Well, the PHYSICS clearly allow for it. We have extant examples of nanoscale sensors of all sorts. And since each rock is very small, just kicking off a few atoms would be enough to change it's course over a sufficiently long distance/time. For an interstellar trip, some of these rocks are going to travel for light-years before finally reaching the starship.
I think that any civilization capable of creating the linear accelerator millions of kilometers long, and packing sentience into molecular computers can probably solve the engineering problem of mass producing nanoscale pebbles with integrated guidance and maneuvering.
Actually, the red light problem is easily solvable. The slower you go, the less power the electric motors need. You could track via GPS how close you are to the next charging station, and automatically turn off things like the A/C if needed to make sure the bus gets to the next charge point.
The other reason for rocks is acceleration. Physical limits on how good your sail can be mean that the laser you use can only be so bright. This in turn limits the acceleration of your starship. Even though the starships I am proposing will never have human crew, the faster they reach the destination, the better. You don't want to wait for years just to get close to the speed of light. (I'm thinking 50%90% of the speed of light will be the target velocity you want to reach in order to make an interstellar journey)
If you are wondering, the 'crew' of the starship will be sentient beings running on molecular computers. They might be simulated versions of human beings, but would probably think in a manner quite different than humans. They will carry with them enough molecular tools to rapidly recreate the civilization that launched them at the destination star system.
The receiving and shooting coil is the same coil. Or, rather, a linear series of coils...the spacecraft would be incredible long and would be mostly just a series of superconducting electromagnets.
To prevent collisions, when you fire the pebble back the other direction you steer it just slightly off axis so that it won't hit the incoming pebble. You cancel out the tiny amount momentum change by sending the next pebble slightly off axis the other way.
The cannon is a massive accelerator in our solar system. It stays stationary either by firing an identical pebble the OTHER direction each time it fires, or by being anchored to a moon or other large planetary body. (granted, it would slowly push a moon out of it's orbit, but that would not be a problem for a while. Yes, it would fire the pebbles faster or more often as necessary according to a pre arranged plan so that the starship could reach it's destination.
You can't hold on to the pebbles. Every time you catch a pebble using electromagnets, the momentum of the pebble is added to the momentum of your starship. That's the way the engine works:P
One alternate idea is to use matter/anti matter pebbles when you are decelerating.
The reason for rocks is two fold : light and particle beams are subject to an inverse square law with distance. The spot size of the light or particle beam over a distance of light-years will quickly rise to the point that nearly all of the energy being beamed to your spaceship is wasted.
Basically, you need your desktop search application to look at the index file on the remote file server generated by an instance of the application running on the file server. Technically, incredibly simple but I don't know which application currently available is divided into front and back ends like that. Maybe open source...
Here's how a commercial, usable version of this technology would work. There would be a large tank (called a "holo tank" of course) made of glass, with a bigger rotating mirror. The mirror would probably be 30" diagonal or so. The tank would be evacuated of air so that the rotor could spin quickly without much noise or friction. Due to the internal vacuum, uh, tank the whole assembly would be quite large and heavy. A DLP projector with light from LEDs would project the image onto the rotating mirror. DLP mirrors are more than fast enough to refresh the image the 1000 times a second or so that this display would need.
The whole thing would need an awful lot of glass and fine optics inside it, more than anything from previous generations of technology. I suspect that a mass produced, mass market holo tank with a 30" mirror would cost several thousand dollars.
There would be two kinds of content it would display : one would be 3d content where the image just switches rapidly from left eye to right eye as the mirror spins. Essentially, you'd look at the tank from any angle, but would see the same thing in 3d. Films would be displayed this way.
The other would be true 3d, where if you walk around to the back you would see the back of the object in question. Doing it this way takes a LOT more computing power...but the probably is embarrassingly parallel, such that massively parallel CPUs and graphics cards would be well suited to generating the image.
I don't know if the technology will ever take off, again due to the aforementioned cost. Goggle displays that could create the ILLUSION of a holo tank in front of you would vastly cheaper to manufacture.
