# Matter and anti matter

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Classical mechanics says anti-matter is matter bur the electrons are orbiting the other way around the nucleus, which we now know with quantum mechanics that an electron doesn't actually physically orbit the nucleus, as far as we know, and since the direction of the spin of an electron doesn't change its charge either, what causes the creation of anti matter quantum mechanically, and what causes the charges to reverse?

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Classical mechanics says anti-matter is matter bur the electrons are orbiting the other way around the nucleus

It's a little more complicated than that.

You have to look at the time reversal, parity and charge symmetries.

http://www.lbl.gov/abc/wallchart/chapters/05/2.html

http://www.cem.msu.edu/~cem181fp/antimatter/antimatter.html

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An anti-particle, propagating forward in time, can be considered, as the corresponding particle, propagating backwards in time. Such is seen, quite commonly, in Feynman Diagrams ('back in time' arrows):

However, everyone, regardless of 'perceptual opinion', would regard 'the thing' (particle, time forward, to the left -or- antiparticle, time backwards, to the right) as having the same linear momentum (p = m x v 'to the left'). And, the anti-particle, is propagating in the opposite direction, through both time, and space ('to the right') -- yet, it still possesses, unambiguously, momentum 'to the left', to wit, 'backwards' against its own direction of propagation.

Thus, w.h.t.

$m_p \times v = p_{particle} \equiv p_{antiparticle} = m_{ap} \times -v$

$\therefore m_p \equiv -m_{ap}$

Er go, anti-matter, has anti-mass (which 'double reverses' its linear momentum, so that, moving 'to the right', albeit backwards in time, it still has momentum 'to the left') ??

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An anti-particle, propagating forward in time, can be considered, as the corresponding particle, propagating backwards in time. Such is seen, quite commonly, in Feynman Diagrams ('back in time' arrows):

However, everyone, regardless of 'perceptual opinion', would regard 'the thing' (particle, time forward, to the left -or- antiparticle, time backwards, to the right) as having the same linear momentum (p = m x v 'to the left'). And, the anti-particle, is propagating in the opposite direction, through both time, and space ('to the right') -- yet, it still possesses, unambiguously, momentum 'to the left', to wit, 'backwards' against its own direction of propagation.

Thus, w.h.t.

$m_p \times v = p_{particle} \equiv p_{antiparticle} = m_{ap} \times -v$

$\therefore m_p \equiv -m_{ap}$

Er go, anti-matter, has anti-mass (which 'double reverses' its linear momentum, so that, moving 'to the right', albeit backwards in time, it still has momentum 'to the left') ??

Eh, I don't know about that, because anti-matter still distorts the fabric of space in the same way. An anti-proton has the same or a similar mass/amount of material as a normal proton, and the electron configurations shouldn't really be different. I guess when you make something into anti matter, your making its waves peak and minimize at different moments with a different spin direction?

Also I have a question for Swan

In the diagrams of matter and anti-matter annihilation, like with a pair, it looks like this: e+ + e- = y + y. But in another topic, you had said that not matter or energy ever get converted into each other, and someone else said only their location or amount change, but from that equation, it would appear exactly as an anti-particle pair converted into gamma rays, with no left over mass, just energy. What's really going on? Is it just not mentioning some particles that were created?

Edited by steevey
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oops -- upon awaking, I realized, that velocity = change in distance / change in time. Thus, an anti-particle, moving 'to the left', but 'backwards in time', has a 'minus sign in the numerator & denominator'. And so, the 'double negative' means that it has the same velocity (not minus the velocity). In turn, such suggests, that anti-matter must, still, have normal mass (??).

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oops -- upon awaking, I realized, that velocity = change in distance / change in time. Thus, an anti-particle, moving 'to the left', but 'backwards in time', has a 'minus sign in the numerator & denominator'. And so, the 'double negative' means that it has the same velocity (not minus the velocity). In turn, such suggests, that anti-matter must, still, have normal mass (??).

That's the way I understand it, yes.

If you want to look for negative mass, you must insert negative distance. Both of which are totally counter intuitive and aphysical.

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In the diagrams of matter and anti-matter annihilation, like with a pair, it looks like this: e+ + e- = y + y. But in another topic, you had said that not matter or energy ever get converted into each other, and someone else said only their location or amount change, but from that equation, it would appear exactly as an anti-particle pair converted into gamma rays, with no left over mass, just energy. What's really going on? Is it just not mentioning some particles that were created?

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I guess its unanswerable, and not even the great Swan can answer it. Not even Stephen Hawking could answer it I bet.

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In the diagrams of matter and anti-matter annihilation, like with a pair, it looks like this: e+ + e- = y + y. But in another topic, you had said that not matter or energy ever get converted into each other, and someone else said only their location or amount change, but from that equation, it would appear exactly as an anti-particle pair converted into gamma rays, with no left over mass, just energy. What's really going on? Is it just not mentioning some particles that were created?

