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Government Science News

Anti-Matter Created By Laser At Livermore 465

zootropole alerts us to a press release issued today by Lawrence Livermore National Laboratory, announcing the production of 'billions of particles of anti-matter.' "Take a gold sample the size of the head of a push pin, shoot a laser through it, and suddenly more than 100 billion particles of anti-matter appear. The anti-matter, also known as positrons, shoots out of the target in a cone-shaped plasma 'jet.' This new ability to create a large number of positrons in a small laboratory opens the door to several fresh avenues of anti-matter research, including an understanding of the physics underlying various astrophysical phenomena such as black holes and gamma ray bursts." The press release doesn't characterize the laser used in this experiment, but it may have been this one.
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Anti-Matter Created By Laser At Livermore

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  • by Valacosa ( 863657 ) on Tuesday November 18, 2008 @01:38AM (#25797975)

    The anti-matter, also known as positrons...

    *Sigh*

    I guess the PR agent who wrote the story didn't even read the Wikipedia page on antimatter. [wikipedia.org] Either that, or he/she just isn't a good writer -- that statement implies that all positrons are anti-matter and all anti-matter is positrons. Only the first statement is true.

  • Re:Holy Mackerel! (Score:4, Informative)

    by AKAImBatman ( 238306 ) * <[moc.liamg] [ta] [namtabmiaka]> on Tuesday November 18, 2008 @01:51AM (#25798067) Homepage Journal

    Yeah, because NASA (and similar agencies around the world) have whopping piles of cash laying around for this.

    Yeah, research dollars would never fund anything like that. Except when they [wikipedia.org] do [wikipedia.org].

    Is it really so hard to click through the links? :-/

    FWIW, there are quite a few antimatter engines on the drawing board. They're only missing one key component: Antimatter. And this new technology may be the key to providing it in spades. (Relatively speaking, of course.)

  • by Anonymous Coward on Tuesday November 18, 2008 @01:55AM (#25798099)

    Either that, or he/she just isn't a good writer -- that statement implies that all positrons are anti-matter and all anti-matter is positrons. Only the first statement is true.

    Nice try, but not true. Your argument would be correct if the statement had read "Anti-matter, also know as positrons...", but it does not. Rather the author says "The antimiater, also known as positrons...".

    This sentence only refers to the antimatter created during this experiment. And, near as I can tell, positrons are indeed the only form of antimatter produced in the experiment.

    The lesson here - don't post smug messages denouncing someones incorrect grammar when their grammar is in fact correct. Check your facts.

  • Re:Holy Mackerel! (Score:5, Informative)

    by zippthorne ( 748122 ) on Tuesday November 18, 2008 @02:06AM (#25798165) Journal

    60e6*1e3 kcal / c^2= 2.8 kg [google.com] of antimatter will give any H-bomb look like.. uh.. something that's the same size as an H-bomb. H-bombs have been proposed (and postulated to have been built) that are larger than 60 MT, and a pop-gun typically has only a few Joules, so you'd need many orders of magnitude more than 2 kg of antimatter to make an H-bomb look like a pop-gun. something like.. four times the mass of mount Everest, in antimatter.

  • Re:Holy Mackerel! (Score:5, Informative)

    by AKAImBatman ( 238306 ) * <[moc.liamg] [ta] [namtabmiaka]> on Tuesday November 18, 2008 @02:32AM (#25798281) Homepage Journal

    Nukes have already been used

    Yeah, once. (Twice if you want to be pedantic.) Then never again. The whole point was that the display of force showed that the weapons were too dangerous to use. As long as the various sides have them pointed at each other, no one dares use them.

    The only reason why the Cold War was so terrible was that the USA and the USSR were both waiting for the other to attack. Since neither one liked each other much (for both idealogical and practical reasons) the chance that an armed conflict would happen between the two powers was pretty darn high. Except that an armed conflict might precipitate into a nuclear war should either side feel backed into a corner.

    Thus the reason why the US didn't win Vietnam. The chance of starting a nuclear war was too great to risk pressing the war to a conclusion. Which raised the (very legitimate) question of why we were even in the conflict to begin with.

  • Re:Holy Mackerel! (Score:5, Informative)

    by Ann Coulter ( 614889 ) on Tuesday November 18, 2008 @02:45AM (#25798371)

    It should be (60e6 * 1e3 kcal) / (2*c^2) = 1.39659835 since the normal matter that will also be annihilated will contribute to the mass-energy conversion.

  • Re:Holy Mackerel! (Score:5, Informative)

    by techno-vampire ( 666512 ) on Tuesday November 18, 2008 @03:07AM (#25798517) Homepage
    Nuclear devices in the megatons have only been deployed and detonated in a theater of openly declared war twice.

    If you're referring to Hiroshima and Nagasaki, you're wrong. Both of those devices were in the kilotons, not megatons.

  • Re:Where's the boom? (Score:5, Informative)

    by compro01 ( 777531 ) on Tuesday November 18, 2008 @03:24AM (#25798627)

    You are fantastically overestimating how much they made. 100 billion particles seems like a lot, but it's actually only about 9.1x10^-17 grams (91 attograms). You could likely be physically standing right in front of the thing, in the middle of the spray of particles, and not notice anything.

