasonably high frequencies.
You're right, MRI (or nMRI) is nMR (Imaging). But the first poster said nMR and I wasn't feeling pedantic enough to contradict him. I really don't see how you'd use this at all if you weren't imaging.
In MRI you create an image by manipulating the relative phase of atomic nuclei with net magnetic moments. You measure the resulting interference for a bunch of different relative phases, then Fourier transform to get an image. It's interferometric imaging, except you're manipulating the phase instead of the sensor positions (as in radio interferometric imaging).
You're right, it does look similar to phase contrast CT. I'm not sure it's quite the same thing as they're doing here, but that's because the article on this technique isn't very clear.
That appears to be a link to a whiney Slashdotter posting his unfounded opinion.
"Apple screws developers more than users"
Most Apple developers seem to be quite happy. How exactly are they getting screwed?
It's already happened. But so what? I hate to tell you, but most people use their computers for surfing the web, Skype and maybe some e-mail.
I took mine on a trip to Europe last year instead of my notebook. It was slightly more awkward to do a few things but MUCH easier to carry. I wouldn't want to switch to an iPad exclusively, but for 90% of the people I know a tablet would probably be fine for their only personal computer.
I'm sure you can think of something to do with a B-52.
"You can type on an iPad- just not as easily."
A little bit of practice and you can get pretty damned fast. I wouldn't want to write a paper on it (yet), but I've found myself not bothering to open the notebook to answer most e-mail. I can probably do about half my keyboard typing speed on it... say 40 wpm.