BH have a non-zero temperature, so they emit black body radiation. BB radiation emits at *all* wavelengths, regardless of the temperature, so including visible wavelengths. This is so regardless of the mass of the BH. At the right mass, a BH can emit mainly in the visible part of the spectrum, and so be very visible in all senses of the word.
I have provided a reference to the "reflected light" claim. Please go read it, or look for "Luminet Black Holes" in Google. Happy reading.
Hi, thanks for the reply. Your points are well taken but besides mine.
Why don't you read the book chapter I linked to and reply to the points it makes ? I find it very enlightening;)
I'm only a mathematician and computer scientist, but J.P. Luminet, the author of the chapter I linked to in the GP, is definitely a physicist and a specialist on BH as well as a great writer. In it he compares the light output of a number of bodies, including a perfectly black, matte sphere, a highly polished metallic sphere and BH when all 3 are illuminated by a light source close to the observer. A BH reflects more light at the observer than the other two, and hence is more visible.
BH actually reflect light. Not in the usual, mirror-like sense, but by gravitationally bending the light around it. Interesting, no?
A very cold, dark, matte sphere would be less visible than a BH, so the latter is not the darkest object one can think of.
So don't take it personnally, but I think you fall into the well-educated scientist who doesn't know everything about BH category. I know almost nothing but I've read Luminet's book.
1- They emit black body radiation at the Hawkings temperature due to quantum evaporation, which for a tiny black hole is very high. A black hole created by an accelerator, composed of the mass of a few particles would likely be extremely hot for a very short time, and so would emit gamma rays. Wikipedia has the calculation for a 1kg BH : the lifetime is approximately 10^{-16} seconds, and the energy output equivalent to the complete anihilation of the 1kg mass (you don't want to be around). Small black holes are *fierce*, however subatomic ones don't really matter. After all accelerators anihiliate particles all the time.
The above is the #1 reason BH potentially created by accelerators are not a concern.
2- Even very large BH are in fact directly visible. They reflect light better than a highly polished metallic sphere.
These two facts are direct illustrations that most people, including well-educated scientists, don't know the first thing about BH.
Does it? you mean apart from never losing the content of its memory, having a 100x better screen (colour, resolution and touchscreen), easier and faster input, ability to play video and music, Wifi, a usable browser and 1000x more memory (8GB vs 8MB), the iPod touch is totally much worse than a Palm III?
In certain jurisdictions, yes a signature is requested, sometime even with extra handwritten approval (such as "I have read and I approve") otherwise the contract is not binding.
Presumably the difference in distance would come from the fact most of the GRB radiation is, hmm, gamma ray? The visible portion of the spectrum constitute a negligible portion of the output.
According to the Fine Article, This "just a guy" not only is a psychology major, he has an OR (operations research) masters, which is basically applied math : optimisation, statistics, etc. This is just the kind of winning combination for this type of problems.
What AI program, pray? I was unaware we had an AI program ready to think for us, only asking for a few hexaflops here or there.
I think Sandia would probably like to run lattice QCD simulations. Those can chew through any amount of hexaflops you can throw at them. Otherwise we have the ever-demanding weather bureau for these elusive 15-day forecasts. It's not difficult to conjure up a problem that would take weeks to run on current hardware. Indeed neural simulations are a possibility, but not the only one.
Actually a baby has plenty of hard-wired and flexible structure already working fine doing something useful. I'll spare you most of the detais, but babies can breathe, eat, etc. They can barely see but they can hear, smell. they have a working memory, and they can communicate effectively, and not just by crying.
The brain tissue simulation had no particular structure. If they had been able to simulate say memory from neuron collections I would have been very impressed. This was just a simulation of a collection of simulated primitive neurons firing and inhibiting each other with no outcome. We don't know how to set up useful neuron structures.
Yes, quantum mechanics can be simulated, but very inefficiently. That thought requires quantum operations would be a major discovery. At the moment it's speculation at best.
