Air Force Researching Antimatter Weapons 1062
mlmitton writes "The San Francisco Chronicle is reporting that the Air Force is actively pursuing antimatter weapons. Such weapons would easy eclipse nuclear weapons in power, e.g., 1 gram of antimatter would equal 23 space shuttle fuel tanks of energy. Perhaps more interesting, after an initial inquiry by the Chronicle in the summer, the Air Force issued a gag order that prohibits any Air Force employee from discussing antimatter research or funding."
1gm antimatter = 39 kT TNT (Score:5, Informative)
1948 units, 71 prefixes, 28 functions
You have: grams*c^2
You want: tonnes-tnt
* 19487.022
/ 5.1316205e-05
So 1 gram antimatter + 1 gram matter is about 39 kT of TNT. Hiroshima was about 20 kT, Nagasaki was 13 kT, so one gram antimatter would release just a scosh more than both devices.
So let us use a bit more sensible units than "shuttle fuel tanks".
However, the costs of manufacturing the antimatter, and the size of the containment system, and the fail-null mode of antimatter vs. the fail-safe mode of a nuke (a nuke may leak, but it will not detonate without everything going just right), would lead me to wonder about the utility of an antimatter weapon.
"23 space shuttle fuel tanks" and the "gag order" (Score:5, Informative)
1 gram of antimatter would equal 23 space shuttle fuel tanks of energy.
I thought the standard unit of explosive power was the ton of dynamite...
Perhaps more interesting, after an initial inquiry by the Chronicle in the summer, the Air Force issued a gag order that prohibits any Air Force employee from discussing antimatter research or funding
This isn't really that interesting or even unusual: Uncle Sam frequently limits what military folks can say about ongoing projects. There is a classification called "Sensitive But Unclassified", or SBU, whcih means the info is not classified as such (Secret, TS, etc.) but it is still not for public disclosure. (Years ago SBU was called "For Official Use Only" or FOUO.) Budgets are generally considered at least SBU, so it should be no suprise that the budget is not publicized.
Re:How about research them... (Score:5, Informative)
Re:Some things I don't understand about anti-matte (Score:4, Informative)
Re:1 gram of anti matter? (Score:2, Informative)
Comment removed (Score:5, Informative)
Medical (Peaceful) Uses of Positron (Score:5, Informative)
For a balanced view, it is important to realize that anti-matter physics have yielded substantial medical and non-military benefits already. Many people probably already encountered various applications of this technology without realizing it.
For example, Positron Emission Tomography (PET) is a very useful clinical and medical research tool for brain and cardiac functional imaging. See: Positron Emission Tomography [triumf.ca]
Re:Energy Conversion (Score:5, Informative)
Still a hell of a chest X-ray to give the planet.
Re:Some things I don't understand about anti-matte (Score:2, Informative)
Anti-matter can't touch matter.. but you can build anti-matter containments.. even devices, but I suspect we are very far from this, as it takes a lot of anti-matter to create something on such a large scale. We'll probably use a form of particle trickery, directing the resulting anti-matter towards matter. Viola. Weapon.
Re:Really... (Score:4, Informative)
We've got the bomb. In fact we've got nuclear submarines so fucking quiet you wouldn't even know their in your harbor just chuck full of the little bastards. However, much like spitting into the wind, using said weapons means we get to glow in the dark as well.
Anti-matter weapons don't have this spit in face problem. We could drop a anti-matter bomb on Iran and flatten the whole country to within an inch of sea level and nobody is going to be dying of cancer from the nuclear fallout.
It's like the bomb, only much better.
Re:How about research them... (Score:5, Informative)
So, you can use it to create a nice bomb, but it's equivalent to pumping up a pressurized bottle with a lot of air -- the only energy that's going to come out is the energy that you've put in to create the anti-matter. You make some anti-matter, find a way to confine it and later release it in a controlled fasion and you get a very nice bomb which is incredibly powerful given the mass of the active ingredients. But you cannot use it as an energy source because unlike coal, oil, natural gas and uranium, it isn't freely available: you have to make it.