A particle and antiparticle annihilate and form photons. In the CoM frame of the e-e+ pair, assuming they're at rest, the energy of each photon is equal to $m_ec^2$

The mass of the particles is converted into electromagnetic energy. The net amount of matter is zero, because one particle is an antiparticle.

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A particle and antiparticle annihilate and form photons. In the CoM frame of the e-e+ pair, assuming they're at rest, the energy of each photon is equal to $m_ec^2$

The mass of the particles is converted into electromagnetic energy. The net amount of matter is zero, because one particle is an antiparticle.

But then that means matter is no longer matter, and energy is created, which I thought was impossible.

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But then that means matter is no longer matter,

Huh?

and energy is created, which I thought was impossible.

e+e- mass is converted to photon energy. Energy is not created.

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Huh?

e+e- mass is converted to photon energy. Energy is not created.

It means there's no longer matter in the coordinates that there are now photons, so where'd the matter go? Because I thought it couldn't be destroyed or be made into nothing/not matter. I tried asking you about this an another topic, and you said energy "doesn't" get converted into matter, and someone else or you said only the position change, so under that I would see how electrons contained energy within them then released it, but then there did the matter holding that energy go? Did it break down into simpler undetectable particles?

"

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Huh?

e+e- mass is converted to photon energy. Energy is not created.

It means there's no longer matter in the coordinates that there are now photons, so where'd the matter go? Because I thought it couldn't be destroyed or be made into nothing/not matter. I tried asking you about this an another topic, and you said energy "doesn't" get transformed into matter or vice versa, and someone else or you said only the position change, so under that I would see how electrons contained energy within them then released it, but then there did the matter holding that energy go? Did it break down into simpler undetectable particles?

It appears as though matter is disappearing and energy is reappearing in its place. Also, why would matter only convert into electro-magnetic waves? Why not gravitational waves or strong force waves or etc?

Edited by steevey
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Mass and matter are not the same thing. Mass is a property of matter

E=mc^2 — mass and energy are two versions of the same thing.

Thus, saying "matter is converted to energy" is nonsensical.

Mass is not a conserved quantity

Matter is not a conserved strictly quantity, either, though it requires parity violation (weak interaction) to turn antimatter into matter, so absent that, it is conserved

Antimatter is ANTI MATTER. The opposite of matter, if you will. If you have 1 part matter and 1 part antimatter, you have no net matter. They cancel. That's why it's termed "antimatter." e+e- annihilation involves zero net matter. Antimatter has mass, though, so the mass of the system is $2m_ec^2$, which is the amount of energy you have throughout the interaction. In this case you get photons because there is nothing else you can get — no particles with a smaller mass. If you annihilate e.g. protons and antiprotons (more massive) you can get other particles. Id you do collisions with a lot of kinetic energy (I have assumed everything at rest), that extra energy is also available.

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Mass and matter are not the same thing. Mass is a property of matter

E=mc^2 — mass and energy are two versions of the same thing.

Thus, saying "matter is converted to energy" is nonsensical.

Mass is not a conserved quantity

Matter is not a conserved strictly quantity, either, though it requires parity violation (weak interaction) to turn antimatter into matter, so absent that, it is conserved

Antimatter is ANTI MATTER. The opposite of matter, if you will. If you have 1 part matter and 1 part antimatter, you have no net matter. They cancel. That's why it's termed "antimatter." e+e- annihilation involves zero net matter. Antimatter has mass, though, so the mass of the system is $2m_ec^2$, which is the amount of energy you have throughout the interaction. In this case you get photons because there is nothing else you can get — no particles with a smaller mass. If you annihilate e.g. protons and antiprotons (more massive) you can get other particles. Id you do collisions with a lot of kinetic energy (I have assumed everything at rest), that extra energy is also available.

But then the electrons still cease to exist, as in matter disappears form reality and only energy is left, somehow. I see how mass mathematically is conserved, I just don't see how matter isn't ceasing to exist if electrons can't break down into smaller particles and they suddenly disappear, or at the very least, that they transform into energy.

Edited by steevey
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But then the electrons still cease to exist, as in matter disappears form reality and only energy is left, somehow. I see how mass mathematically is conserved, I just don't see how matter isn't ceasing to exist if electrons can't break down into smaller particles and they suddenly disappear, or at the very least, that they transform into energy.

ANTI = the opposite of. Antimatter is not matter. Bookkeeping-wise, because science is all about the math, a positron is -1 unit of (leptonic) matter, while an electron is +1 unit.

Mass isn't conserved

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ANTI = the opposite of. Antimatter is not matter. Bookkeeping-wise, because science is all about the math, a positron is -1 unit of (leptonic) matter, while an electron is +1 unit.

Mass isn't conserved

Anit-matter is just the same as matter, but has particles of opposite charge and spin. They both distort the fabric of space the same, I'm guessing they have the same orbital patterns, so its still matter or anti-matter ceasing to exist, or in other words, being destroyed, since all thats left over is energy, and mass is not conserved as you said. So I'm not seeing how this doesn't defy physics. Physics/chemistry states matter (or energy) cannot be created nor destroyed, yet there's matter-antimatter collisions and then virtual particles appearing our of the nothingness of space. Unless you can show me how matter and antimatter DON"T destroy each other as to cease to exist or this is actually whats happening, which case you could theoretically cause all matter in the universe to cease to exist by making anti matter equivalent to the mass of the normal matter.

