There are two types of planets: Earth-like and Jupiter-like. All planets are some linear combination of these. If we propose a unit vector E to be (1,0) and a unit vector J to be (0,1) any planet can be classified using a linear combination of these two vectors.
Oh, and a planet's location in this orthogonal planet space does not need to be a unit vector. Venus would be something like 0.98E + 0J. Saturn would be something like 0E + 0.6J. Mercury would be something like 0.05E + 0J. I am unsure of what a 0.5E + 0.5J planet would look like. It would probably be a good place to look for short stocky people who like thick fog.
The T2K http://jnusrv01.kek.jp/public/t2k/ experiment is basically a neutrino beam generator. A standard particle accelerator fires its beam into a target, generating a roughly collimated beam of neutrinos via a nuclear reaction. The neutrinos travel through the earth to the SuperK neutrino observatory where they are detected.
So the signal is figured out.
And every star generates photons as well. The problem isn't necessarily one of noise, it's of extinction. There are a lot of things in the galaxy which absorb photons really easily, making signals difficult to propagate. Neutrinos solve this part of the problem.
Kind of like "Dude, Where's My Car?". Sure, it looked kinda funny in the trailer, and while I can't speak for the last 30 minutes of the movie, my thankfully waning memories of the experience suggest that the trailer consisted of the only funny parts in that entire movie.
"Also, isn't there something like an few minutes of latency for light to reach us from Mars? You can't even really do any really realtime interaction with the onboard computer on the Phoenix lander.. Imagine typing into a shell and waiting a minute for your characters to appear! Ouch! So I bet you they have to premeditate a lot of the changes they make to the software or operating environment way a head of time -- they probably just upload scripts of commands when updating the software or filesystem, etc."
Yes the lag time is several minutes, depending on the relative positions of the Earth and Mars. For the mars rovers the task is quite interesting. Imagine trying to control a remote controlled car around an obstacle course where you have to wait 20 minutes to see the results of your actions.
NASA wrote software for the rovers which makes the process largely automatic. They tell the rover to go to a certain place, and the rover has software which basically figures out the best way to get there.
That'd be impossibly slow and waaaay too complicated.
Of course if the NSA REALLY REALLY wanted some data off of some drive and everything else failed, I suppose this would work.
A spin current does not need to be 100% polarized, and I'm pretty sure this one is not.
The spin currents from ferromagnetic sources have a relatively low polarization. QPCs are much better.
All you need for a pure spin current is transfer of angular momentum in some direction without a net transfer of charge.
Spin-orbit can still be quite strong yes, but it is very dependant on the material.
An interesting way to think about it is that when you have a standard piece of conducting material, it's not that there is no current flowing in it while it sits there not hooked up to a source; actually the electrons go all over the place inside the material. Current flows right to left, left to right, but it all balances out and there is no net current. Resistive heating only occurs when you have net charge current.
In an ideal spintronics device you would have charged currents flowing just like in any other material, but there would be no NET charge current. The spin current can diffuse along your channel. Why is this better in terms of heat? I'd have to check, but I think you're on the right track with the magnetic dipole being much weaker than an electric monopole. 1/r^4 vs 1/r^2 IIRC.
One of the major benefits occurs if you can pass a coherent spin current along a channel. This leads to the possibility of quantum computations involving spins.
Spins are transferred from electron to electron as the spins flip. Imagine a series of bar magnets. You can flip one magnet and it will affect the energy of the next one, and then the next one etc. The exact solution is difficult to calculate quite often, but in general, if you have a high population of spin up electrons localized in one area, the spins will tend to diffuse away from that via a few mechanisms:
1. The spin ups will turn to spin downs and cause nearby spin downs to turn spin up. 2. The spin up electrons will move to the right (just picking a random direction), and this will be compensated for by having spin down move left. The result is a net spin current with no net charge current.
To generate this, a spin polarized charge current is generally used. In this paper they used a ferromagnet contact as a source. The setup is basically a 3-way intersection.
Lead 1 is just a floating lead not connected to any ground. Lead 2 is the ferromagnetic lead Lead 3 is a ground connection
A voltage is applied between Lead 2 and Lead 3 causing an electrical current to flow. The electrons come out of the ferromagnet partially polarized. This current then goes into the ground Lead 3. All charge current flows from Lead 2 to Lead 3. However, the excess spin up electrons in the junction cause spins to diffuse down the floating Lead 1. No charge current flows down Lead 1 because it has nowhere to go. The result is a net spin current with no net charge current.
