What is Anti-matter: Definition and 81 Discussions

In modern physics, antimatter is defined as matter that is composed of the antiparticles (or "partners") of the corresponding particles of "ordinary" matter. Minuscule numbers of antiparticles are generated daily at particle accelerators—total production has been only a few nanograms (ng)—and in natural processes like cosmic ray collisions and some types of radioactive decay, but only a tiny fraction of these have successfully been bound together in experiments to form anti-atoms. No macroscopic amount of antimatter has ever been assembled due to the extreme cost and difficulty of production and handling.
Theoretically, a particle and its anti-particle (for example, a proton and an antiproton) have the same mass, but opposite electric charge, and other differences in quantum numbers. For example, a proton has positive charge while an antiproton has negative charge.
A collision between any particle and its anti-particle partner leads to their mutual annihilation, giving rise to various proportions of intense photons (gamma rays), neutrinos, and sometimes less-massive particle–antiparticle pairs. The majority of the total energy of annihilation emerges in the form of ionizing radiation. If surrounding matter is present, the energy content of this radiation will be absorbed and converted into other forms of energy, such as heat or light. The amount of energy released is usually proportional to the total mass of the collided matter and antimatter, in accordance with the notable mass–energy equivalence equation, E=mc2.Antimatter particles bind with each other to form antimatter, just as ordinary particles bind to form normal matter. For example, a positron (the antiparticle of the electron) and an antiproton (the antiparticle of the proton) can form an antihydrogen atom. The nuclei of antihelium have been artificially produced, albeit with difficulty, and are the most complex anti-nuclei so far observed. Physical principles indicate that complex antimatter atomic nuclei are possible, as well as anti-atoms corresponding to the known chemical elements.
There is strong evidence that the observable universe is composed almost entirely of ordinary matter, as opposed to an equal mixture of matter and antimatter. This asymmetry of matter and antimatter in the visible universe is one of the great unsolved problems in physics. The process by which this inequality between matter and antimatter particles developed is called baryogenesis.

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  1. A

    B The nature of anti-particles and anti-matter (a dilettante asks)

    Do particles and anti-particles have gravitational force between them? If they are made of matter, both of them, what is the reason one particle is regular, and the other is a counter-particle? Or anti-particle? I am confused by the naming. Anti- means against, opposite, counter-. A matter has...
  2. H

    B Is there any kind of anti-matter "problem"?

    I watched a youtube pop-sci program the other day where the host kept talking about there being some anti-matter "problem". Sabine Hossenfelder, Lee Smolin, and at least one other kept trying to tell him there was no problem, but he never seemed to grasp what they were saying. The alleged...
  3. danielhaish

    I Why is it that when anti-matter and matter meet they produce energy?

    I understand that the mass is being converted to energy but isn't it just an destructive interference of the properties of particles being present as waves of possibility , for example when electron is Interference with it self is it produce energy?, because the particle are weaves in quantum...
  4. A

    B Anti-matter discovery before 1932?

    I once heard that anti-matter has been observed long before 1932 (the year of its official discovery) in cloud chamber tracks but was not recognized as such. If I remember well it frequently appeared in the photographs of cloud chambers with its characteristic pair production phenomenon but it...
  5. F

    B Anti-matter and matter annihilation

    Does anti-matter and matter annihilate each other even if they are not same "type" (eg. neutron and positron) and they meet each other?
  6. A

    I Exploring the Slight Preponderance of Matter Over Anti-Matter

    I have seen the term "slight preponderance" used many times to account for the apparent imbalance of matter and antimatter. I am not aware of the scientific justification for this however. Indeed, I have recently watched a lecture where, again, it is stated that we live in a matter universe. How...
  7. S

    I Matter predominates b/c anti-matter fell into black holes?

    I was reading an article about the great Steven Hawking, and it seems to say that matter & anti-matter can be created in space, but that one of them can fall into a black hole, thus leaving the other around in a higher preponderance, which of course matter is. So it would seem that a good...
  8. marce

    B Big bang and matter anti-matter inbalance

    - I never quite understood , while people generally believe they must search for the reason of matter, anti-matter unbalance. I mean the big-bang was a violation of the energy conservation law. As far as I understand in the first moment there was only energy which later condensed into matter and...
  9. A

    Can an Anti-Matter Blade Cut Through Anything?