Question :
There's a nasty logarithm in the rocket equation. Basically, the lower the exit velocity of your propellant, the larger the % of the mass of your spaceship has to be dedicated to just fuel. Also, the higher the delta V you want, the bigger that percentage gets, to where you might need a fuel tank the size of the moon to get a pebble to Alpha Centauri.
Does a beam riding spacecraft where you ride on a beam of small smart rocks fired from a coilgun eliminate the logarithm? Basically, you'd have a coilgun out in space that would fire a series of tiny projectiles, weighing under a gram, with nanoscale guidance and maneuvering systems. They would hurtle through space until reaching your spacecraft, which would basically be a long coil-gun, and it would decelerate the projectile, storing the energy in capacitors, and then accelerate it the other direction.
Momentum is transferred, your spacecraft speeds up. For slowing down, you throw away most of your space ship and use the thrown away portion like a reflector.
The reasons for this exodus are straight out of an economics textbook. This is SUPPOSED to happen in a free world with free trade. Overall, this move is ADVANCING human civilization and making things just a bit better for the rest of humanity. Right now, the high tech industry in California is one of the most amazing industries the world has ever known. Among other things, those highly educated people who are returning to China and India are bringing knowledge and skills that will allow them to replicate some of the wonders of California in India and China. How is that a bad thing?
Sure, those Chinese and Indian companies will compete with the U.S. firms...but competition is a good thing for humanity as a whole.
Nothing. That drug I mentioned is in clinical trials today, and it seems to completely halt the disease progressing. It'll be 50-100 years or more before we can effectively replace missing neurons....long before that, people will no longer get Alzheimers because of drugs that block it.
Actually what they need is a drug that inhibits the formation of the plaques and Tau tangles that kill their entire brain a piece at a time. (the entire brain is dying in alzheimer's, but the memory systems are obviously the most fragile and the first to fail completely)
One time pad of course solve this problem. The bank would have one copy of a one time pad, and your card would have another. The bank's machine would send a "challenge" consisting of the next 16 bits off the bank's one time pad, and your chip would compare it to the next 16 unused bit's off the one time pad in the chip and then respond with about 16 bits following that on the one time pad. The total transaction would eat up 32 bits of the one time pad. The chip would not give any output at all unless interrogated with the correct part of the one time pad. After 10-20 failed attempts or so, the chip would permanently brick itself.
I leave it as an exercise to the reader to determine how much flash memory the chip would need so that it would not run out in in any reasonable length of time, with dozens to hundreds of banking transactions per day.
First of all, 3d gaming requires some serious tinkering. It's still a very immature, rare technology that works best with better displays than you can fit into a laptop. Right now, the DLP HDTVs that support 3d are the best available display with the least amount of ghosting.
Second, rendering 2 viewpoints puts far more load on the GPU than rendering just one. You need the fastest available single GPU nvidia graphics card in order to play recent games. It has to be single GPU because so far nvidia drivers don't support 3d and SLI at the same time. It has to be nvidia because only nvidia currently offers 3d drivers. There's a way to get 3d on an ATI card but it's limited.
Gaming on a laptop is already a bad bargain, 3d gaming is even worse.
Without all that said : I think 3d gaming is freakin' awesome. I even built myself a custom planar display a couple years ago in order to play games in 3d.
Umm, no. Actually, the equation is incredibly simple.
The COST (in special equipment, special knowledge, and time) of breaking the security measure has to exceed the typical gains a thief might get from the crime. The overall security scheme does not have to be bulletproof. After all, nearly no defense that a bank could devise would prevent a thief from obtaining money at gunpoint from the account holder. However, holding people at gunpoint involves an enormous inherent cost...
I just thought of a solution to the man in the middle attack.
In order to do a large transfer of funds, or anything else that a hacker could benefit from, you would be required to enter a code from the keyfob a SECOND time. That is, you would have to enter the code once to log into your online bank, and a SECOND time with a new code in order to move any serious amount of money. PER major transaction.
This would be vastly more difficult to do a man in the middle attack on.