This is in stark contrast with nuclear fusion and fission: there is lots of available material lying around in the ground and in the seas, just waiting to be extracted and used. While you can find ways of generating anti-matter without putting too much energy into the process (eg, by triggering nuclear decay) you just don't get that much mass very quickly. Unless, of course, you've got a right raging nuclear reaction going, and, then, well, your problems of bomb making are pretty well solved.
Re:Some things I don't understand about anti-matte (Score:4, Informative)
The only mechanisms we know of to create antimatter are UNBELIEVABLY power-hungry. The technology to manufacture even a mere gram of antimatter does not exist. So, the answer to your question -- we really have no idea. We can't manufacture meaningful amounts of antimatter at all, so the question of when it would get manufactured is something of a moot point.
What about the radiation involved? We've measured the rays that result from minor, single-atom collisions, but what happens when the collision is actually big enough to damage something?
IANANP (I am not a nuclear physicist), but I don't believe it would be significant. Nuclear weapons have two major sources of residual radiation (fallout): fission byproducts and induced radioactivity caused by neutron bombardment. Antimatter bombs wouldn't produce either. The radiation produced by a matter-antimatter reaction is high-energy gamma rays -- the explosion's extreme energy levels would probably manage to split or fuse a few atoms, and probably create very small amounts of radioactive material, but without fission byproducts or neutron flux you shouldn't see any large-scale radioactivity. The explosion would essentially look and behave just like a nuclear explosion (thermal pulse, mushroom cloud, shock wave, etc.) but without the fallout.
How do you propel something like this? Magnets? Or am I wrong in assuming anti-matter can't touch anything?
You are correct -- matter-antimatter collisions are bad news, and you can't allow the antimatter to touch any matter until the desired moment of explosion. Fortunately, antiprotons and antielectrons (positrons) are both electrically charged, and can therefore be magnetically contained in a vacuum to keep them from contacting any matter. A (very simple and dangerous) bomb design might be as simple as a containment shell with antimatter inside. You drop it on the target, the bomb ruptures and releases antimatter, BOOM.
The real problem is that the failure mode of antimatter weapons (at least ones that relied on pre-manufactured antimatter) is so damned dangerous. If the circuitry in a nuclear weapon fails, no biggie -- the bomb just doesn't detonate. Even in the worst case all that happens with a nuke is leakage of radioactive material. In fact, even an accidental critical mass isn't enough to produce a large-scale explosion -- unless you contain everything just right it just doesn't give you a big blast.
With an antimatter bomb, the opposite is true. You have to contain everything just right, because the second you don't, BOOM.
Re:Uh, it's still FOUO everywhere else but to you. (Score:3, Informative)
Re:Energy Conversion (Score:1, Informative)
Actually (Score:2, Informative)
Ummmm... actually... there's plenty of anti-matter around. It's everywhere actually, poping into an out of existance all the time on a quantum scale. The tricky part is botteling it before it annihalates with the virtual matter particle that was spontaneously created with it.
Still, I bet you could get more bang out of evaporating quantum black holes. You just need a Tevatron to make them.
Re:Energy Conversion (Score:1, Informative)
Re:1 gram of anti matter? (Score:3, Informative)
You could of course get more complicated results, but you'd need to put in extra energy to start with so that you can create other particle/antiparticle pairs (since all the numbers have to balance out in the end), and since we're usually talking about something like electron-positron collisions, there's not much out there with lower mass-energy to be formed.
The perfect annihilation is why anything involving antimatter is so attractive from an energetic point of view: its a 100% efficient (since we're talking about individual annihilations, not an ensemble of them with someone trying to extract energy from the whole mess, we're not violating any thermodynamic laws) process that converts one form of energy (that is, the mass-energy of the particle-antiparticle pair) to another (the resultant photons). And it has no byproducts.
