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Could this be an explanation why there is more matter than antimatter?

  1. May 4, 2010 #1
    There is an old weird theory that an antiparticle is actually a particle going back in time; when a pair is born "out of nowhere", it's in fact one particle making a U-turn in time.

    Now, consider the expanding Universe. Let's say you are observing a nearby spinning galaxy drifting away from you because of the expansion. Most part of the matter moves away, while some part of the matter due to spinning moves towards you. This holds true even if you take only one dimension out of the 3.

    Because time is just another dimension, let's assume most of the matter is moving in one direction, just like matter in 3D space, and only some part of it due to local spinning effects or whatever else, can sometimes move backwards. That's antimatter and this is why it's scarce. So the Universe is expanding in all 4 dimensions, and antimatter may be a good proof of that.

    (I have no idea if this makes any sense at all, but it came a few days ago when I was about to fall asleep, actually half-dreaming already, when suddenly this idea broke into my head. It happens.)
  2. jcsd
  3. May 4, 2010 #2
    Huh...man, it makes no sense. BTW universe is expanding only in 3 spatial dimensions.
  4. May 4, 2010 #3
  5. May 4, 2010 #4


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    Yeah, this makes no sense. This isn't even an attempted explanation of why there is a matter/antimatter asymmetry. You simply assume most of the matter is moving in the positive timelike direction (matter) and only a small portion is moving backwards (antimatter), which is exactly analogous to assuming there is an abundance of matter over antimatter. You cannot assume that which you are trying to explain!

    The essential flavour of the problem is as follows: When particles are produced out of pure energy, they are always produced in matter-antimatter pairs, in even portions. The consensus is that when the universe was hot and young there was enough energy to be constantly producing these pairs of particles. How then did it come to be, if they are supposedly produced in equal amounts, that there is such an overwhelming abundance of one over the other?

    Make sense?
  6. May 5, 2010 #5
    How do you know we are not the anitmater and that it's the matter that is rare?
    Actually I kind of grasp what the OP is asking. He is saying there is only one kind of matter. And that matter moves away from us in time just like it does in the other 3 dimensions due to expansion. That idea doesn't hold up though. In that case we would see distant galaxies as matter and we would see lots of antimatter nearby since expansion doesn't have much local effect.

    I wouldn't call it weird. The idea is a result of the Feinman diagram. An antimatter particle can be viewed as a normal matter particle traveling backwards in time.

    so question 1:
    Since a particle / antiparticle anihilation releasing energy could also be viewed as two particles being created from a high energy state and one flying off in one direction in time and the other flying off in the opposite direction in time, would it be likely that we would only see one kind of matter and not the other because we experience time in only one direction?

    and question 2:
    What is the real reason for the lack of antimatter? Does anyone know?
    Last edited: May 5, 2010
  7. May 5, 2010 #6


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    Again, no. We know that pair production is just that -- particles are produced in pairs of matter and antimatter. In the generally understood sense (I might be leaving out fairly recent or far out explanations), we observe matter and antimatter to be produced in exactly equal proportions.
    This is still a very open question. If, at the very beginning of the universe there was 1 part in a billion extra matter over antimatter, then the current asymmetry could be explained. How to get that initial 1 part in a billion is tricky, though.
  8. May 5, 2010 #7
    I don't think this is a correct statement: "one flying off in one direction in time and the other flying off in the opposite direction in time" - we are talking about one particle making a U-turn in time, and because we experience time in only one direction, the phenomenon appears to us as birth of a pair. But anyway, I think the fact that we are able to detect antiparticles we may assume we have no problem with seeing antimatter; thus the question of why there is more matter is still open.

    We may also leave a purely theoretical possibility that there is equal amount of anti/ and matter, but detection of antimatter is hindered by some unknown time-related physical phenomenon, e.g. we only "see" them shortly before and after the U-turn.