    I recently got this weird idea of a blade which would work not with matter but with anti-matter. The idea is that an anti-particle (anti-proton, anti-neutron, anti-electron) generator would create a "spray" of antimatter towards a specific direction. Said antimatter would interact and "puff out...
  10. L

    I Dark Matter: Can Gravitational Field Be Generated?

    The dark matter is described as something which can't be detected in any way except for its gravitational attraction. My question is: may the dark matter be identified with gravitational field generated by the presence (for short times) of matter and anti-matter which is continually created and...
  11. S

    What Happens When a Street Urchin Walks Into the Higgs Boson Analogy?

    i was thinking about the Higgs Boson analogy that was put forward to help describe how it works/interacts to produce mass, of a very famous person walking into a party, everyone gathers round impedes progress, high interaction with Higgs field and particles therefore high mass, and then a less...
  12. rmoh13

    Is this a possible idea for an antimatter rocket engine?

    Antimatter can be contained in magnetic fields; what if we could somehow "propel" that magnetic field by using a magnetic nozzle when the small antimatter-matter reactions/annihilation occurs which produces thrust? This seems like a really stupid idea, but can you tell me some limitations about...
  13. H

    Anti-matter annihilation and the CMBR

    Recently I watched a lecture on Anti-matter and the Standard Model... ...At one point Dr. Quinn, makes the statement that the CMB is the resulting energy left over from the annihilation of the matter and anti-matter which arose during cosmic inflation (leaving behind only one part in 30 million...
  14. S

    Generating anti-matter through neutrinos

    I've seen a few articles that describe neutrino interactions creating anti-particles and that those neutrinos are originating from deep space nuclear reactions. Could neutrinos from a fusion reactor be harvested/used to generate anti-hydrogen? Maybe by circulating protons around a fusion reactor.
  15. xortdsc

    Is there a reason to believe there is more matter than anti-matter ?

    Hi, I keep reading about that the universe is supposed to be composed of only matter. And that this matter was an excess amount compared to anti-matter after the big bang. So most of the matter and anti-matter annihilated each other and some matter was left over. My question is: What is...
  16. shounakbhatta

    Matter vs Anti-Matter: What Survived the Big Bang?

    If equal amount of matter and anti-matter was created during the Big Bang, what is existing now? Matter? Thanks.
  17. M

    Anti-matter Creation Questions/ Discussion

    Hello everyone! I would first like to say that I am not exactly unfamiliar with these forums; I'm one of those people who is like a... "long -time thread watcher, first time poster." So yes, this is my first post. :smile: I have used these forums as a sort of reference library, looking up...
  18. S

    Dirac's equation and anti-matter

    Can someone explain how Dirac was able to deduce that anti-matter exists? How did this follow naturally from Dirac's equation? Did Dirac have to derive his equation or was it just an empirical law of nature like Newton's gravity or Einstein's Field equations?
  19. DEvens

    Anti-Matter Falling Speed - Experiments & Results

    Has the experiment been done to drop anti-matter and see if it falls the same speed as regular matter? I seem to have a memory of an experiment to drop anti-protons from quite some time ago. But I don't seem to find a reference when I look.
  20. chasrob

    Can We Make Contact with an Anti-Matter Black Hole?

    Is there any such thing? Or is it unphysical? If it's physical, would making contact with a matter black hole result in E=mc^2? Thanks.
  21. S

    Creating an Anti-Matter Machine at Home

    Hi, I am an Australian High School student who enjoys studying mathematical and scientific phenomena. It is a mandatory requirement of all students my age that next year we complete a Personal Research Project. The project is designed in a way that allows students to pick their desired area of...
  22. A

    Can We Identify Anti-Matter Galaxies?