That's what I was thinking... Basically use the DMCA against them. Find some way to encrypt all the data in ram such that it's never stored unencrypted. Or better yet, say it's encrypted already (null encryption? I don't know... I'm not a security expert).
That's not how they work at all. There's no current flowing through the nanoparticle layer. All that layer does is take UV photons and convert them into visible photons.
Voltage is not meaningless. The increase in voltage by adding this layer says something very important about the physics of the material. It's akin to taking your standard 12V car battery, coating the leads with mystery material and having it magically operate at 20V where the mystery material isn't any kind of EMF source.
Current can be made arbitrarily large by making a cell of arbitrary size. There is also a question of fill factor and peak power tracking, as the cell's output will depend on the load across it.
No you wouldn't. Just stick the mirror in lengthwise. The ship would have to be 16m LONG and 16 m HIGH, but it need only be as wide as your mirror is THICK.
Even still, a 16m wide boat is much easier to come by than a 16m wide rocketship.
The flat mirror would be a number of smaller ones, but the main focusing mirror would probably be a single piece AFAIK. Considering that high precision mirrors are ground to within atoms of an ideal shape, I doubt that the main mirror of a multimillion dollar telescope would be segmented.
You'd need a rocket ship 16m wide to get a 16m mirror into orbit...:)
How you can beat that though is have 2 say, 4m mirrors placed a few (hundred? thousand? million?) km apart to act as an interferometer. You'd get some crazy resolution with one of those, but the mechanics of setting up an interferometer are extremely difficult.
Yes, that does seem odd, but you have to take into account a number of factors. We have telescopes in Chile right now that can take clearer images than hubble in the IR range of the spectrum, but that changes as you go to shorter wavelengths. I'd imagine that this antarctic scope could greatly outperform hubble in the IR and perhaps optical, but maybe not the UV...
Slashdot Mirror
There are two types of planets: Earth-like and Jupiter-like. All planets are some linear combination of these. If we propose a unit vector E to be (1,0) and a unit vector J to be (0,1) any planet can be classified using a linear combination of these two vectors. Oh, and a planet's location in this orthogonal planet space does not need to be a unit vector. Venus would be something like 0.98E + 0J. Saturn would be something like 0E + 0.6J. Mercury would be something like 0.05E + 0J. I am unsure of what a 0.5E + 0.5J planet would look like. It would probably be a good place to look for short stocky people who like thick fog.
As of 6:31 pm PDT Views: 209 Thought it might be neat to see how many views the youtube video has as a function of time.
I vote for carrier pigeons. What other method is also edible?
The T2K http://jnusrv01.kek.jp/public/t2k/ experiment is basically a neutrino beam generator. A standard particle accelerator fires its beam into a target, generating a roughly collimated beam of neutrinos via a nuclear reaction. The neutrinos travel through the earth to the SuperK neutrino observatory where they are detected. So the signal is figured out. And every star generates photons as well. The problem isn't necessarily one of noise, it's of extinction. There are a lot of things in the galaxy which absorb photons really easily, making signals difficult to propagate. Neutrinos solve this part of the problem.
Kind of like "Dude, Where's My Car?". Sure, it looked kinda funny in the trailer, and while I can't speak for the last 30 minutes of the movie, my thankfully waning memories of the experience suggest that the trailer consisted of the only funny parts in that entire movie.
"Also, isn't there something like an few minutes of latency for light to reach us from Mars? You can't even really do any really realtime interaction with the onboard computer on the Phoenix lander.. Imagine typing into a shell and waiting a minute for your characters to appear! Ouch! So I bet you they have to premeditate a lot of the changes they make to the software or operating environment way a head of time -- they probably just upload scripts of commands when updating the software or filesystem, etc." Yes the lag time is several minutes, depending on the relative positions of the Earth and Mars. For the mars rovers the task is quite interesting. Imagine trying to control a remote controlled car around an obstacle course where you have to wait 20 minutes to see the results of your actions. NASA wrote software for the rovers which makes the process largely automatic. They tell the rover to go to a certain place, and the rover has software which basically figures out the best way to get there.
