Antimatter + Matter = ?

[Blizzard Six]

I've just started reading about the basics of quantum physics, and I have a question. I've always heard two things:

1. Matter cannot be created or destroyed.
2. Matter and antimatter cancel each other out.

My question concerns #2. What exactly, in layman's terms, happens when antimatter and matter meet? I've heard something like a bright flash of light happens, but what happens to the matter/antimatter? I assume it's not destroyed (in agreement with #1), just converted into something else. What is it though? Thanks to anyone who knows.

[Cataclysm]

Matter + Antimatter = Energy.

Since its possible to turn matter into energy, I wonder if it would be possible to turn energy into matter?

[H_man]

Matter + Antimatter = Energy.

Since its possible to turn matter into energy, I wonder if it would be possible to turn energy into matter?

The beginning of the universe saw pure energy transforming into matter.

[Holger Danske]

Matter + Antimatter = Massive amounts of energy.

Fixed.

[Chaigidel]

all of the mass is converted into energy-- I think -- heat/radiation etc

[H_man]

Although I am, as of yet, NOT a physics expert, I believe I can shed *some*, if only partially correct light into your query. When a matter-antimatter reaction occurs, the particles become neutralized (opposite charge) and emit pure energy being exerted at the speed of light. I believe that this is no longer considered matter, in the conventional sense, but is merely the conversion of matter into energy, which, although it goes against the law of conservation of mass, ala Antoine Lavoisier, it is completely consistent with Einstein's famous equation, E=mc^2.

[Blizzard Six]

Although I am, as of yet, NOT a physics expert, I believe I can shed *some*, if only partially correct light into your query. When a matter-antimatter reaction occurs, the particles become neutralized (opposite charge) and emit pure energy being exerted at the speed of light. I believe that this is no longer considered matter, in the conventional sense, but is merely the conversion of matter into energy, which, although it goes against the law of conservation of mass, ala Antoine Lavoisier, it is completely consistent with Einstein's famous equation, E=mc^2.

I had a sneaking suspicion that's what happened. Thanks for clearing it up guys.

[H_man]

I had a sneaking suspicion that's what happened. Thanks for clearing it up guys.

If you would like to learn more about antimatter, go to: http://www.lbl.gov/abc/Antimatter.html or your local librabry. PBS is paid for in part by viewers like you. Thank you.

A particle and its antimatter particle annihilate when they meet: they disappear and their kinetic plus rest-mass energy is converted into other particles (E = mc2). For example, when an electron and a positron annihilate at rest, two gamma rays, each with energy 511 keV, are produced. These gamma rays go off in opposite directions because both energy and momentum must be conserved. The annihilation of positrons and electrons is the basis of Positron Emission Tomography (PET) discussed in the section on Applications (Chapter 14). When a proton and an antiproton annihilate at rest, other particles are usually produced, but the total kinetic plus rest mass energies of these products adds up to twice the rest mass energy of the proton (2 x 938 MeV).

[Trax]

1. Matter energy cannot be created or destroyed.

matter=energy

[Simetrical]

Since its possible to turn matter into energy, I wonder if it would be possible to turn energy into matter?

Of course it is. This is what happens all the time at particle accelerators: massive amounts of kinetic energy (at least, massive on a particle level; less than that of, say, a person walking) are imparted to particles, which collide and create an array of other particles. That's the point of particle accelerators, in fact.

Although I am, as of yet, NOT a physics expert, I believe I can shed *some*, if only partially correct light into your query. When a matter-antimatter reaction occurs, the particles become neutralized (opposite charge) and emit pure energy being exerted at the speed of light. I believe that this is no longer considered matter, in the conventional sense, but is merely the conversion of matter into energy, which, although it goes against the law of conservation of mass, ala Antoine Lavoisier, it is completely consistent with Einstein's famous equation, E=mc^2.

Yes, this is right. The matter gets converted into energy, which is permitted in relativity (since mass is just rest energy). The most commonly-mentioned case is electron-positron annihilation, which produces two photons traveling in opposite directions, with the same amount of energy and momentum as the electron-positron pair had. Photons are massless and so are not considered matter, but energy is conserved.

[Cataclysm]

Of course it is. This is what happens all the time at particle accelerators: massive amounts of kinetic energy (at least, massive on a particle level; less than that of, say, a person walking) are imparted to particles, which collide and create an array of other particles. That's the point of particle accelerators, in fact.

I never knew they actually converted energy into matter, I thought they smashed things together so hard it rearranged and merged the subatomic particles to create new ones. This is fascinating, I wonder if we'll ever be able to harness that technology to produce any substantial amount of matter

[Aetius]

I've just started reading about the basics of quantum physics, and I have a question. I've always heard two things:

1. Matter cannot be created or destroyed.
2. Matter and antimatter cancel each other out.

My question concerns #2. What exactly, in layman's terms, happens when antimatter and matter meet?

It has been theorized that this technology would be the ultimate advance in bomb technology. A mix of the two will result in an ENORMUS amount of energy, surely enough to destroy the solar system...