No he didn't. He ran a simulation of a large bunch of neurons equivalent to a 300mm x 300mm area of flat neuronal tissue, which ran for a month or so. The simulation exhibited some lifelike patterns like alpha-waves, but apart from that, sorry, no thought or philosophy came out, and no real insight about brain structure came out. There is a nice video of the outcome.
He simulated a simple physiological model of a collection of neurons, but not a brain at work. In his own word he could have done the same work with a 1000 neurons simulation, but he wanted to do the large scale one to show it was possible.
He estimates we can maybe simulate a number of neurons similar to that in the brain in real-time from 2016 onwards (just barely though), however, as he writes "many essential details of the anatomy and dynamics of the mammalian nervous system would probably be still unknown."
At some point, lowering taxes to the point where hospitals, roads and schools are no longer supported also makes everyone poorer.
In the US you are well aware that median life expectancy is lower than in many other Western countries, and that standards of primary and secondary education are also lower than they should be. Perhaps this is a consequence that the US have such a high proportion of crime and people in prison, also compared to other Western countries. These are all facts as well.
So I'm not talking about extremes of socialism or free market. Somewhere in the middle there must be a better optimum than either, perhaps in nothern Europe or Australia, or even, God forbid, in Canada.
Switching OS is no small matters. I'm used to Unix/Linux, I have been using some version of it since 1986 or so. To me switching to Windows is a pain in the butt because the console doesn't work well. Have you tried copy/paste to the default console, or using search in command-line history? To me it's Windows that doesn't do the basics right. Who cares about drag-and-drop, that's a silly crutch;-)
Similarly, when I got a Mac under OS/X I got very frustrated by the extremely peculiar UI. Some things are indeed very easy but others very hard. Only after I found a replacement for Terminal.app, added a ton of standard Unix applications like compilers, Emacs, LaTeX and so forth, and found out how to start applications from the command line did I start being more productive. Now I feel I know OS/X quite well (including using DnD, exposé, spotlight, etc), but that was (a) not so easy and (b) long. However I feel this was very worthwhile in the end. Indeed I find DnD sometimes quite useful after all, but this is not my only trick.
The bottom line is you can't expect Linux to reproduce your Windows experience. You have to meet somewhere in the middle. In the process you learn something that might help you make your life easier.
With your Windows-only experience (or perhaps OS/X + Windows, you do mention and iBook), you are stuck in a local optimum of productivity. It takes pains to leave it but there maybe a more global optimum for you in the OS space.
I take your point about supported hardware though. In general unsupported hardware is due to the manufacturer's unwillingness to disclose driver issues, but not always. In your case the SB should have worked.
No, techies and trekies tend to focus on the problems they think can be solved through the use of science and technology, and call the potential solutions smart, even though they may not necessarily work in the real world.
They also think that they are being quite successful thanks to their wit and they can't see why everybody cannot do the same, and consequently wonder why they should pay for social security. Hence, they lean to the right. Techies are not very good with empathy, usually.
However, when the whole planet catches on and starts threatening their job, they call for government intervention.
The power cable for a laptop is usually the only one dropping all the way down to the floor, likely to trip you and damage the cord and the laptop. I've never seen someone tripped by a mouse cable.
Mice, USB, FW, video and whatnot cables stay on the desktop. I don't know about you but I don't usually walk on my desk.
They are in a weaker position, in the sense that Vista is not good and not liked even by those who usually don't care, that there are newer and cheaper devices out there like Asus Eeepc or the XO that ship without Windows because the license is too expensive for these devices. It is expected that these new machine improve the market share of Linux significantly. The market response to the Eeepc in particular has been remarkable and does put credence that a pre-installed Linux is viable.
Then Apple has made a huge comeback, taking the limelight in the OS department, Xbox 360 is taking a beating wrt to the Wii, and OpenOffice is seriously threatening their core business. Moreover Microsoft has no reply to these new moves: they have waved empty patent threats, they are under scrutiny for any monopoly abuse, the EU is fining them left, right and center at every wrong move.
Finally Google is seen to be the tomorrow company, not Microsoft. This means new recruits are no longer top-notch like they used to be.
