For this type of atomic X-ray laser I think the pump needs to have a higher photon energy that the lasing output. It is very much like a conventional laser except that the transitions occur at higher energies. If this is the experiment I am thinking of it was done a while ago but probably just published. Its a very nice demonstration.
A lot of aircraft GPS receivers are quite old. It can cost 10-20K$ to put a certified receiver in a light aircraft, so pilots will keep their existing equipment as long as possible. Changing the requirements on interference resistance might require very expensive re-certifications of these receivers.
If technologically advanced civilizations only exist on a small fraction of those worlds, me may just not have run into evidence of one yet: the galaxy is large even at even at the speed of light.
If technologically advanced civilizations are common, maybe they have watched and learned by experience that attracting attention is a *BAD IDEA*. There is a school of thought that says that the first thing you should do when you detect an alien intelligence is to try to exterminate it.
BTW: don't forget that there are also about 10^11 GALAXIES presumably each with on the order of 10^11 planets............ 10^22 is a BIG number.
But Why?????? If a commercial blasts at me, I get annoyed while looking at an add for their product. Why on earth do they think that this helps sales? I remember some adds from 30 years ago that irritated me so much that I still won't buy their product.
"If you told the Wright brothers that we'd be walking on the moon in 70 years they would have told you you're nuts. They wouldn't have believed it."
But if you told the Apollo astronauts that 40 years later we wouldn't be able to go back to the moon or if you told the Mercury astronauts that 50 years later the US would no longer be able to put a man in orbit, they would also think you were nuts.
Progress only happens because we do things, not just because time passes.
If you are in the US, the cost of the data is minimal. It really would be adding injury to insult though if you were being charged roaming rates for the stolen data when you out of the country.
That is often true, but so far we haven't seen terrorist nukes despite everyone knowing that its possible. One could argue that this is because bomb grade material is difficult to produce, knowledge of how to efficiently refine U235 is also kept protected. I don't have access to classified bomb-making information, but it wouldn't surprise me that there are relatively straightforward was to obtain bomb-grade fissionable materials.
I very rarely in favor of restricting information, but I think there are some lines of research that should be classified.
The US has a pretty low population density relative to those countries. It makes it difficult for rail to compete in cost and travel time with airliner service.
"checkpoint my ass" is where I'm afraid TSA security will go next..........
Seriously though, I don't think this is a power grab. More likely its just bureaucracy gone mad. TSA will be blamed if there are ANY terrorist incidents on aircraft so they have an incentive to do everything they can think of. In addition, the more money they spend, the larger their bureaucracy grows, and the more important its members feel, so by Parkinson's law they will tend to grow.
Scientist: Here are the assumptions in the models we used, and here are the sensitivities of the outputs to these assumptions and the statistical variations depending on the numerical seeds.
At this point, about 1% of the way through the paper, the Denier, Skeptic and Warmist all stop listening and want to know which cities will be flooded, and get unhappy if the answer doesn't match what they were given by the last scientist they talked to.
The climate is a fantastically complex system.There has been a lot of progress in climate modeling, but it isn't like predicting where a cannon ball will land if you know the starting trajectory.
Yes, I remember a flywheel regenerative braking test on new york subways done in the late 70's. I don't know why it wasn't adopted back then. Like many of the "new" energy ideas floating around now, it is a re-do of ideas from the previous "energy crisis"
I wonder why CBS was so clueless? It was FREE ADVERTISING! Its not in a competing market . Everyone who gets this fun app, or shows it to their friends is reminding everyone of the Star Trek series and movies. Some (small, but not zero) number of those people will go home and rent or stream one of the shows.
It was a really fun app - and impressive for just how much the sensors on a modern phone can do.
My job involves half a dozen international trips each year. If I don't make the trips, I need to find a new job. Oh wait - all the jobs in my chosen field (where I have decades of experience) require a lot of travel.
For some people, not flying really isn't a practical option.
I wonder how many large industrial plants assume that the power grid is 60Hz? At SLAC the accelerator is run synchronized to the 60Hz grid - I'd need to think (for quite a long time) to figure out how much frequency variation we can tolerate.
There is an enormous investment in old equipment attached to the power grid - most of it will do just fine, but it would not be easy to know in advance what might break.