That'd be impossibly slow and waaaay too complicated. Of course if the NSA REALLY REALLY wanted some data off of some drive and everything else failed, I suppose this would work.
A spin current does not need to be 100% polarized, and I'm pretty sure this one is not. The spin currents from ferromagnetic sources have a relatively low polarization. QPCs are much better. All you need for a pure spin current is transfer of angular momentum in some direction without a net transfer of charge.
Spin-orbit can still be quite strong yes, but it is very dependant on the material. An interesting way to think about it is that when you have a standard piece of conducting material, it's not that there is no current flowing in it while it sits there not hooked up to a source; actually the electrons go all over the place inside the material. Current flows right to left, left to right, but it all balances out and there is no net current. Resistive heating only occurs when you have net charge current. In an ideal spintronics device you would have charged currents flowing just like in any other material, but there would be no NET charge current. The spin current can diffuse along your channel. Why is this better in terms of heat? I'd have to check, but I think you're on the right track with the magnetic dipole being much weaker than an electric monopole. 1/r^4 vs 1/r^2 IIRC. One of the major benefits occurs if you can pass a coherent spin current along a channel. This leads to the possibility of quantum computations involving spins.
Spins are transferred from electron to electron as the spins flip. Imagine a series of bar magnets. You can flip one magnet and it will affect the energy of the next one, and then the next one etc. The exact solution is difficult to calculate quite often, but in general, if you have a high population of spin up electrons localized in one area, the spins will tend to diffuse away from that via a few mechanisms:
1. The spin ups will turn to spin downs and cause nearby spin downs to turn spin up.
2. The spin up electrons will move to the right (just picking a random direction), and this will be compensated for by having spin down move left. The result is a net spin current with no net charge current.
To generate this, a spin polarized charge current is generally used. In this paper they used a ferromagnet contact as a source. The setup is basically a 3-way intersection.
Lead 1 is just a floating lead not connected to any ground.
Lead 2 is the ferromagnetic lead
Lead 3 is a ground connection
A voltage is applied between Lead 2 and Lead 3 causing an electrical current to flow. The electrons come out of the ferromagnet partially polarized. This current then goes into the ground Lead 3. All charge current flows from Lead 2 to Lead 3. However, the excess spin up electrons in the junction cause spins to diffuse down the floating Lead 1. No charge current flows down Lead 1 because it has nowhere to go. The result is a net spin current with no net charge current.
That's what I was thinking... Basically use the DMCA against them. Find some way to encrypt all the data in ram such that it's never stored unencrypted. Or better yet, say it's encrypted already (null encryption? I don't know... I'm not a security expert).
That's not how they work at all. There's no current flowing through the nanoparticle layer. All that layer does is take UV photons and convert them into visible photons.
Voltage is not meaningless. The increase in voltage by adding this layer says something very important about the physics of the material. It's akin to taking your standard 12V car battery, coating the leads with mystery material and having it magically operate at 20V where the mystery material isn't any kind of EMF source.
Current can be made arbitrarily large by making a cell of arbitrary size. There is also a question of fill factor and peak power tracking, as the cell's output will depend on the load across it.
No you wouldn't. Just stick the mirror in lengthwise. The ship would have to be 16m LONG and 16 m HIGH, but it need only be as wide as your mirror is THICK. Even still, a 16m wide boat is much easier to come by than a 16m wide rocketship.
The flat mirror would be a number of smaller ones, but the main focusing mirror would probably be a single piece AFAIK. Considering that high precision mirrors are ground to within atoms of an ideal shape, I doubt that the main mirror of a multimillion dollar telescope would be segmented.
You'd need a rocket ship 16m wide to get a 16m mirror into orbit... :)
How you can beat that though is have 2 say, 4m mirrors placed a few (hundred? thousand? million?) km apart to act as an interferometer. You'd get some crazy resolution with one of those, but the mechanics of setting up an interferometer are extremely difficult.
Yes, that does seem odd, but you have to take into account a number of factors. We have telescopes in Chile right now that can take clearer images than hubble in the IR range of the spectrum, but that changes as you go to shorter wavelengths. I'd imagine that this antarctic scope could greatly outperform hubble in the IR and perhaps optical, but maybe not the UV...
Not only that, but you can put up some filters and observe the sun itself.
Actually empty space has a temperature of 2.73 Kelvin.