Mr Skeptic Posted March 4, 2008 Share Posted March 4, 2008 How would cosmic rays create antiparticles? Same as with particle accelerators. I understand that some cosmic rays are more powerful than what we can produce in a particle accelerator, though that may no longer be true. A few of them go so fast that people expected them to interact with cosmic background radiation to produce particle pairs, and slow them down. But with a matter target, lots of cosmic rays would have the energy for pair production. And the electric bill to run all those magnet tensors is HUGE. I don't doubt it, but in theory, you could instead extract energy from decellerating the particles. It would, of course, involve a very large decellerator. Link to comment Share on other sites More sharing options...
Riogho Posted March 4, 2008 Share Posted March 4, 2008 Same as with particle accelerators. I understand that some cosmic rays are more powerful than what we can produce in a particle accelerator, though that may no longer be true. A few of them go so fast that people expected them to interact with cosmic background radiation to produce particle pairs, and slow them down. But with a matter target, lots of cosmic rays would have the energy for pair production. It would be disgustingly hard to get a high enough concentration of cosmic rays, and when your anti particle was made, it would immediatly annihilate by the surrounding matter... What are you saying we could make this in, because I'm not seeing any machine that could take cosmic rays and shoot em in a vacuum AND have it create enough energy on impact with something to make matter and antimatter >.< But my engineering is pretty bad. I don't doubt it, but in theory, you could instead extract energy from decellerating the particles. It would, of course, involve a very large decellerator. It definitely wouldn't even be a 1:1 ratio of the energy needed to run the damn thing Link to comment Share on other sites More sharing options...
Prof.Marvel Posted March 5, 2008 Share Posted March 5, 2008 Are antimatters present anywhere in the universe. And is it really possible to create antimatters in Earth. It is my understanding that a positron is the antimatter counterpart of an electron and they certainly do exist on our planet. Positrons are the basis for PET (positron emission tomography) scans. Link to comment Share on other sites More sharing options...
Janus Posted March 5, 2008 Share Posted March 5, 2008 It is my understanding that a positron is the antimatter counterpart of an electron and they certainly do exist on our planet. Positrons are the basis for PET (positron emission tomography) scans. Positrons are emited naturally during some radioactive decays, this is known as beta+ emission. It happens when a proton in a nucleus converts to a neutron and positron. PET scans work by injecting such a positron emittng isotope into the person, then scanning the body for the gamma radiation emitted when the positrons mutally anihilate with electrons. Link to comment Share on other sites More sharing options...
antimatter Posted March 17, 2008 Share Posted March 17, 2008 Wouldn't that cause a massive amount of damage? It would spark a chain reaction of annihilation...that would be terrible... Link to comment Share on other sites More sharing options...
Riogho Posted March 17, 2008 Share Posted March 17, 2008 How would it be a chain reaction? Link to comment Share on other sites More sharing options...
antimatter Posted March 17, 2008 Share Posted March 17, 2008 Oh my mistake, I think I just got confused with something else, sorry. What I meant to say before I got confused was that wouldn't there have to be an enormous amount of antiparticles for the gamma rays to become noticeable? Link to comment Share on other sites More sharing options...
Riogho Posted March 17, 2008 Share Posted March 17, 2008 An electron-positron annihilation would cause quite a few gamma rays, enough to be detected anyways. Though I think more then one annihilation is occuring, I don't know for sure though. Link to comment Share on other sites More sharing options...
Klaynos Posted March 17, 2008 Share Posted March 17, 2008 An electron-positron annihilation would cause quite a few gamma rays, enough to be detected anyways. Though I think more then one annihilation is occuring, I don't know for sure though. I'm pretty sure it's 2, or maybe 4.... in nearly all cases.... Link to comment Share on other sites More sharing options...
antimatter Posted March 17, 2008 Share Posted March 17, 2008 I mean, it would make sense. While one electron-positron annihilation would be noticeable, I don't think it would be particularily useful. I do think there are multiple annihilations going on. I'm pretty sure it's 2, or maybe 4.... in nearly all cases.... Come to think of it, how large are these annihilations, if only 2-4 are used...? Link to comment Share on other sites More sharing options...
Klaynos Posted March 17, 2008 Share Posted March 17, 2008 Certainly in the case I investigated a couple of years ago it was 2 gamma photons per annihilation... each one was 0.51MeV and they where moving at exactly opposite directions to each other. Link to comment Share on other sites More sharing options...
antimatter Posted March 17, 2008 Share Posted March 17, 2008 Alright, in that case it makes more sense, I thought the gamma ray emmision was much much smaller. Thanks for clearing that up. Link to comment Share on other sites More sharing options...
dirtyamerica Posted August 13, 2008 Share Posted August 13, 2008 I read an article recently about matter/antimatter. The author asked something like: If our immediate universe is made up of matter then where did all the antimatter go? or why do we have excess matter left over? Sorry, I don't remember the source of the article but this does seem like a good place to ask. Link to comment Share on other sites More sharing options...
Klaynos Posted August 13, 2008 Share Posted August 13, 2008 I read an article recently about matter/antimatter. The author asked something like: If our immediate universe is made up of matter then where did all the antimatter go? or why do we have excess matter left over? Sorry, I don't remember the source of the article but this does seem like a good place to ask. That question is one of the current great mysteries of astrophysics.. Link to comment Share on other sites More sharing options...
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