You could define a standard for "minimum" speed. Say bottom 10th percentile speed for connected devices in their "service" range. The government could monitor this directly, or much better, could provide an app that people could (voluntarily) load onto their phones that would occasionally measure the bandwidth. If it providers bandwidth maps of the area I bet a lot of people would be happy to use it.
Its not perfect, but it is much better than the present system where speeds are essentially a guaranteed MAXIMUM, with absolutely no promise of what performance you will see. Sort of like saying that your care will get "up to 100 mpg" (though that will only be reached if it is in idle rolling down a steep hill).
There may be externalities that make it worth the government covering part of the cost. In this case it would give China influence in the countries with the rail lines, and might encourage more countries to purchase Chinese rail equipment.
Even within a country an improved transportation system can boost the economy in some areas and provide benefits to people in addition to those who directly use the service.
Another example would be if the rail system were being constructed by workers who would otherwise be unemployed and receiving government support. In that case the reduced cost of support would need to be factored into the calculation.
Lets see, disk space is about $50/TB, If I keep 3 backups (which I do, 1 offsite), that's $150/TB. I probably spend 2 hours / year dealing with backup issues (its mostly automated).
So, I'd pay say $300/year for a TB of storage with a $1M data loss guarantee. (that of course includes the network bandwidth to get at my data - say 10GB/day typical).
I doubt any companies will want my business at that rate.
I have a bonanza - also a small aircraft. When I take photos from the plane (using a digital SLR - Nikon D70 at the time), I could see the nav needles twitch.
Airliners have different avionics, etc, but it at least shows that it is possible.
Also - there may be a difference between 10 operating cell phones in the cabin, and 350. The RF power from the phones and other devices would sum, and might decrease the available signal to noise for the aircraft nav system.
The great majority of the time airplanes are operated within the federal aviation regulations. For cars, a significant fraction (probably a majority) of drivers regularly operate outside of the law (speeding). This system would in principal make it possible to completely enforce ALL speeding laws - is that what people really want?
The other difference is that airplanes fly to airports - their location doesn't give a lot of information about what the pilot is doing. Cars tend to drive to much more specific locations. Should the fact that you parked in your mistress's driveway for 2 hours over lunch be something the police can make publicly available? I've seen several cases where police have revealed information about affairs that suspects (NOT CONVICTED) were having.
Will police cars have the same trackers and is the data available?
AC transformers don't change the frequency. You would end up with few x 100THz power - eg. light. Basically the same as using a fiber to move the sunlight somewhere else - you still need to convert to DC for most applications.
Unfortunately unless you combine in a nonlinear device, the beat just has the original frequency components. If you were to combine the 2 signals in a linear circuit and then low pass filter, you wouldn't see anything. A nonlinear combination would produce a low frequency signal - this technique is called "mixing" and is very widely used in radio systems. The mixer that does the nonlinear combination is typically constructed from a set of diodes - so you wind up back with the original problem.
I've bought some 300Ghz diodes from Virginia Diodes. Worked great, but $7K each as I remember......
Here they need more like 100 THz. Might be possible with some sort of nonlinear optical material, but the fields are probably much too low.
Even if this whole scheme does work, its not clear it is any better than a conventional solar cell - they are quite efficient for narrow-band radiation right above their bandgap. You can stack different band-gap solar cells to get a quite efficient stack, but it doesn't make economic sense - sunlight is free, its the solar cells that cost money......
What are they using to rectify the signal to convert to DC? The antenna is neat - but not at all surprising, its size should just scale with wavelength. You could make a 125nm long antenna that would resonate with visible light (well withing the resolution of existing lithography). The problem is how to convert the 100THz signal you get to a DC signal. You need a fantastically fast diode.
If they have managed this, that would be an impressive achievement. The fastest diodes I am aware of are around 1THz, but its well outside my field and there might be something faster out there
BTW: the efficiency isn't all the impressive. For single frequency light, conventional solar cells can be quite efficient (~80%???), but they don't do will with broad thermal light (like sunlight). The photons that are less than a band-gap don't do anything, and the ones above a bandgap waste any excess energy.
How wealthy and how small is this "wealthy ruling class". You are talking more than people who made a killing on stock options during the internet boom? I wouldn't be at all surprised to find that a few ultra-wealthy ex-nerds post on slashdot, though possibly anonymously.