    As far as I know, matter and anti-matter are only different in charge and spin. Therefore a star undergoing fusion reactions with anti-matter should give off the same light spectrum we see with fusion reactions in a star comprised of matter, so it would show the same absorption lines. Would...
  23. Low-Q

    When matter and anti-matter = explosion or not

    I have been told, and it has been written that matter and anti-matter destroys each other if they happen to bump into each other. The destruction is told to generate an energy burst beyond imaginary scales. What I have a doubt about is this: If energy that is dense enough can produce elementary...
  24. H

    Can anti-matter create anti-gravity and is it related to photon pairing?

    As the positron has a positive charge and is the mirror of the electron and the antiproton is negative and a mirror of the proton, will then anti-matter produce anti-gravity. If not then why not? Is this linked to the photon pairing of electron and positron?
  25. F

    MHB Question about anti-matter colliding with matter

    I was watching this YouTube video regarding the formation of our universe (around 20:09 minutes) and they were talking about antimatter and matter. When anti matter comes into contact with normal matter they obliterate each other and a large amount of energy is released. When our universe was...
  26. D

    Can Anti-Photons Exist in Our Universe and How Do They Behave?

    Granted its not cost effective to produce anti-matter in great amounts; however if one where to apply energy to matter, eventually that matter will release a photon or light. I can't find any information where its not the same with anti-matter. So assuming one can excite anti-matter to give...
  27. K

    When anti-matter and matter collide are they destroyed?

    When anti-matter and matter collide , they say they both annihilate however isn't it known according to the law of conservation that matter can't be created nor destroyed. This confuses me.
  28. C

    Assumption that Anti-Matter Galaxies Would Emit Detectable Gamma Ray Bursts

    In the hunt for antimatter galaxies, the tools that we are currently using look for gamma rays that would be emitted due to annihilation events, because everything else about these galaxies is predicted to be the same emission-wise. The hypothesis is that these annihilation events would occur...
  29. D

    Is Casamir Effect Related to Anti-Matter?

    I have been reading round the Casamir Effect and Diracs vacuum field. On the one hand it appears to be a straightforward classical Van Der Waals forces concept related to capillary action and surface tension (duh), on the other hand I read that the Casamir effect is a possible method to...
  30. G

    Can anyone define anti-matter in concrete terms?

    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.
  31. F

    How can the Chi_b (3P) particle exist if matter and anti-matter annihilate?

    The recently discovered Chi_b (3P) is made up of a bottom quark and an anti bottom quark. I thought, however, that should a matter particle meet with its anti counterpart, they would annihilate into pure energy. Am I missing something? Thanks.
  32. khurram usman

    Can anti-matter be stored in super conducting magnetic cylinders?

    frankly i don't know much about anti-matter or super conductors...i just read an into-level topic on anti-matter and had a thought. the main concern while developing an energy source is that its feasibility should be considered...right? and the problem with anti-matter is that it takes too much...
  33. S

    Where did the inertia go in anti-matter reaction?

    This question is about momentum in a system when an electron and positron annihilate each other. Consider the following, please: SITUATION Consider a system of 3 particles. They are in motion (which I will explain with Earth as the geometric frame). The electron (#1) is moving, coming from...
  34. H

    Anti-matter vs matter at creation.

    During the creation of the universe, aka the big bang, it is recognised that matter was in a greater supply then anti-matter. The reason for this is unknown. So we are able to create anti-matter at great expense, have we ever tried to make anti-matter into matter? Because if the method...
  35. A

    Trapping Anti-Matter: Difficulties & Quantum Fluctuations

    Y is trapping anti-matter so difficult...if we create a vacuum and trap the particles via magnetic field y will it still annihilate?? are quantum fluctuations in vacuum responsible for it??
  36. E

    Protons: matter or anti-matter?

    Electron is annihilated by positron. Proton is annihilated by anti-proton. But neither proton, nor anti-proton annihilate electron (or positron). If we assume that electron relates to matter, how do we know what is matter and what is antimatter: proton or anti-proton? What if protons relate to...
  37. J

    When matter and anti-matter collide, in what form is the resulting energy?