Completely impossible if you use a One time Pad. If you use a secret key, and the display updates the code every 10 seconds, it is feasible that it would require the cracker to wait for several years or decades worth of data from the display in order to figure out what the secret key is.
Both ways, you might be able to glitch the secure chip by playing with temperature, voltage, or cutting into the chip and injecting current to the IC itself while it is still running. Or just read the bits off with a microscope.
It COULD be done...but it would be an arduous task that would require probably days of work, if not weeks with top of the line equipment in order to break into a single one of these cards.
And all the owner of the card has to do is notice it is missing, call the 1-800 number, and the card is revoked.
Security tokens store internally a crytographic key or a one time pad. It is mathematically impossible to find out what the secret key/OTP is on these devices from readouts on the display. You have to steal the device and read the bits using an electron microscope. Even if you could do that, it would be very difficult to create a cloned copy of the device and return it to the owner's possession in any length of time.
Thus, the inherent security is obvious : in order to break into an account protected by a keyfob, one absolutely HAS to steal the actual keyfob. That vastly limits the vulnerability : if the user still possesses the card, they KNOW they haven't been hacked to 99.9999999% certainty. Furthermore, only individuals who come in direct contact with the user have a chance to steal the card, and they cannot do so secretly - you could freely give your credit card to a waiter at a restraunt and have him use the keyfob with the secret code displayed, and know that the card could not have been skimmed.
And, of course, the moment the user of the card notices that it is missing, he can call the bank and cancel it and ask for a replacement, eliminating any further losses. If your account information had been compromised, you might not realize for month(s).
I will agree with you on "something you are" authentication. Even if you owned some kind of biometric reader and used it to log on to your bank, it is not any more secure than a password because a fingerprint or DNA sequence is a static piece of authentication. Well, ALMOST....
Theoretically, using technology not yet available, you could give the bank a sample of your genetic material and essentially have security whereby the bank asks your home DNA scanner "give me n->Z portion of the user's genome". This would only be a practical security measure if whole genome sequencing were still very expensive.
Ignoring the Big Brother/Police state implications for the moment : how well does this technology actually work? How accurate could the measurement of chin width/nose size be if you only have a single photo to make measurements from? With a large uncertainty in your data, I would imagine that there would be many collisions in the database.
It doesn't seem likely that a camera could be set up somewhere in the state that could recognize any North Carolina resident with a driver's license. More likely than not, there would be thousands of hits for each face that walked by the camera, even if the subject wasn't in the database.
The solar panel adds more bulk than a bigger battery would. It takes up a huge amount of real estate that could be occupied by another display. And, it really only helps you if you are planning on spending time reading outside - an impracticality in most parts of the United States, most of the time. Most of the year, outside is too hot, too cold, or infested with swarms of disease carrying mosquitoes. I go outside plenty of times when the weather is nice - but I'm active then. Sitting still and reading just makes you an easy target for the mosquitoes.
If you're going backpacking or to the third world, it's more convenient to just bring a dedicated solar panel with battery pack and adapters for your gadgets.
The only market for this device is eco-freaks with too much money and not enough sense. Which is usually self limiting - the people who earn the most money usually have enough intelligence and common sense to spot the flaws I just mentioned. The only reason that they might buy a device like this is to give the appearance of being 'green' to their friends.
I'm not referring to backups. If the backups are done off of the main database using known good code, and they are stored on media that is offline (whether that is hard drives that are physically off or tapes does not matter), then you can be reasonably certain that you have the data backed up, so long as nothing happens to the data storage facility and you included plenty of checksum data with each backup.
I'm saying that the main application code that runs the main database can't be guaranteed not to have a bug or flaw that could destroy data. Even if you could mathematically prove correctness for this large codebase, a hacker could possibly crack it and insert malicious code to destroy your data.
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Well, the PHYSICS clearly allow for it. We have extant examples of nanoscale sensors of all sorts. And since each rock is very small, just kicking off a few atoms would be enough to change it's course over a sufficiently long distance/time. For an interstellar trip, some of these rocks are going to travel for light-years before finally reaching the starship.