Slashdot Mirror
For this type of atomic X-ray laser I think the pump needs to have a higher photon energy that the lasing output. It is very much like a conventional laser except that the transitions occur at higher energies. If this is the experiment I am thinking of it was done a while ago but probably just published. Its a very nice demonstration.
Joe Frisch
SLAC / LCLS
A lot of aircraft GPS receivers are quite old. It can cost 10-20K$ to put a certified receiver in a light aircraft, so pilots will keep their existing equipment as long as possible. Changing the requirements on interference resistance might require very expensive re-certifications of these receivers.
If technologically advanced civilizations only exist on a small fraction of those worlds, me may just not have run into evidence of one yet: the galaxy is large even at even at the speed of light.
If technologically advanced civilizations are common, maybe they have watched and learned by experience that attracting attention is a *BAD IDEA*. There is a school of thought that says that the first thing you should do when you detect an alien intelligence is to try to exterminate it.
BTW: don't forget that there are also about 10^11 GALAXIES presumably each with on the order of 10^11 planets............ 10^22 is a BIG number.
But Why??????
If a commercial blasts at me, I get annoyed while looking at an add for their product. Why on earth do they think that this helps sales? I remember some adds from 30 years ago that irritated me so much that I still won't buy their product.
"If you told the Wright brothers that we'd be walking on the moon in 70 years they would have told you you're nuts. They wouldn't have believed it."
But if you told the Apollo astronauts that 40 years later we wouldn't be able to go back to the moon or if you told the Mercury astronauts that 50 years later the US would no longer be able to put a man in orbit, they would also think you were nuts.
Progress only happens because we do things, not just because time passes.
If you are in the US, the cost of the data is minimal. It really would be adding injury to insult though if you were being charged roaming rates for the stolen data when you out of the country.
That is often true, but so far we haven't seen terrorist nukes despite everyone knowing that its possible. One could argue that this is because bomb grade material is difficult to produce, knowledge of how to efficiently refine U235 is also kept protected. I don't have access to classified bomb-making information, but it wouldn't surprise me that there are relatively straightforward was to obtain bomb-grade fissionable materials.
I very rarely in favor of restricting information, but I think there are some lines of research that should be classified.
The US has a pretty low population density relative to those countries. It makes it difficult for rail to compete in cost and travel time with airliner service.
"checkpoint my ass" is where I'm afraid TSA security will go next..........
Seriously though, I don't think this is a power grab. More likely its just bureaucracy gone mad. TSA will be blamed if there are ANY terrorist incidents on aircraft so they have an incentive to do everything they can think of. In addition, the more money they spend, the larger their bureaucracy grows, and the more important its members feel, so by Parkinson's law they will tend to grow.
Scientist: Here are the assumptions in the models we used, and here are the sensitivities of the outputs to these assumptions and the statistical variations depending on the numerical seeds.
At this point, about 1% of the way through the paper, the Denier, Skeptic and Warmist all stop listening and want to know which cities will be flooded, and get unhappy if the answer doesn't match what they were given by the last scientist they talked to.
The climate is a fantastically complex system.There has been a lot of progress in climate modeling, but it isn't like predicting where a cannon ball will land if you know the starting trajectory.
SLAC has a visitor center and public tours. Some of the scientists / engineers there are also happy to show visitors around.
--- Joe Frisch
Yes, I remember a flywheel regenerative braking test on new york subways done in the late 70's. I don't know why it wasn't adopted back then. Like many of the "new" energy ideas floating around now, it is a re-do of ideas from the previous "energy crisis"
I wonder why CBS was so clueless? It was FREE ADVERTISING! Its not in a competing market . Everyone who gets this fun app, or shows it to their friends is reminding everyone of the Star Trek series and movies. Some (small, but not zero) number of those people will go home and rent or stream one of the shows.
It was a really fun app - and impressive for just how much the sensors on a modern phone can do.
My job involves half a dozen international trips each year. If I don't make the trips, I need to find a new job. Oh wait - all the jobs in my chosen field (where I have decades of experience) require a lot of travel.
For some people, not flying really isn't a practical option.
I wonder how many large industrial plants assume that the power grid is 60Hz? At SLAC the accelerator is run synchronized to the 60Hz grid - I'd need to think (for quite a long time) to figure out how much frequency variation we can tolerate.
There is an enormous investment in old equipment attached to the power grid - most of it will do just fine, but it would not be easy to know in advance what might break.