I hope to god that is never invented...

[H_man]

It has been theorized that this technology would be the ultimate advance in bomb technology. A mix of the two will result in an ENORMUS amount of energy, surely enough to destroy the solar system...

I hope to god that is never invented...

To quote Wikipedia:

Antimatter is said to be the most expensive substance in existence, with an estimated cost of $300 billion per milligram. This is because production is difficult (only a few atoms are produced in reactions in particle accelerators), and because there is higher demand for the other uses of particle accelerators. According to CERN, it has cost a few hundred million Swiss Francs to produce about 1 billionth of a gram.[10]

[Simetrical]

It has been theorized that this technology would be the ultimate advance in bomb technology. A mix of the two will result in an ENORMUS amount of energy, surely enough to destroy the solar system...

I hope to god that is never invented...

It has been. It's just so expensive as to be worthless as a weapon. It's also really not very destructive, as these things go: antimatter annihilation releases enormous amounts of energy, but all as gamma rays. It would kill anyone in line-of-sight of the blast, but wouldn't damage buildings or other infrastructure at all. Gamma rays don't reflect very well off the atmosphere or anything else, and don't penetrate remarkably far through dirt. Nuclear weapons are likely to be far more effective as well as vastly cheaper.

[Ulf]

It has been. It's just so expensive as to be worthless as a weapon. It's also really not very destructive, as these things go: antimatter annihilation releases enormous amounts of energy, but all as gamma rays. It would kill anyone in line-of-sight of the blast, but wouldn't damage buildings or other infrastructure at all. Gamma rays don't reflect very well off the atmosphere or anything else, and don't penetrate remarkably far through dirt. Nuclear weapons are likely to be far more effective as well as vastly cheaper.

you have a frightful amount of knowledge concerning advanced weaponry and "doomsday devices".

but yes, Anitmatter+matter=energy

[Oberbefehlshaber]

Simply put, antimatter is a fundamental particle of regular matter with its electrical charge reversed. The common proton has an antimatter counterpart called the antiproton. It has the same mass but an opposite charge.

Antimatter has tremendous energy potential, if it could ever be harnessed. A solar flare in July 2002 created about a pound of antimatter, according to new NASA research. That's enough to power the United States for two days.

[johnny5000]

It would kill anyone in line-of-sight of the blast, but wouldn't damage buildings or other infrastructure at all.

Isn't that the idea of the neutron bomb? Reduce damage to infrastructure?

[Simetrical]

Simply put, antimatter is a fundamental particle of regular matter with its electrical charge reversed. The common proton has an antimatter counterpart called the antiproton. It has the same mass but an opposite charge.

True for fundamental particles, but to nitpick, not true for particles that are composed of other particles. There's such a thing as an antineutron, for instance. It doesn't differ in charge from a neutron, but it's make up of antiquarks, whose charges differ from the charges making up a neutron. So a fundamental antiparticle is a normal particle with reversed charge but the same mass, and an antiparticle is something composed of fundamental antiparticles.

I never knew they actually converted energy into matter, I thought they smashed things together so hard it rearranged and merged the subatomic particles to create new ones. This is fascinating, I wonder if we'll ever be able to harness that technology to produce any substantial amount of matter

We can already, but it's ridiculously expensive.

Isn't that the idea of the neutron bomb? Reduce damage to infrastructure?

True. The neutron bomb, however, is a lot cheaper.

[Redem]

I've just started reading about the basics of quantum physics, and I have a question. I've always heard two things:

1. Matter cannot be created or destroyed.
2. Matter and antimatter cancel each other out.

My question concerns #2. What exactly, in layman's terms, happens when antimatter and matter meet? I've heard something like a bright flash of light happens, but what happens to the matter/antimatter? I assume it's not destroyed (in agreement with #1), just converted into something else. What is it though? Thanks to anyone who knows.

Been covered in some detail, but anyway.

The problem is 1. There is a law of conservation of matter used in chemistry, it's basically that no matter is lost via simple chemical reactions.

There is also a law of conservation of energy, in physics, which states that energy cannot be created or destroyed, merely changed from one form to another.
Matter, being a form of energy, is covered by this law, in terms of matter-antimatter annihilation reactions.

When the two meet, they annihilate each other and release their combined mass in energy. Broadly E=mc^2 covers the released energy.


Predictably, when people learn of it they consider it's use as a weapon. A couple of problems, it's pointless when we can get better energy release from more mundane sources. It's ridiculously costly to make antimatter. And it's impossible to contain it in any useful form for use in a weapon, yet.


Another thing someone raised, was wondering if it was reversible. Technically, kinda, yes. At high energy densities matter forms, that's one of the things that is explored in particle colliders, such as the newly finished Large Hadron Collider at CERN.

[Simetrical]

And it's impossible to contain it in any useful form for use in a weapon, yet.

Uniformly charged antimatter (i.e., either all positive or all negative) can be straightforwardly contained in a magnetic field. There was a press release/essay/something like that I read by a NASA employee explaining how NASA was considering antimatter as a fuel source for a Mars mission, in fact.