Of course, you could never use it as an energy 'generation' scheme since there's not really any antimatter out there to go and harvest thanks to that weird breaking of the symmetry between matter and antimatter. There are processes that do not have that symmetry (i.e. CP violation,
As a consequence, it's also the classic bomb-like weapon: 'pack a lot of metastable or unstable energy into something and drop it on your target'.
However, given the difficulty involved in making macroscopic quantities of this stuff, we could probably make a couple of those carbon nanotube space ladders with the budget to build a single significantly-sized bomb.
Re:Weapon research == Power plant research. (Score:2, Informative)
Or perhaps you're thinking that antimatter would be an energy weapon, much like a thermonuclear device, that liberates large amounts of electromagnetic radiation.
Fortunately, the classic problems with radioactive materials -- particularly, long-term storage and environmental effects of their byproducts (whether in cannisters or in the form of fallout) -- should not exist with antimatter weapons.
Wrong kind of radioactive (Score:5, Informative)
In a fission reaction the fallout comes from two sources. The first is the by-products of the fission reaction. I believe it is radioactive isotopes of Cesium and Potassium. This radioactive particles combine with the uranium/plutonim that did not fission and get distributed as fallout.
A pure fusion bomb, e.g. neutron bomb, has only a fusion reaction and thus theoretically produces no radioactive fallout. However in practice a fission reaction is used to create the pressure and heat needed to start the fusion reaction.
See the Special Weapons Primer at http://www.fas.org/nuke/intro/nuke/index.html [fas.org] for more info.
slight correction... (Score:5, Informative)
Re:Energy Conversion (Score:4, Informative)
A kilo of antimatter reacting with a kilo of matter releases 2kg x (300,000,000 m/s)^2 = 1.8e17 Joules. The specific combustion energy of TNT is 4.6e6 J/kg, hence 1 kt TNT = 4.6e12 J, 1 Mt TNT = 4.6e15 J. Therefore 1.8e17 J / 4.6e15 J ~= 40 MT of TNT.
You get about 70 times as much energy as you would from fusing 2kg of hydrogen into helium. But then fusion is a viable power source, whereas antimatter is at best a battery. Unless we find a way to make antimatter without having to make matter as well; then the reaction would be a net gain in usable energy (at the expense of matter in the universe, of course)
Re:How about research them... (Score:2, Informative)
However, someone shot with a tumbling 5.56 will be more likely to sustain tremendous internal injuries that will require immediate medical attention or otherwise result in death.
The 5.56 is smaller, but much much nastier.
Re:Energy Conversion (Score:5, Informative)
So, here we go... 1 gram of antimatter -> burning libraries of congress(es?):
For the sake of argument, lets assume that the Library of Congress is entirely non-flamable and only the books contribute to the heat. Furthermore, lets assume that all the books are made of 100% wood or equivilant.
Now, 1 gram of wood when completely burned produces 3000 calories [cartage.org.lb].
The Library of Congress contains approximately 128 million [loc.gov] items. Again, some of these are recordings of various natures and will not burn as well as books... so to compensate we'll deviate from our initial assumptions and assume that the burning of the 530 miles [loc.gov] of bookshelves compensate for any lack of flamability of the old records.
So... our average paperback weighs under 1lb [schoenhofs.com] and our average hardcover book weighs between 1 and 2lbs [schoenhofs.com]. Seems reasonable enough. Lets assume a distribution between hardcover and paperbacks so as the average book weight in the LOC is 1lb.
Now, Google can help us some more here. Our friendly search engine lets us know that one pound is 453.59237 grams [google.com]. We'll round that off to 453 grams, since we're averaging book weight anyway.