Edited by steevey
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Physics/chemistry states matter (or energy) cannot be created nor destroyed,

No, it doesn't. The conservation law that does exist is energy, and one can interpret mass as being equivalent to energy through [imath]E=mc^2[/imath] and other well-known equations. Mass can be converted into energy and energy into mass just fine, and relativity gives you the tools to calculate how much mass gives how much energy.

Physics does not say that matter cannot be created or destroyed, because that is a false statement. Mass can be turned into energy. That's what atomic bombs do.

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(...) Mass can be turned into energy. (...)

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That can happen as well.

Anit-matter is just the same as matter, but has particles of opposite charge and spin. They both distort the fabric of space the same, I'm guessing they have the same orbital patterns, so its still matter or anti-matter ceasing to exist, or in other words, being destroyed, since all thats left over is energy, and mass is not conserved as you said. So I'm not seeing how this doesn't defy physics. Physics/chemistry states matter (or energy) cannot be created nor destroyed, yet there's matter-antimatter collisions and then virtual particles appearing our of the nothingness of space. Unless you can show me how matter and antimatter DON"T destroy each other as to cease to exist or this is actually whats happening, which case you could theoretically cause all matter in the universe to cease to exist by making anti matter equivalent to the mass of the normal matter.

Science is a bit like a jigsaw puzzle — the pieces fit together as long you aren't out on the edge still trying to figure it out. But you can't arbitrarily pick out some piece and discard it and put a different one back in its place and complain it doesn't fit. So you don't get to proclaim that matter cannot be created or destroyed, and you can't say that matter and antimatter are the same thing — that's not what the science says. When you get handed a piece that doesn't seem to fit, consider that you have gotten something wrong instead of the appeal to personal incredulity approach.

The bottom line is you could make the universe annihilate if you could make enough antimatter. But you can't make antimatter without making matter, too, and the rare instances where there is an imbalance it's from antimatter turning into matter rather than the other direction.

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Just in class today we were discussing an experiment in which two protons with a large kinetic energy were smashed together. Their kinetic energies were converted into a proton-antiproton pair, which has significant mass.

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That can happen as well.

Science is a bit like a jigsaw puzzle — the pieces fit together as long you aren't out on the edge still trying to figure it out. But you can't arbitrarily pick out some piece and discard it and put a different one back in its place and complain it doesn't fit. So you don't get to proclaim that matter cannot be created or destroyed, and you can't say that matter and antimatter are the same thing — that's not what the science says. When you get handed a piece that doesn't seem to fit, consider that you have gotten something wrong instead of the appeal to personal incredulity approach.

The bottom line is you could make the universe annihilate if you could make enough antimatter. But you can't make antimatter without making matter, too, and the rare instances where there is an imbalance it's from antimatter turning into matter rather than the other direction.

What definition are you using for matter ?

http://en.wikipedia.org/wiki/Matter

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What definition are you using for matter ?

http://en.wikipedia.org/wiki/Matter

We haven't gotten far enough that it's important. Matter isn't conserved under any of them, AFAIK.

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No, it doesn't. The conservation law that does exist is energy, and one can interpret mass as being equivalent to energy through [imath]E=mc^2[/imath] and other well-known equations. Mass can be converted into energy and energy into mass just fine, and relativity gives you the tools to calculate how much mass gives how much energy.

Physics does not say that matter cannot be created or destroyed, because that is a false statement. Mass can be turned into energy. That's what atomic bombs do.

So your saying mass can be turned into energy, but not that matter can be turned into energy? So if mass can be turned into energy, then both energy and matter must share something that gives mass, like a higgs boson or something which changes into something else in energy, only I don't know why light beams don't distort the fabric of space severely then.

Also, if matter can be created and destroyed just like that, whats wrong with thinking all matter in the universe just spontaneously came into existence of out shear improbability? And if matter can literally be destroyed and made not to exist, why hasn't anyone actually weaponized that?

Also when matter and antimatter combine, do they both cease to exist because the waves combined and equal 0?

Edited by steevey
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No, it doesn't. The conservation law that does exist is energy, and one can interpret mass as being equivalent to energy through [imath]E=mc^2[/imath] and other well-known equations. Mass can be converted into energy and energy into mass just fine, and relativity gives you the tools to calculate how much mass gives how much energy.

Physics does not say that matter cannot be created or destroyed, because that is a false statement. Mass can be turned into energy. That's what atomic bombs do.

Mass is not a conserved quantity
(from Swansont post #14)

We haven't gotten far enough that it's important. Matter isn't conserved under any of them, AFAIK.
(from Swansont post #23)

Even after Swanson's post #14, there is a confusion IMHO between matter & mass, beying used several times the one after the other in many posts. Or i am the one confused.

Clarification needed.

Edited by michel123456
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