Microsoft is assailed on all fronts, and they are internally struggling at least. They won't go away, but hopefully in a few years we will have a kinder, gentler Microsoft to contend with. Maybe they can then put out nice products, like Office 2008 for the Mac for example.
There is a large gap between not letting DTrace trace anything about iTunes and allowing it to trace everything in the application. Perhaps Apple could have been a little more subtle about iTunes traces? At least they would have bought some time.
Actually, the Apple OpenGL port to OS/X is relatively slow, at least for games. The reason is that Apple is not interested in the latest-and-greatest OpenGL features aimed at games put out by the likes of NVidia and ATI/AMD. Apple provide their own drivers for the ATI and NVidia hardware they sell. In contrast, under Linux, these vendors provide the driver, and they have incentives to one-up each other.
In general, Apple is not interested in games and so provides a kind of minimum-service in this area.
The supply of F/OSS developers is limited, the revolution is happening but not overnight. Think of F/OSS as an enormous entity that puts forth the likes of the Linux & BSD kernels, the development tools, and all the little and great applications including the best GUI toolkits. No time for trifling matters there.
No clone of Photoshop, Autocad, Matlab, Mathematica and whatnot that is as good or better? Cry me a river. Some years ago people complained that there wasn't an OSS clone of bloody MS-Office that wasn't as good or better. Now look, we have OO.org, which gives it a run for its money, and multi-platform to boot. We know MS is shaking in its boots.
Adobe is next. I already prefer Inkscape to Illustrator. Wait another few years, we have the time.
Some software will be proprietary for a long time I think. Most games are short-lived and currently require much more than programming skills. However I've noticed the quality of OSS games improving vastly in the last few years, not least due to the practice of Id to Free its old engines.
At the moment it's possible to run F/OSS for most tasks. Personally I sometime run non-Free software to verify that I don't really to do this.
Slashdot Mirror
Hello everyone,
BH have a non-zero temperature, so they emit black body radiation. BB radiation emits at *all* wavelengths, regardless of the temperature, so including visible wavelengths. This is so regardless of the mass of the BH. At the right mass, a BH can emit mainly in the visible part of the spectrum, and so be very visible in all senses of the word.
I have provided a reference to the "reflected light" claim. Please go read it, or look for "Luminet Black Holes" in Google. Happy reading.
Hi, thanks for the reply. Your points are well taken but besides mine.
;)
Why don't you read the book chapter I linked to and reply to the points it makes ? I find it very enlightening
I'm only a mathematician and computer scientist, but J.P. Luminet, the author of the chapter I linked to in the GP, is definitely a physicist and a specialist on BH as well as a great writer. In it he compares the light output of a number of bodies, including a perfectly black, matte sphere, a highly polished metallic sphere and BH when all 3 are illuminated by a light source close to the observer. A BH reflects more light at the observer than the other two, and hence is more visible.
BH actually reflect light. Not in the usual, mirror-like sense, but by gravitationally bending the light around it. Interesting, no?
A very cold, dark, matte sphere would be less visible than a BH, so the latter is not the darkest object one can think of.
So don't take it personnally, but I think you fall into the well-educated scientist who doesn't know everything about BH category. I know almost nothing but I've read Luminet's book.
Cheers.
Black holes are not invisible on two accounts.
1- They emit black body radiation at the Hawkings temperature due to quantum evaporation, which for a tiny black hole is very high. A black hole created by an accelerator, composed of the mass of a few particles would likely be extremely hot for a very short time, and so would emit gamma rays. Wikipedia has the calculation for a 1kg BH : the lifetime is approximately 10^{-16} seconds, and the energy output equivalent to the complete anihilation of the 1kg mass (you don't want to be around). Small black holes are *fierce*, however subatomic ones don't really matter. After all accelerators anihiliate particles all the time.
The above is the #1 reason BH potentially created by accelerators are not a concern.
2- Even very large BH are in fact directly visible. They reflect light better than a highly polished metallic sphere.
These two facts are direct illustrations that most people, including well-educated scientists, don't know the first thing about BH.
When you buy a new PC you still pay the MS tax regardless of whether you run Linux or Windows.
In some European countries, a sale is not a contract, nor is an EULA.