So, the LOC has (453*128,000,000) or 57,984,000,000 grams worth of books. At 3000 calories per gram, burning down the LOC would produce 173,952,000,000,000 calories of energy. For the sake of sanity, lets convert that to joules. Google says that 173 952 000 000 000 calories = 7.27815168 × 10^14 Joules [google.com]
Now, our space shuttle main tank (and engines, NOT including boosters which are more powerful) produce 1,987,500,000 Watts [hypertextbook.com] of energy, and burn for 8.5 minutes [daviddarling.info]. That's (510*1,987,500,000) 1013625000000 Watt/seconds of energy. Converted to joules, that is remarkably 1013625000000 Joules [google.com].
So.. One space shuttle fuel tank of energy is 1013625000000 Joules. 23 space shuttle tanks of energy is 23313375000000 Joules. For convienence, one space shuttle tank is 0.23313375x10^14 joules.
So... it comes down to one burning LOC is 7.27815168 × 10^14 joules. 23 space shuttle fuel tanks are 0.23313375*10^14 joules. So, one gram of antimatter combining with one gram of matter is approximately 0.032 Burning Libraries of Congress(es?). I actually expected it to be more.
Now how do I get Google to include space shuttle fuel tanks and burning libraries of Congress(es?) as acceptable measurements?
fantasy and unimaginable budget plans (Score:5, Informative)
With antimatter this problem is far worse, because while fission and fusion occur throughout the reaction volume, the matter-antimatter reaction occurs only on a contact surface.
It's exceedingly difficult to get a major explosion with antimatter.(Tiny ones are not hard, since the square-cube law gives you more surface area per volume as the scale shrinks.)
Also, with production technology we can reasonably foresee, antimatter is impossibly expensive for weapons applications.
Even the US military has finite budgets. The cost of burning a city down with conventional weapons is large but not infinite. We won't get the price down below US$ 60.e6/mg using foreseeable Earth-based technologies and, at 43 kT/gm of antimatter, we're talking roughly US$ 1.4e9 per kiloton !!!!!!!!! Even the Pentagon's budget isn't THAT large...
Re:Pointless. Maybe to you Leftist Peaceniks... (Score:2, Informative)
Re:How about research them... (Score:3, Informative)
Re:Weapon research == Power plant research. (Score:3, Informative)
True, antimatter alone is as stable as normal matter. However, problems arise if you bring anti- and normal matter together. And in our world made up of normal matter, this is almost unavoidable unless some elaborate containment devices are used...
Re:Anti-Matter Resch. (Score:5, Informative)
And the article didn't mention the chief problem with storing anti-matter. You can't allow it to touch anything. At all. It has to be in a vacuum container and make no contact with the edges. Otherwise, you'll get an explosion.
NASTY PICTURE WARNING (Score:4, Informative)
Re:Anti-Matter Resch. (Score:4, Informative)
Re:Wrong kind of radioactive (Score:5, Informative)
Re:fantasy and unimaginable budget plans (Score:3, Informative)
Re:Energy Conversion (Score:3, Informative)
Do we need any more proof this is a type 13 planet in it's final stages? I think not
Re:Plutonium (Score:5, Informative)
Daghlian was trying to find the practical (=just barely subcritical) arrangement of cube of tamper material (tungsten carbide) which would be completely surrounding a solid 6.2 kg sphere of delta-phase of Pu239. The carbide bricks functioned as neutron reflector also. Daghlian was working very slowly as he was getting close to critical configuration (neutron reflection increased reactivity). One of the heavy bricks felt out of his hand - on top of the Pu sphere and the system went critical. Daghlian trew the brick quickly away and disasembled the system into more strable configuration, etc. He got just above letal dose so he was dying very slowly.
Slotin was demonstrating for his colleagues reactivity of Pu depending on reflection of neutrons from berylium cover (Be holow hemispheric cover surrounding Pu sphere which was sitting half-embeded within another large Be hemispheric stand). The Be cover slipped, enclosed the Pu sphere, the system went critical, there was flash, Slotin took it apart with his bare hands (to save his colleagues) and got huge dose which killed him few days later.
