rebelion Posted March 3, 2009 Posted March 3, 2009 i was wondering about the nature of antimatter and matter and the hypothesis based n it , well the s.symetrie theory says that antimatter travel in the opposite sense of time than ours but in the other hand we can create antimatter in laboratory and they didnt go back in time so can someoe please explain this to me
Klaynos Posted March 3, 2009 Posted March 3, 2009 I think you'll find that what the theory actually tells us is that antimatter can be modelled as matter moving backwards in time, but we assume it is infact anti-matter and not matter moving backwards in time because the other would break causality.
rebelion Posted March 3, 2009 Author Posted March 3, 2009 so if i get it properly ,what s.symetrie theory call anti-matter is only the status of matter going back in time ,and the actual anti-matter which is anti-matter+matter=pure enenrgy r two different things?
Klaynos Posted March 3, 2009 Posted March 3, 2009 so if i get it properly ,what s.symetrie theory call anti-matter is only the status of matter going back in time ,and the actual anti-matter which is anti-matter+matter=pure enenrgy r two different things? No, they are the same thing. Anti-matter is identical to matter moving backwards in time. Matter is identical to anti-matter moving backwards in time.
rebelion Posted March 3, 2009 Author Posted March 3, 2009 thanks but my question is ,is the concept of anti-matter used in s.symetrie theory is the same concept used in the anti-matter/matter reaction like those that were used in the CERN and fermilab ? or they just have the same notation?
Klaynos Posted March 3, 2009 Posted March 3, 2009 thanks but my question is ,is the concept of anti-matter used in s.symetrie theory is the same concept used in the anti-matter/matter reaction like those that were used in the CERN and fermilab ? or they just have the same notation? They are the same.
rebelion Posted March 3, 2009 Author Posted March 3, 2009 oh, thank u ;what confused me is that the anti-matter cerated in the CERN didnt travel in time while it should be
swansont Posted March 3, 2009 Posted March 3, 2009 oh, thank u ;what confused me is that the anti-matter cerated in the CERN didnt travel in time while it should be I think you're misunderstanding the situation. There are three symmetries involved: charge, parity, and time-reversal. The combination of all three are thought to be a conserved quantity. But if you take a particle and look at the reversal of charge and parity, you get antimatter. So matter looks indistinguishable from antimatter traveling backward in time, or vice-versa. Here's more on CPT symmetry http://www.lbl.gov/abc/wallchart/chapters/05/2.html 1
cameron marical Posted March 4, 2009 Posted March 4, 2009 how could someone get matter traveling back in time without actually doing it?
Klaynos Posted March 4, 2009 Posted March 4, 2009 how could someone get matter traveling back in time without actually doing it? It's indistinguishable from antimatter and we can create that...
cameron marical Posted March 4, 2009 Posted March 4, 2009 how do you create it? please excuse the curiosity driven pushiness fora answers.
swansont Posted March 4, 2009 Posted March 4, 2009 Radioactive decay, or from a high energy photon or collisions of other particles
cameron marical Posted March 5, 2009 Posted March 5, 2009 high energy photon. like a realy high powered laser? and i though that radioactive decay is just matter thats throwing about crazy protons all over the place.?
swansont Posted March 5, 2009 Posted March 5, 2009 high energy photon. like a realy high powered laser? and i though that radioactive decay is just matter thats throwing about crazy protons all over the place.? High-powered lasers have lots of photons, but the individual photons are generally not of high energy. The photons for production of an electron-positron pair has to be at least 1.02 MeV, which is several hundred thousand times higher in energy than a visible photon. Radioactive decay is any transformation of a nucleus, and can include emissions of positrons or antineutrinos. Your body undergoes such a process several thousand times every second. (mostly decay of K-40 and C-14)
cameron marical Posted March 8, 2009 Posted March 8, 2009 High-powered lasers have lots of photons, but the individual photons are generally not of high energy. The photons for production of an electron-positron pair has to be at least 1.02 MeV, which is several hundred thousand times higher in energy than a visible photon. gamma rays? Radioactive decay is any transformation of a nucleus, and can include emissions of positrons or antineutrinos. Your body undergoes such a process several thousand times every second. (mostly decay of K-40 and C-14) what do you guys keep high energy photons and radioactive decay in?
swansont Posted March 8, 2009 Posted March 8, 2009 gamma rays? Typically, yes. Gammas are photons which come from nuclear interactions. what do you guys keep high energy photons and radioactive decay in? In what? I'm not sure I understand the question.
cameron marical Posted March 9, 2009 Posted March 9, 2009 In what? I'm not sure I understand the question. do you guys contain these particles in something? or just get them on spot from something? if the first, what in?
Klaynos Posted March 9, 2009 Posted March 9, 2009 do you guys contain these particles in something? or just get them on spot from something? if the first, what in? We keep our radioactive samples for teaching in lead boxes... as for photons you can't store them as they are, they move at the speed of light.... Antimatter can be contained as long as it is charged by using EM fields.
swansont Posted March 9, 2009 Posted March 9, 2009 You also tend to seal the source so that you don't contaminate everything. Then the lead-lined box, for shielding.
cameron marical Posted March 11, 2009 Posted March 11, 2009 why is led so special? isnt it just a slightly radioactive substance in itself? or is it toxic, maybe.
insane_alien Posted March 11, 2009 Posted March 11, 2009 lead is dense, it blocks gamma rays very well and completely blocks alpha and beta radiation at the thicknesses needed to shield against gamma. its not radioactive but it is toxic if ingested.
Klaynos Posted March 11, 2009 Posted March 11, 2009 why is led so special? isnt it just a slightly radioactive substance in itself? or is it toxic, maybe. It's really dense, and quite cheap.
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