4 ms·

When the photons collide, the researchers believe that a significant number of them will turn from light to matter — more specifically, into an electron and a p

When the photons collide, the researchers believe that a significant number of them will turn from light to matter — more specifically, into an electron and a positron. So we could use this within our warp core to power our warp field generators? How much energy would we have to expend to separate the positron from the electron and keep them separated? What does that give us in terms of energy storage efficiency, compared to storing electrical charge within a lithium battery?

kachnuv_ocasek 12y ago
Extremely infeasible.
- stephengillie 12y ago
  That's an extremely pessimistic reaction! I think such a device will at least be possible, and that we'll eventually engineer the energy density of it down to be comparably efficient. And we've got to power the warp field with something, so what are our most energy-dense options?
  - 27182818284 12y ago
    >And we've got to power the warp field with something, so what are our most energy-dense options? The most energy to mass ratio is antimatter, which is why it is chosen as the substance for Star Trek TNG to power the warp core. Second place is helium-3 if you count helium-3 fusion.
  - darkmighty 12y ago
    Storing antimatter is an engineering nightmare. It's hard enough to store chemicals that react with lots of things, imagine storing something which reacts releasing insane energies with all matter. You have to confine it perfectly using external fields. In other words, not an easy task. (CERN has a trap that was demonstrated to have formed just a few antihydrogen atoms) Not that we have any applications for it with the current production efficiency.
    - stephengillie 12y ago
      Are you implying that, with current technology, we may expend more energy confining antimatter than we could derive from a controlled annihilation?
      - BugBrother 12y ago
        Antimatter production/storage is an old subject. This is a book from 1988 by a favorite author Robert L Forward (the worst author from which I regularly bought books in hardcover; I just read them for the physics). http://books.google.ro/books/about/Mirror_matter.html?id=GS4bAQAAIAAJ&redir_esc=y http://books.google.ro/books/about/Mirror_matter.html?id=GS4... It was based on his report for NASA. I read the review: "He took the giggle factor out of antimatter"(!). The main point was that if machines were built to create antimatter (instead of Nobel prizes), it wasn't so crazy to produce. But as people are explaining to you, storage [of "large" masses like microgram] is still not solved. Afaik, at least.
    - al2o3cr 12y ago
      Perhaps more importantly, there's the messy consequence that those external fields only work on charged particles. You could (in principle) keep positrons and antiprotons together in a very hot plasma under magnetic confinement, but every pair that binds together into a neutral hydrogen atom can immediately escape and annihilate - turning carefully-stored fuel into gamma rays...
      - stephengillie 12y ago
        So you couldn't very well keep them together :)
    - jessriedel 12y ago
      To my understanding, this isn't correct. Storing anti-matter isn't really that hard. The Tevatron would store anti-protons in the recycler for hours, and I'm sure if it was important we could engineer much more efficient mechanisms. No, the hard part is creating the anti-matter in the first place and then cooling it down to a reasonable temperature at which it can be stored. All of our mechanisms for creating anti-matter generate anti-particles traveling at fantastic, highly relativistic speeds (and also consume much, much more energy to create then they contain in mass energy). Cooling them down without loosing them all to annihilation is very difficult. But once they're cool, it's not so bad.
- sitkack 12y ago
  I am going to cite Clarke's [0] first law. | When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong. [0] http://en.wikipedia.org/wiki/Clarke's_three_laws http://en.wikipedia.org/wiki/Clarke's_three_laws
  - kachnuv_ocasek 12y ago
    Well, I'm neither distinguished nor elderly scientist, so I may be right.
    - sitkack 12y ago
      May you grow old, earn awards and be proven wrong.
noobermin 12y ago
In this case the energy that goes into creating the e+e- pairs far outweighs the energy you get out. For example, given that this is Quantum Mechanics, there is a non-zero but not necessarily close to one probability of creating a pair from a given pair of photons. One could imagine the other light that didn't interact would just escape to the environment. You can conceptualize this as an photon produced to pair created efficiency, and I don't see it for any reason being very big. Then again, I'm not sure I understand the experiment, for example, I'm not sure how a blackbody spectrum helps in the breit-wheeler process. I think that the light colliding at a perpendicular incidence helps, but other than that, I can't see how the spectrum of radiation matters...like how is using a blackbody spectrum is better than, say, a monochromatic laser? I think I'd have to look at the paper once it gets out.