Re:Weapon research == Power plant research. (Score:2, Informative)
Re:Anti-Matter Resch. (Score:1, Informative)
The thing to worry about is fusion bombs. In the classic designs, the trigger is a fission bomb, which makes it difficult and expensive. With antimatter for the trigger, a fusion bomb would become fairly easy. You might be able to build it without any radioactives at all, which would be really scary, although less clever designers should probably design it around a slightly-enriched uranium spark plug to guarantee ignition.
Here's a question to ponder: How much antimatter take, and how deep in does it need to be delivered, to ignite thermonuclear burning in the surface of a star?
Re:Anti-Matter Resch. (Score:2, Informative)
Consider that the electron is moving in south east direction and positron in north east. When they collide their north - south momentum will cancel out. Now the only remaining momentum is in the east direction. This momentum will be the momentum of the photon moving in the east direction. The reason the momentum cant be conserved during head on collison is that the resultant momentum has to be zero and single photon will have a mometum.
Errm, no you can't.
Einstein told us that as far as the laws of physics are concerned, one reference frame is as good as another. Now imagine you are sitting near to the the center of mass of the electron and positron and moving along with it. In your frame you see the two particles moving towards a head-on collision and with no net momentum. After the collision you will see at least one photon (by conservation of mass-energy) with zero net momentum (by conservation of momentum). The only way to get net zero momentum is by having at least two photons, travelling in suitable directions, since every photon carries momentum.If you bring conservation of angular momentum into play, there is another wrinkle. The electron and positron each have a half-unit of intrinsic angular momentum, called "spin" for brevity. A photon has unit spin. So the two initial particles can have either net zero spin (the two angular momenta are equal, opposite and cancel) or net unit spin. After the collision, the photons each have unit spin and so the net spin is either zero or two, depending on whether the spins are opposite or aligned respectively.
Spot the problem?
If the initial total spin of the two particles is unity, three photons have to be created to ensure that all the conservation laws are satisfied.
In the center of mass frame of reference, the three photons have equal momenta (and so have equal energy and are directed at an angle of 120 degrees from each other) and two of them have spins which are oppositely aligned.Paul
Re:print(Weapon research == basic research); (Score:4, Informative)
Re:Weapon research == Power plant research. (Score:3, Informative)
Slotin had been instructing a colleague, Alvin C. Graves, who was to replace him at the Omega Site. Also present was S. Allan Kline, a 26-year-old graduate of the University of Chicago, who had been called over to observe the procedure. Five other colleagues were close by as Slotin, a Canadian physicist from Winnipeg who had been part of the team that created the atomic bomb, performed the action that would bring into close proximity the two halves of a beryllium-coated sphere and convert the plutonium to a critical state.
With his left thumb wedged into a cavity in the top element, Slotin had moved the top half of the sphere closer to the stationary lower portion, a micro-inch at a time. In his right hand was a screwdriver, which was being used to keep the two spheres from touching. Then, in that fatal moment, the screwdriver slipped. The halves of the sphere touched and the plutonium went supercritical.
The chain reaction was stopped when Slotin knocked the spheres apart, but deadly gamma and neutron radiation had flashed into the room in a blue blaze caused by the instantaneous ionization of the lab's air particles. Louis Slotin had been exposed to almost 1,000 rads of radiation, far more than a lethal dose. Kline, who had been three or four feet away from Slotin, received between 90 and 100 rads, while Graves, standing a bit closer, received an estimated 166 rads.
http://www3.sympatico.ca/lavitt/louisslotin.htm
The accident involving Daghlian occured in August, oddly enough again on a 21st.
Re:Anti-Matter Resch. (Score:3, Informative)
Correct me if I'm wrong, but I thought that fission was caused by low energy neutrons. Gamma rays, and even high energy massive particles would not result in fission in any nearby fissile material.