I think that any civilization capable of creating the linear accelerator millions of kilometers long, and packing sentience into molecular computers can probably solve the engineering problem of mass producing nanoscale pebbles with integrated guidance and maneuvering.
RTFA. There's a short section of overhead wires at each bus stop. The bus has arms that rise to touch the wires.
Conservation of momentum is an absolute law of physics. You cannot ever violate it. You said you were a rocket scientist?
Actually, the red light problem is easily solvable. The slower you go, the less power the electric motors need. You could track via GPS how close you are to the next charging station, and automatically turn off things like the A/C if needed to make sure the bus gets to the next charge point.
Pretty neat. There's tons of other uses for this technology. Among other things, ultra-capacitors are probably the way to go for non plug in hybrids.
The other reason for rocks is acceleration. Physical limits on how good your sail can be mean that the laser you use can only be so bright. This in turn limits the acceleration of your starship. Even though the starships I am proposing will never have human crew, the faster they reach the destination, the better. You don't want to wait for years just to get close to the speed of light. (I'm thinking 50%90% of the speed of light will be the target velocity you want to reach in order to make an interstellar journey)
If you are wondering, the 'crew' of the starship will be sentient beings running on molecular computers. They might be simulated versions of human beings, but would probably think in a manner quite different than humans. They will carry with them enough molecular tools to rapidly recreate the civilization that launched them at the destination star system.
The receiving and shooting coil is the same coil. Or, rather, a linear series of coils...the spacecraft would be incredible long and would be mostly just a series of superconducting electromagnets.
To prevent collisions, when you fire the pebble back the other direction you steer it just slightly off axis so that it won't hit the incoming pebble. You cancel out the tiny amount momentum change by sending the next pebble slightly off axis the other way.
The cannon is a massive accelerator in our solar system. It stays stationary either by firing an identical pebble the OTHER direction each time it fires, or by being anchored to a moon or other large planetary body. (granted, it would slowly push a moon out of it's orbit, but that would not be a problem for a while. Yes, it would fire the pebbles faster or more often as necessary according to a pre arranged plan so that the starship could reach it's destination.
You can't hold on to the pebbles. Every time you catch a pebble using electromagnets, the momentum of the pebble is added to the momentum of your starship. That's the way the engine works :P
One alternate idea is to use matter/anti matter pebbles when you are decelerating.
The reason for rocks is two fold : light and particle beams are subject to an inverse square law with distance. The spot size of the light or particle beam over a distance of light-years will quickly rise to the point that nearly all of the energy being beamed to your spaceship is wasted.
Basically, you need your desktop search application to look at the index file on the remote file server generated by an instance of the application running on the file server. Technically, incredibly simple but I don't know which application currently available is divided into front and back ends like that. Maybe open source...
Here's how a commercial, usable version of this technology would work. There would be a large tank (called a "holo tank" of course) made of glass, with a bigger rotating mirror. The mirror would probably be 30" diagonal or so. The tank would be evacuated of air so that the rotor could spin quickly without much noise or friction. Due to the internal vacuum, uh, tank the whole assembly would be quite large and heavy. A DLP projector with light from LEDs would project the image onto the rotating mirror. DLP mirrors are more than fast enough to refresh the image the 1000 times a second or so that this display would need.
The whole thing would need an awful lot of glass and fine optics inside it, more than anything from previous generations of technology. I suspect that a mass produced, mass market holo tank with a 30" mirror would cost several thousand dollars.
There would be two kinds of content it would display : one would be 3d content where the image just switches rapidly from left eye to right eye as the mirror spins. Essentially, you'd look at the tank from any angle, but would see the same thing in 3d. Films would be displayed this way.
The other would be true 3d, where if you walk around to the back you would see the back of the object in question. Doing it this way takes a LOT more computing power...but the probably is embarrassingly parallel, such that massively parallel CPUs and graphics cards would be well suited to generating the image.
I don't know if the technology will ever take off, again due to the aforementioned cost. Goggle displays that could create the ILLUSION of a holo tank in front of you would vastly cheaper to manufacture.