kachnuv_ocasek 12y ago

Extremely infeasible.

stephengillie 12y ago
That's an extremely pessimistic reaction! I think such a device will at least be possible, and that we'll eventually engineer the energy density of it down to be comparably efficient. And we've got to power the warp field with something, so what are our most energy-dense options?
- 27182818284 12y ago
  >And we've got to power the warp field with something, so what are our most energy-dense options? The most energy to mass ratio is antimatter, which is why it is chosen as the substance for Star Trek TNG to power the warp core. Second place is helium-3 if you count helium-3 fusion.
- darkmighty 12y ago
  Storing antimatter is an engineering nightmare. It's hard enough to store chemicals that react with lots of things, imagine storing something which reacts releasing insane energies with all matter. You have to confine it perfectly using external fields. In other words, not an easy task. (CERN has a trap that was demonstrated to have formed just a few antihydrogen atoms) Not that we have any applications for it with the current production efficiency.
  - stephengillie 12y ago
    Are you implying that, with current technology, we may expend more energy confining antimatter than we could derive from a controlled annihilation?
    - BugBrother 12y ago
      Antimatter production/storage is an old subject. This is a book from 1988 by a favorite author Robert L Forward (the worst author from which I regularly bought books in hardcover; I just read them for the physics). http://books.google.ro/books/about/Mirror_matter.html?id=GS4bAQAAIAAJ&redir_esc=y http://books.google.ro/books/about/Mirror_matter.html?id=GS4... It was based on his report for NASA. I read the review: "He took the giggle factor out of antimatter"(!). The main point was that if machines were built to create antimatter (instead of Nobel prizes), it wasn't so crazy to produce. But as people are explaining to you, storage [of "large" masses like microgram] is still not solved. Afaik, at least.
  - al2o3cr 12y ago
    Perhaps more importantly, there's the messy consequence that those external fields only work on charged particles. You could (in principle) keep positrons and antiprotons together in a very hot plasma under magnetic confinement, but every pair that binds together into a neutral hydrogen atom can immediately escape and annihilate - turning carefully-stored fuel into gamma rays...
    - stephengillie 12y ago
      So you couldn't very well keep them together :)
  - jessriedel 12y ago
    To my understanding, this isn't correct. Storing anti-matter isn't really that hard. The Tevatron would store anti-protons in the recycler for hours, and I'm sure if it was important we could engineer much more efficient mechanisms. No, the hard part is creating the anti-matter in the first place and then cooling it down to a reasonable temperature at which it can be stored. All of our mechanisms for creating anti-matter generate anti-particles traveling at fantastic, highly relativistic speeds (and also consume much, much more energy to create then they contain in mass energy). Cooling them down without loosing them all to annihilation is very difficult. But once they're cool, it's not so bad.
sitkack 12y ago
I am going to cite Clarke's [0] first law. | When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong. [0] http://en.wikipedia.org/wiki/Clarke's_three_laws http://en.wikipedia.org/wiki/Clarke's_three_laws
- kachnuv_ocasek 12y ago
  Well, I'm neither distinguished nor elderly scientist, so I may be right.
  - sitkack 12y ago
    May you grow old, earn awards and be proven wrong.

noobermin 12y ago

In this case the energy that goes into creating the e+e- pairs far outweighs the energy you get out. For example, given that this is Quantum Mechanics, there is a non-zero but not necessarily close to one probability of creating a pair from a given pair of photons. One could imagine the other light that didn't interact would just escape to the environment. You can conceptualize this as an photon produced to pair created efficiency, and I don't see it for any reason being very big. Then again, I'm not sure I understand the experiment, for example, I'm not sure how a blackbody spectrum helps in the breit-wheeler process. I think that the light colliding at a perpendicular incidence helps, but other than that, I can't see how the spectrum of radiation matters...like how is using a blackbody spectrum is better than, say, a monochromatic laser? I think I'd have to look at the paper once it gets out.