  • by hvm2hvm ( 1208954 ) on Tuesday November 18, 2008 @04:55AM (#25799101) Homepage
    They created billions of positrons with a high power laser. The antimass(?) of a positron is the mass of an electron or 9.1E-31. Let's round it up and say we have 1E+12 positrons. Combine them with 1E+12 electrons, you get
    9.1E-31*2E+12*(3E+8)^2=0.018 J.

    Now I'm guessing the laser used is pretty powerful and that it consumes a lot of energy. If we take the specs of the laser linked in the summary, then it used 150J on one pulse which is not the true amount of energy they put into the device (it says it takes 30minutes between pulses at full power). The energy used is thousands or millions of times greater than the energy gained.

    Of course, lasers might not be the most energy efficient way of creating antimatter but that doesn't change the fact that if you want to turn m matter into antimatter you will need at least 2*mc^2 energy (at least that's my intuitive guess).

    Nuclear devices emit huge amount of energy with relatively small energy inputs because the reaction is selfsustaining, something inside the reaction keeps it alive. What you want is something that destabilizes matter and makes it turn into energy by, say, throwing a special particle at neutrons and/or protons. Turning it into antimatter only to collide it with matter afterwards is just a huge waste of energy.
  • by hvm2hvm ( 1208954 ) on Tuesday November 18, 2008 @04:58AM (#25799109) Homepage
    Sorry, the result for the energy should be 0.16J not 0.018J.
    The rest of the post still stands.
  • Re:Russia (Score:3, Informative)

    by EdIII ( 1114411 ) * on Tuesday November 18, 2008 @06:18AM (#25799467)

    it is a representative democracy

    LOL!!! ROFL!! I laughed so hard my drink came out my nose!

    Representative Democracy? In what possibly way could you misconstrue that? The ruling elite (Elites, Politicians, Corporations, Military Industrial Complex) pass laws ALL THE TIME that no American wants.

    The fact that a small percentage of us voted was just the decision being made between a Douche and a Turd Sandwich. Senators and Congressmen create and pass laws and funding measures all the time that only benefit the corporations.

    Who really wanted the Patriot Act? My god, if you press me I can come up with at least 100 (no exaggeration) acts of congress that are appalling, and offensive to the average American.

    No Sir! Politics in America DOES not represent the interests of the American People, and when it *appears* to do so, it is only because it furthers the goals of those in power to keep them in power.

    LOL.

    Citizen participation in politics only occurs when they are under the illusion (delusion really) that they have any meaningful effect on the outcome. You want to have a real meaningful effect? Sink 100 million dollars into a lobbying firm and hope your "bribe" money is better than the competitions.

  • "The antimass(?) of a positron..."

    Anti-matter has mass, ordinary mass, just like matter.

  • by kmac06 ( 608921 ) on Tuesday November 18, 2008 @10:31AM (#25801169)
    As the other poster mentioned, they would repel each other, but that's not really the end of the answer. If they could be brought close enough together (which they certainly could), they still wouldn't annihilate, because of conservation laws. For one, charge would not be conserved (two positive charges would disappear). Lepton number conservation (think number of electrons conserved) and baryon number conservation (think number of protons conserved) would also be violated. It's for these same sort of conservation laws that negative electrons don't annihilate with positive protons all the time.
  • by rubycodez ( 864176 ) on Tuesday November 18, 2008 @10:55AM (#25801453)

    inertial confinement fusion with deuterium pellets surrounded by gold has already been done, but antimatter isn't a significant part of the fusion process. Even in this article, the amount of antimatter produced is miniscule

  • by severoon ( 536737 ) on Tuesday November 18, 2008 @04:57PM (#25807995) Journal

    Wow...reading this thread makes me a bit sad, and I can only hope that all the participants in this conversation up to now were not exclusively schooled in the US. (Sadly, I suspect it is so.)

    Physics is the study of manifestations and transformations of energy. One of the basic laws of physics is that energy is conserved. If you pump so many GeV of energy in the form of coherent radiation into gold atoms, it seems from this article that some fraction of that energy is converted into positrons. When those positrons collide with electrons in equal numbers (as they're sure to do in this universe given even a very short period of time), the matter-antimatter pair annihilate each other and mass is converted back to radiation energy.

    The amount of energy released in this annihilation is equal to the amount used to create the positrons in the first place, which is necessarily less than the energy of the laser light incident on the gold atoms. Some of that incident light is going to be lost knocking electrons off, knocking gold atoms out, heating the gold, getting absorbed and re-emitted as a different frequency of light, etc. We've only been looking at the actual point of energy transformation, too...if we go even further back in the chain, we have to look into the efficiency of the laser itself. Certainly less than 100% of the energy consumed by the device is emitted as a coherent light beam even before we look at how this beam is interacting with the gold.

    So, by definition, antimatter cannot be a first energy source in this universe. Antimatter could be useful as a means of storing a large amount of energy, but not as an ultimate source. (Unless we find a naturally occurring, ready source of antimatter that we can harvest, which would probably require a wormhole to an alternate universe and a means of controlling that wormhole. Uh oh, queue up the Star Trek / Stargate SG-1 nerds...)

That does not compute.

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