Does it? you mean apart from never losing the content of its memory, having a 100x better screen (colour, resolution and touchscreen), easier and faster input, ability to play video and music, Wifi, a usable browser and 1000x more memory (8GB vs 8MB), the iPod touch is totally much worse than a Palm III?
In certain jurisdictions, yes a signature is requested, sometime even with extra handwritten approval (such as "I have read and I approve") otherwise the contract is not binding.
Presumably the difference in distance would come from the fact most of the GRB radiation is, hmm, gamma ray? The visible portion of the spectrum constitute a negligible portion of the output.
Well, where would you look for drm-free music in the first place? maybe you can find requiem there ?
According to the Fine Article, This "just a guy" not only is a psychology major, he has an OR (operations research) masters, which is basically applied math : optimisation, statistics, etc. This is just the kind of winning combination for this type of problems.
What AI program, pray? I was unaware we had an AI program ready to think for us, only asking for a few hexaflops here or there.
I think Sandia would probably like to run lattice QCD simulations. Those can chew through any amount of hexaflops you can throw at them. Otherwise we have the ever-demanding weather bureau for these elusive 15-day forecasts. It's not difficult to conjure up a problem that would take weeks to run on current hardware. Indeed neural simulations are a possibility, but not the only one.
Are you sure ?
According to this link, personal taxes are very low in the US. Corporate taxes are somewhat high though.
Actually a baby has plenty of hard-wired and flexible structure already working fine doing something useful. I'll spare you most of the detais, but babies can breathe, eat, etc. They can barely see but they can hear, smell. they have a working memory, and they can communicate effectively, and not just by crying.
The brain tissue simulation had no particular structure. If they had been able to simulate say memory from neuron collections I would have been very impressed. This was just a simulation of a collection of simulated primitive neurons firing and inhibiting each other with no outcome. We don't know how to set up useful neuron structures.
Yes, quantum mechanics can be simulated, but very inefficiently. That thought requires quantum operations would be a major discovery. At the moment it's speculation at best.
No he didn't. He ran a simulation of a large bunch of neurons equivalent to a 300mm x 300mm area of flat neuronal tissue, which ran for a month or so. The simulation exhibited some lifelike patterns like alpha-waves, but apart from that, sorry, no thought or philosophy came out, and no real insight about brain structure came out. There is a nice video of the outcome.
He simulated a simple physiological model of a collection of neurons, but not a brain at work. In his own word he could have done the same work with a 1000 neurons simulation, but he wanted to do the large scale one to show it was possible.
He estimates we can maybe simulate a number of neurons similar to that in the brain in real-time from 2016 onwards (just barely though), however, as he writes "many essential details of the anatomy and dynamics of the mammalian nervous system would probably be still unknown."
At some point, lowering taxes to the point where hospitals, roads and schools are no longer supported also makes everyone poorer.
In the US you are well aware that median life expectancy is lower than in many other Western countries, and that standards of primary and secondary education are also lower than they should be. Perhaps this is a consequence that the US have such a high proportion of crime and people in prison, also compared to other Western countries. These are all facts as well.
So I'm not talking about extremes of socialism or free market. Somewhere in the middle there must be a better optimum than either, perhaps in nothern Europe or Australia, or even, God forbid, in Canada.
Switching OS is no small matters. I'm used to Unix/Linux, I have been using some version of it since 1986 or so. To me switching to Windows is a pain in the butt because the console doesn't work well. Have you tried copy/paste to the default console, or using search in command-line history? To me it's Windows that doesn't do the basics right. Who cares about drag-and-drop, that's a silly crutch ;-)
Similarly, when I got a Mac under OS/X I got very frustrated by the extremely peculiar UI. Some things are indeed very easy but others very hard. Only after I found a replacement for Terminal.app, added a ton of standard Unix applications like compilers, Emacs, LaTeX and so forth, and found out how to start applications from the command line did I start being more productive. Now I feel I know OS/X quite well (including using DnD, exposé, spotlight, etc), but that was (a) not so easy and (b) long. However I feel this was very worthwhile in the end. Indeed I find DnD sometimes quite useful after all, but this is not my only trick.