    Curiously, better understanding of the birth and annihilation of pairs accompanied by energy may shed some light on the nature of energy. Think about it: one particle is making a U-turn in time, but what we see at the moment of the turn from our perspective is transformation of energy. Energy may have a different meaning if we look at it "from outside time".
  9. May 5, 2010 #8
    It is purely convention which you choose to call antimatter and which you call normal matter. Neither of them is special, other than the fact that one type is rare (the point of the paradox).
  10. May 6, 2010 #9
    This is nothing to do with real physics or cosmology, this is speculating and wishful thinking. It's hard to respond to something that is only in your imagination. Matter/Anti-Matter asymmetry is unexplained, and none of the serious candidates are even close to this "U turn".
  11. May 7, 2010 #10
    You have it wrong , the universe is not expanding infact it is moving in a spatial three dimensional way. The fact of the matter ( pun intended) is that there is no antimatter in the universe due to the matter/antimatter annihalation reaction, which causes all of the matter/antimatter involved to be destoryed. Theories for the creation of the universal matter that we know are the big bang theory and the god theory, however i have a theory of my own. I have named it the product theory, it involves einsteins E=MC2, the energy produced from the reaction would have to produce mass if this equation is correct. I theorise that it is possible,, that our galaxy, the universe in fact, is a matter product of the energy produced from the original matter/antimatter reaction of the big bang.
  12. May 8, 2010 #11
    well it's not make sense at all. in past matter and antimatter were created from pure energy and the expansion rate of universe is too much for annihilation to occur and matter is taken away from antimatter.
    This point is also appreciated by Stephen Hawking.
    But the real question is how we can see one thing but not it's anti.
    i will write soon on this.
  13. May 10, 2010 #12
    How do we know there's more matter than antimatter in the universe?
  14. May 10, 2010 #13
    Observed universe does not show gamma rays from annihilation.
  15. May 10, 2010 #14
    Thanks, Iced, I didn't know that.

    For me, that makes the question "why does the observed universe not show gamma rays from annihilation", with one hypothesis being that it's overwhelmingly matter, and another being that the vacuum between galaxies is so rarefied that there would be very few gamma rays.

    That second hypothesis has no doubt been addressed. But I guess that's material for another thread.
  16. May 24, 2010 #15
    I read somewhere that there may be some Darwinian Nature to particles and that the Universe we exist in is more conducive to "matter" as we know it rather than "anti-matter." In some other Universe "anti-matter" may be the norm based on the conditions of the Universe, I can't recall the exact text but if I find it I will post the link. I just posted as thought for discussion. What the mechanism is that decides whether matter or anti-matter is the predominant substance of the Universe is not explained.
  17. May 27, 2010 #16
    The OP's original idea isn't as wacky as the rest here have treated it.

    Here's one thought - At the Big Bang, matter and antimatter were produced in equal quantities, but since antimatter's "arrow of time" points the other way, it went backwards in time and there exists a mirror universe made up entirely of antimatter existing on the other side of T=0.

    Another possibility is that gravity is attractive for matter and repulsive for antimatter. At the Big Bang, gravity slowed the matter down, but accelerated the antimatter. After 14 billion years of acceleration, antimatter is going very close to the speed of light, expanding as a thin shell at the outer edge of our universe.

    The point that I find interesting, that nobody seems to consider, is that those particle-antiparticle pairs would be entangled, in the quantum entanglement sense. Wouldn't that imply that we're only real because our antiparticle pairs are being observed from outside our universe?
  18. May 27, 2010 #17


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    A nice experiment would be to start with a blackbody cavity at above 15 trillion degrees and cool it to below about 5 trillion in a microsec or so. Then check if there is an excess of neutrons (of perhaps ~one per 4 billion photons). It's not absolutely certain that this excess is impossible.

    Unfortunately the experiment would be extraordinarily difficult because many of the pair production antineutrons would hit the walls of the container, automatically leading to a neutron excess of > ~1/10 and swamping the signal.
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