You could define a standard for "minimum" speed. Say bottom 10th percentile speed for connected devices in their "service" range. The government could monitor this directly, or much better, could provide an app that people could (voluntarily) load onto their phones that would occasionally measure the bandwidth. If it providers bandwidth maps of the area I bet a lot of people would be happy to use it.
Its not perfect, but it is much better than the present system where speeds are essentially a guaranteed MAXIMUM, with absolutely no promise of what performance you will see. Sort of like saying that your care will get "up to 100 mpg" (though that will only be reached if it is in idle rolling down a steep hill).
There may be externalities that make it worth the government covering part of the cost. In this case it would give China influence in the countries with the rail lines, and might encourage more countries to purchase Chinese rail equipment.
Even within a country an improved transportation system can boost the economy in some areas and provide benefits to people in addition to those who directly use the service.
Another example would be if the rail system were being constructed by workers who would otherwise be unemployed and receiving government support. In that case the reduced cost of support would need to be factored into the calculation.
Lets see, disk space is about $50/TB, If I keep 3 backups (which I do, 1 offsite), that's $150/TB. I probably spend 2 hours / year dealing with backup issues (its mostly automated).
So, I'd pay say $300/year for a TB of storage with a $1M data loss guarantee. (that of course includes the network bandwidth to get at my data - say 10GB/day typical).
I doubt any companies will want my business at that rate.
I have a bonanza - also a small aircraft. When I take photos from the plane (using a digital SLR - Nikon D70 at the time), I could see the nav needles twitch.
Airliners have different avionics, etc, but it at least shows that it is possible.
Also - there may be a difference between 10 operating cell phones in the cabin, and 350. The RF power from the phones and other devices would sum, and might decrease the available signal to noise for the aircraft nav system.
The great majority of the time airplanes are operated within the federal aviation regulations. For cars, a significant fraction (probably a majority) of drivers regularly operate outside of the law (speeding). This system would in principal make it possible to completely enforce ALL speeding laws - is that what people really want?
The other difference is that airplanes fly to airports - their location doesn't give a lot of information about what the pilot is doing. Cars tend to drive to much more specific locations. Should the fact that you parked in your mistress's driveway for 2 hours over lunch be something the police can make publicly available? I've seen several cases where police have revealed information about affairs that suspects (NOT CONVICTED) were having.
Will police cars have the same trackers and is the data available?
AC transformers don't change the frequency. You would end up with few x 100THz power - eg. light. Basically the same as using a fiber to move the sunlight somewhere else - you still need to convert to DC for most applications.
Unfortunately unless you combine in a nonlinear device, the beat just has the original frequency components. If you were to combine the 2 signals in a linear circuit and then low pass filter, you wouldn't see anything. A nonlinear combination would produce a low frequency signal - this technique is called "mixing" and is very widely used in radio systems. The mixer that does the nonlinear combination is typically constructed from a set of diodes - so you wind up back with the original problem.
I've bought some 300Ghz diodes from Virginia Diodes. Worked great, but $7K each as I remember......
Here they need more like 100 THz. Might be possible with some sort of nonlinear optical material, but the fields are probably much too low.
Even if this whole scheme does work, its not clear it is any better than a conventional solar cell - they are quite efficient for narrow-band radiation right above their bandgap. You can stack different band-gap solar cells to get a quite efficient stack, but it doesn't make economic sense - sunlight is free, its the solar cells that cost money......
What are they using to rectify the signal to convert to DC? The antenna is neat - but not at all surprising, its size should just scale with wavelength. You could make a 125nm long antenna that would resonate with visible light (well withing the resolution of existing lithography). The problem is how to convert the 100THz signal you get to a DC signal. You need a fantastically fast diode.
If they have managed this, that would be an impressive achievement. The fastest diodes I am aware of are around 1THz, but its well outside my field and there might be something faster out there
BTW: the efficiency isn't all the impressive. For single frequency light, conventional solar cells can be quite efficient (~80%???), but they don't do will with broad thermal light (like sunlight). The photons that are less than a band-gap don't do anything, and the ones above a bandgap waste any excess energy.
How wealthy and how small is this "wealthy ruling class". You are talking more than people who made a killing on stock options during the internet boom? I wouldn't be at all surprised to find that a few ultra-wealthy ex-nerds post on slashdot, though possibly anonymously.