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goodoldrebel
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Without using ' opposite charges of matter' explanation as a foundation for defining anti-matter, I wonder if anyone can present a more direct definition and examples.
Vorde said:What troubles you about that explanation?
mathman said:Be careful about using opposite charge. Neutrons and other neutral particles have anti-particles (anti-neutrons, etc.).
Bobbywhy said:goodoldrebel, here are three websites you may visit to read about what is anti-matter.
Included find direct definitions and examples in concrete terms.
http://www.lbl.gov/abc/Antimatter.html
http://en.wikipedia.org/wiki/Antimatter
http://livefromcern.web.cern.ch/livefromcern/antimatter/
goodoldrebel said:very good sights, yet antimatter is still an elusive concept.
Nabeshin said:Here's my problem with what you're saying about why you don't like the 'opposite' definition of antimatter. If you imagine WE had instead been made of antimatter, then the other stuff would be antimatter and you would be complaining you cannot explain that! It's like trying to define what an electron is without saying "Mass 511KeV, spin 1/2 and charge -1". That's WHAT it is. Similarly, what any particular antiparticle is is simply a list of all such numbers, but with charge reversed. (Note: Someone already pointed to the neutron, which is not the same as its antiparticle. This is of course because the neutron is not a fundamental particle, but rather composed of three quarks.) At this point I think it degenerates into the same discussion that was had here about what an electron REALLY is, which I'm sure you can find.
I disagree, it ignores the theoretical construction that relates particles to each other. And saying the electron and the positron have the same mass, spin and opposite charge, does not tell you that upon contact they annihilate. So there is something more at work. A more illuminating answer might involve how theoretically antimatter can be deduced from matter, but I won't try to do that here as I'm not familiar enough with the material myself.Nabeshin said:Here's my problem with what you're saying about why you don't like the 'opposite' definition of antimatter. If you imagine WE had instead been made of antimatter, then the other stuff would be antimatter and you would be complaining you cannot explain that! It's like trying to define what an electron is without saying "Mass 511KeV, spin 1/2 and charge -1". That's WHAT it is. Similarly, what any particular antiparticle is is simply a list of all such numbers, but with charge reversed. (Note: Someone already pointed to the neutron, which is not the same as its antiparticle. This is of course because the neutron is not a fundamental particle, but rather composed of three quarks.) At this point I think it degenerates into the same discussion that was had here about what an electron REALLY is, which I'm sure you can find.
That would be a really good argument. Except, neutrinos are neutral, and neutrino and anti-neutrino are not the same particle. So even for elementary particles, simply saying that difference between particle and anti-particle is charge is false.Nabeshin said:Here's my problem with what you're saying about why you don't like the 'opposite' definition of antimatter. If you imagine WE had instead been made of antimatter, then the other stuff would be antimatter and you would be complaining you cannot explain that! It's like trying to define what an electron is without saying "Mass 511KeV, spin 1/2 and charge -1". That's WHAT it is. Similarly, what any particular antiparticle is is simply a list of all such numbers, but with charge reversed. (Note: Someone already pointed to the neutron, which is not the same as its antiparticle. This is of course because the neutron is not a fundamental particle, but rather composed of three quarks.) At this point I think it degenerates into the same discussion that was had here about what an electron REALLY is, which I'm sure you can find.
K^2 said:That would be a really good argument. Except, neutrinos are neutral, and neutrino and anti-neutrino are not the same particle. So even for elementary particles, simply saying that difference between particle and anti-particle is charge is false.
mr. vodka said:I disagree, it ignores the theoretical construction that relates particles to each other. And saying the electron and the positron have the same mass, spin and opposite charge, does not tell you that upon contact they annihilate. So there is something more at work. A more illuminating answer might involve how theoretically antimatter can be deduced from matter, but I won't try to do that here as I'm not familiar enough with the material myself.
Nabeshin said:I was under the impression the existence of majorana fermions was still an open question?
Yes, but neutrino being such is extremely unlikely. There should be some experiments in the near future to determine it with better certainty, but the standard model assumes them to be Dirac fermions, and there seem to be no contradictions due to that. There are a whole bunch of weak interactions and decays whose cross-sections would be off if neutrinos were their own anti-particles.Nabeshin said:I was under the impression the existence of majorana fermions was still an open question?
Anti-matter is a type of matter that is made up of particles with the same mass as ordinary matter, but with opposite charges. This means that anti-matter particles have a negative charge, while ordinary matter particles have a positive charge.
Aside from the opposite charges of its particles, anti-matter also has the opposite magnetic properties of ordinary matter. This means that anti-matter particles will repel each other, while ordinary matter particles will attract each other.
Anti-matter is created in high-energy environments, such as during the collision of particles in particle accelerators. It can also be found in small amounts in some natural processes, such as radioactive decay.
Anti-matter has many potential applications in fields such as medicine, energy production, and space travel. For example, anti-matter could be used in medical imaging to produce clearer images, or in spacecraft propulsion systems to achieve faster speeds.
In small amounts, anti-matter is not dangerous. However, if a large amount of anti-matter were to come into contact with ordinary matter, it would result in a powerful explosion. Scientists are still researching ways to safely contain and use anti-matter for practical applications.