Question : There's a nasty logarithm in the rocket equation. Basically, the lower the exit velocity of your propellant, the larger the % of the mass of your spaceship has to be dedicated to just fuel. Also, the higher the delta V you want, the bigger that percentage gets, to where you might need a fuel tank the size of the moon to get a pebble to Alpha Centauri. Does a beam riding spacecraft where you ride on a beam of small smart rocks fired from a coilgun eliminate the logarithm? Basically, you'd have a coilgun out in space that would fire a series of tiny projectiles, weighing under a gram, with nanoscale guidance and maneuvering systems. They would hurtle through space until reaching your spacecraft, which would basically be a long coil-gun, and it would decelerate the projectile, storing the energy in capacitors, and then accelerate it the other direction. Momentum is transferred, your spacecraft speeds up. For slowing down, you throw away most of your space ship and use the thrown away portion like a reflector.
Imagine being an insurgent hiding in a cave once the Pentagon equips this robot with a bomb, or better yet, Sony batteries...
The reasons for this exodus are straight out of an economics textbook. This is SUPPOSED to happen in a free world with free trade. Overall, this move is ADVANCING human civilization and making things just a bit better for the rest of humanity. Right now, the high tech industry in California is one of the most amazing industries the world has ever known. Among other things, those highly educated people who are returning to China and India are bringing knowledge and skills that will allow them to replicate some of the wonders of California in India and China. How is that a bad thing?
Sure, those Chinese and Indian companies will compete with the U.S. firms...but competition is a good thing for humanity as a whole.
Nothing. That drug I mentioned is in clinical trials today, and it seems to completely halt the disease progressing. It'll be 50-100 years or more before we can effectively replace missing neurons....long before that, people will no longer get Alzheimers because of drugs that block it.
Actually what they need is a drug that inhibits the formation of the plaques and Tau tangles that kill their entire brain a piece at a time. (the entire brain is dying in alzheimer's, but the memory systems are obviously the most fragile and the first to fail completely)
One time pad of course solve this problem. The bank would have one copy of a one time pad, and your card would have another. The bank's machine would send a "challenge" consisting of the next 16 bits off the bank's one time pad, and your chip would compare it to the next 16 unused bit's off the one time pad in the chip and then respond with about 16 bits following that on the one time pad. The total transaction would eat up 32 bits of the one time pad. The chip would not give any output at all unless interrogated with the correct part of the one time pad. After 10-20 failed attempts or so, the chip would permanently brick itself.
I leave it as an exercise to the reader to determine how much flash memory the chip would need so that it would not run out in in any reasonable length of time, with dozens to hundreds of banking transactions per day.
Not if you're using Nvidia's crummy drivers...
This is pointless and stupid : here's why.
First of all, 3d gaming requires some serious tinkering. It's still a very immature, rare technology that works best with better displays than you can fit into a laptop. Right now, the DLP HDTVs that support 3d are the best available display with the least amount of ghosting.
Second, rendering 2 viewpoints puts far more load on the GPU than rendering just one. You need the fastest available single GPU nvidia graphics card in order to play recent games. It has to be single GPU because so far nvidia drivers don't support 3d and SLI at the same time. It has to be nvidia because only nvidia currently offers 3d drivers. There's a way to get 3d on an ATI card but it's limited.
Gaming on a laptop is already a bad bargain, 3d gaming is even worse.
Without all that said : I think 3d gaming is freakin' awesome. I even built myself a custom planar display a couple years ago in order to play games in 3d.
Umm, no. Actually, the equation is incredibly simple.
The COST (in special equipment, special knowledge, and time) of breaking the security measure has to exceed the typical gains a thief might get from the crime. The overall security scheme does not have to be bulletproof. After all, nearly no defense that a bank could devise would prevent a thief from obtaining money at gunpoint from the account holder. However, holding people at gunpoint involves an enormous inherent cost...
I just thought of a solution to the man in the middle attack.