    I know that when matter is mixed with anti matter they disappear into pure energy. But how can there be energy with no matter? Is it light that forms? do we get a massive blast of light? what else could it be? with no matter you can't have energy(exept for light)... what happens?
  38. T

    What happened to all the Anti-Matter

    I recall that the absence of Anti Matter used to be a concern to Cosmologists, has this situation changed in recent years perhaps with the discovery of a slight assymetry between the two? What is the current understanding?
  39. J

    How do the wave-functions of particles and anti-particles differ?

    How does the wave-function of a particle differ from its anti-particle counterpart? Are they out of phase from each other? How could we tell, by looking at their wave-functions, the difference between an electron and a positron?
  40. J

    What are the properties of anti-matter?

    What are the properties of anti-matter? Does anti-matter have anti-mass? Since there is anti-matter, is there also anti-energy? Is anti-matter subject to anti-gravity? Can particles with no anti- counterpart be considered as matter?
  41. J

    Surplus of matter over anti-matter

    I'm wondering why I haven't run into a discussion anywhere that uses Feynman's model of anti-matter moving backward in time to explain the paucity of anti-matter in our universe. Quite simply: The big bang created equal quantities of matter and anti matter. Almost all that was...
  42. Q

    Does anti-matter Always annihilate with matter?

    So there seems to be an issue concerning the annihilation of an electron and a positron given the following scenario: Say an electron has spin +1/2 or up, (say Z-axis is up) and a positron has spin +1/2 or up as well. Now... I know that a photon has to be a spin of 1. (This is important...
  43. Z

    Exploring Anti-Matter: Why Aren't Atoms Composed of Positrons & Antiprotons?

    I've recently learned more about antimatter, namely what types there are, and one question has stuck in my mind: why are atoms not composed of Positrons and Antiprotons? Since scientists at the LHC recently were able to contain antihydrogen, it seems that these atoms, while isolated from matter...
  44. A

    Atoms of anti-matter trapped for first time.

    Anti-hydrogen atoms have been trapped/stored for the first time at CERN. http://newscenter.lbl.gov/news-releases/2010/11/17/antimatter-atoms/
  45. L

    Could an antimatter alien's arrival on Earth cause a global explosion?

    Somebody told your friend that if an antimatter alien ever set foot upon Earth, the whole world would explode into pure radiant energy. Your friend looks to you for verification or refutation of this claim. What do you say? N/A I am confused at this question Seems simple but I am...
  46. D

    Exploring the Possibility of Anti-Matter Moving Backwards Through Time

    Hi i was just thinking today and don't know enough to be able to rubbish my own theories. I was thinking about the start of the universe being a singularity, and the plotted curve of 1/x having the 2 solutions , positive and negative infinity at its y axis. It led me to wonder whether...
  47. Q

    Spin, Anti-matter and all that jazz.

    Hello, Can someone explain to me- in a conceptual manner- why when Special Relativity and QM are combined (ie Dirac) anti-matter and spin naturally come out? I have seen and understand the mathematics, but I am looking for a more physical explanation. Thanks
  48. R

    Is the world of anti-matter a possibility or just a fictional concept?

    The world of anti-matter sounds like something only for fiction stories because scientific professionals seem to have not found enough reason to believe it yet. I in fact is not a professional in physics (I am a philosopher) but I like to read physics. I see the world of anti-matter to be quite...
  49. M

    Matter & Anti-Matter: Why Do Particles Group in Matter?

    Is there any fundamental principle that explains why, for example, (up q, down q, and electron) are in the same group which we "happened" to call "matter", but not say (up q, down q, and positron)? Because in the latter case, the world would consists of proton, neutron, and position and atoms...
  50. C

    Hawking Radiation & Parity Imbalance: Matter vs. Anti-Matter

    Does Hawking radiation account for the parity imbalance between matter and anti-matter? Do Black Holes create matter? If a matter/anti-matter pair materializes on either side of the event horizon of a black hole: 1) if the matter particle is on the inside of the event horizon, the mass of the...