The bottom line is you can't expect Linux to reproduce your Windows experience. You have to meet somewhere in the middle. In the process you learn something that might help you make your life easier.
With your Windows-only experience (or perhaps OS/X + Windows, you do mention and iBook), you are stuck in a local optimum of productivity. It takes pains to leave it but there maybe a more global optimum for you in the OS space.
I take your point about supported hardware though. In general unsupported hardware is due to the manufacturer's unwillingness to disclose driver issues, but not always. In your case the SB should have worked.
No, techies and trekies tend to focus on the problems they think can be solved through the use of science and technology, and call the potential solutions smart, even though they may not necessarily work in the real world.
They also think that they are being quite successful thanks to their wit and they can't see why everybody cannot do the same, and consequently wonder why they should pay for social security. Hence, they lean to the right. Techies are not very good with empathy, usually.
However, when the whole planet catches on and starts threatening their job, they call for government intervention.
The power cable for a laptop is usually the only one dropping all the way down to the floor, likely to trip you and damage the cord and the laptop. I've never seen someone tripped by a mouse cable.
Mice, USB, FW, video and whatnot cables stay on the desktop. I don't know about you but I don't usually walk on my desk.
They are in a weaker position, in the sense that Vista is not good and not liked even by those who usually don't care, that there are newer and cheaper devices out there like Asus Eeepc or the XO that ship without Windows because the license is too expensive for these devices. It is expected that these new machine improve the market share of Linux significantly. The market response to the Eeepc in particular has been remarkable and does put credence that a pre-installed Linux is viable.
Then Apple has made a huge comeback, taking the limelight in the OS department, Xbox 360 is taking a beating wrt to the Wii, and OpenOffice is seriously threatening their core business. Moreover Microsoft has no reply to these new moves: they have waved empty patent threats, they are under scrutiny for any monopoly abuse, the EU is fining them left, right and center at every wrong move.
Finally Google is seen to be the tomorrow company, not Microsoft. This means new recruits are no longer top-notch like they used to be.
Microsoft is assailed on all fronts, and they are internally struggling at least. They won't go away, but hopefully in a few years we will have a kinder, gentler Microsoft to contend with. Maybe they can then put out nice products, like Office 2008 for the Mac for example.
There is a large gap between not letting DTrace trace anything about iTunes and allowing it to trace everything in the application. Perhaps Apple could have been a little more subtle about iTunes traces? At least they would have bought some time.
Actually, the Apple OpenGL port to OS/X is relatively slow, at least for games. The reason is that Apple is not interested in the latest-and-greatest OpenGL features aimed at games put out by the likes of NVidia and ATI/AMD. Apple provide their own drivers for the ATI and NVidia hardware they sell. In contrast, under Linux, these vendors provide the driver, and they have incentives to one-up each other.
In general, Apple is not interested in games and so provides a kind of minimum-service in this area.
Not with an MSDN subscription I would wager, but otherwise yes, for a production site.
The supply of F/OSS developers is limited, the revolution is happening but not overnight. Think of F/OSS as an enormous entity that puts forth the likes of the Linux & BSD kernels, the development tools, and all the little and great applications including the best GUI toolkits. No time for trifling matters there.
No clone of Photoshop, Autocad, Matlab, Mathematica and whatnot that is as good or better? Cry me a river. Some years ago people complained that there wasn't an OSS clone of bloody MS-Office that wasn't as good or better. Now look, we have OO.org, which gives it a run for its money, and multi-platform to boot. We know MS is shaking in its boots.
Adobe is next. I already prefer Inkscape to Illustrator. Wait another few years, we have the time.
Some software will be proprietary for a long time I think. Most games are short-lived and currently require much more than programming skills. However I've noticed the quality of OSS games improving vastly in the last few years, not least due to the practice of Id to Free its old engines.
At the moment it's possible to run F/OSS for most tasks. Personally I sometime run non-Free software to verify that I don't really to do this.
Oh yes, mental illness is a perfectly valid excuse for just about anything, up to and including murder.