In order to do a large transfer of funds, or anything else that a hacker could benefit from, you would be required to enter a code from the keyfob a SECOND time. That is, you would have to enter the code once to log into your online bank, and a SECOND time with a new code in order to move any serious amount of money. PER major transaction.
This would be vastly more difficult to do a man in the middle attack on.
Completely impossible if you use a One time Pad. If you use a secret key, and the display updates the code every 10 seconds, it is feasible that it would require the cracker to wait for several years or decades worth of data from the display in order to figure out what the secret key is.
Both ways, you might be able to glitch the secure chip by playing with temperature, voltage, or cutting into the chip and injecting current to the IC itself while it is still running. Or just read the bits off with a microscope.
It COULD be done...but it would be an arduous task that would require probably days of work, if not weeks with top of the line equipment in order to break into a single one of these cards.
And all the owner of the card has to do is notice it is missing, call the 1-800 number, and the card is revoked.
Wrong.
Security tokens store internally a crytographic key or a one time pad. It is mathematically impossible to find out what the secret key/OTP is on these devices from readouts on the display. You have to steal the device and read the bits using an electron microscope. Even if you could do that, it would be very difficult to create a cloned copy of the device and return it to the owner's possession in any length of time.
Thus, the inherent security is obvious : in order to break into an account protected by a keyfob, one absolutely HAS to steal the actual keyfob. That vastly limits the vulnerability : if the user still possesses the card, they KNOW they haven't been hacked to 99.9999999% certainty. Furthermore, only individuals who come in direct contact with the user have a chance to steal the card, and they cannot do so secretly - you could freely give your credit card to a waiter at a restraunt and have him use the keyfob with the secret code displayed, and know that the card could not have been skimmed.
And, of course, the moment the user of the card notices that it is missing, he can call the bank and cancel it and ask for a replacement, eliminating any further losses. If your account information had been compromised, you might not realize for month(s).
I will agree with you on "something you are" authentication. Even if you owned some kind of biometric reader and used it to log on to your bank, it is not any more secure than a password because a fingerprint or DNA sequence is a static piece of authentication. Well, ALMOST....
Theoretically, using technology not yet available, you could give the bank a sample of your genetic material and essentially have security whereby the bank asks your home DNA scanner "give me n->Z portion of the user's genome". This would only be a practical security measure if whole genome sequencing were still very expensive.
Ignoring the Big Brother/Police state implications for the moment : how well does this technology actually work? How accurate could the measurement of chin width/nose size be if you only have a single photo to make measurements from? With a large uncertainty in your data, I would imagine that there would be many collisions in the database.
It doesn't seem likely that a camera could be set up somewhere in the state that could recognize any North Carolina resident with a driver's license. More likely than not, there would be thousands of hits for each face that walked by the camera, even if the subject wasn't in the database.
The solar panel adds more bulk than a bigger battery would. It takes up a huge amount of real estate that could be occupied by another display. And, it really only helps you if you are planning on spending time reading outside - an impracticality in most parts of the United States, most of the time. Most of the year, outside is too hot, too cold, or infested with swarms of disease carrying mosquitoes. I go outside plenty of times when the weather is nice - but I'm active then. Sitting still and reading just makes you an easy target for the mosquitoes.
If you're going backpacking or to the third world, it's more convenient to just bring a dedicated solar panel with battery pack and adapters for your gadgets.
The only market for this device is eco-freaks with too much money and not enough sense. Which is usually self limiting - the people who earn the most money usually have enough intelligence and common sense to spot the flaws I just mentioned. The only reason that they might buy a device like this is to give the appearance of being 'green' to their friends.
I'm not referring to backups. If the backups are done off of the main database using known good code, and they are stored on media that is offline (whether that is hard drives that are physically off or tapes does not matter), then you can be reasonably certain that you have the data backed up, so long as nothing happens to the data storage facility and you included plenty of checksum data with each backup.
I'm saying that the main application code that runs the main database can't be guaranteed not to have a bug or flaw that could destroy data. Even if you could mathematically prove correctness for this large codebase, a hacker could possibly crack it and insert malicious code to destroy your data.