≡ Menu

Why There’s More Matter Than Antimatter in the Universe

KEK accelerator. Image credit: KEK
In the first few moments of the Universe, enormous amounts of both matter and antimatter were created, and then moments later combined and annihilated generating the energy that drove the expansion of the Universe. But for some reason, there was an infinitesimal amount more matter than anti matter. Everything that we see today was that tiny fraction of matter that remained.

But why? Why was there more matter than antimatter right after the Big Bang? Researchers from the University of Melbourne think they might have an insight.

Just to give you an idea of the scale of the mystery facing researchers, here’s Associate Professor Martin Sevior of the University of Melborne’s School of Physics:

“Our universe is made up almost completely of matter. While we’re entirely used to this idea, this does not agree with our ideas of how mass and energy interact. According to these theories there should not be enough mass to enable the formation of stars and hence life.”

“In our standard model of particle physics, matter and antimatter are almost identical. Accordingly as they mix in the early universe they annihilate one another leaving very little to form stars and galaxies. The model does not come close to explaining the difference between matter and antimatter we see in the nature. The imbalance is a trillion times bigger than the model predicts.”

If the model predicts that matter and antimatter should have completely annihilated one another, why is there something, and not nothing?

The researchers have been using the KEK particle accelerator in Japan to create special particles called B-mesons. And it’s these particles which might provide the answer.

Mesons are particles which are made up of one quark, and one antiquark. They’re bound together by the strong nuclear force, and orbit one another, like the Earth and the moon. Because of quantum mechanics, the quark and antiquark can only orbit each other in very specific ways depending on the mass of the particles.

A B-meson is a particularly heavy particle, with more than 5 times the mass of a proton, due almost entirely to the mass of the B-quark. And it’s these B-mesons which require the most powerful particle accelerators to generate them.

In the KEK accelerator, the researchers were able to create both regular matter B-mesons and anti-B-mesons, and watch how they decayed.

“We looked at how the B-mesons decay as opposed to how the anti-B-mesons decay. What we find is that there are small differences in these processes. While most of our measurements confirm predictions of the Standard Model of Particle Physics, this new result appears to be in disagreement.”

In the first few moments of the Universe, the anti-B-mesons might have decayed differently than their regular matter counterparts. By the time all the annihilations were complete, there was still enough matter left over to give us all the stars, planets and galaxies we see today.

Original Source: University of Melbourne News Release


Fraser Cain is the publisher of Universe Today. He's also the co-host of Astronomy Cast with Dr. Pamela Gay.

Comments on this entry are closed.

  • Peter K March 31, 2008, 7:53 AM

    Cheers, you might have noticed somewhere along the way, that Ian’s articles are a simplification of the original text? Hmmm??
    If you want to know more, there’s more out there, but these are written for fools like me who are interested but not scientifically minded enough to appreciate the math and the specific jargon.
    I got the basic idea and now have an idea why the universe might be more matter than anti. In my mind: good article.

  • Billy March 31, 2008, 8:41 AM

    Nate: We’re just following orders to tend to, and name, the Universe. See Genesis 2:19 and 2:20.

    If God didn’t intend for us to inquire, why bother giving us a brain or freewill.

  • God March 31, 2008, 1:48 PM

    It’s a pity that my fans think I am a concerning invisible wizard with a plan because of some badly quoted anecdotes from the stone age, mixed with some common knowledge and wisdom. Seen everywhere around the globe.

    Nate and co. Abandon believing in invisible things which only become visible if you have faith and follow strict faith rules that claim goddidit. Religion is delusion and blind acceptance of wild anecdotes and biased interpretations. Science is not. It is based on objective observation, worldwide skepticism and absolute freedom of thought. The odd thing is that nobody ever comes up with a goddidit hypothesis. That means there must be more plausible, simple and logical explanations. Invoking invisible wizards from the bronze age is overkill.

  • Byson March 31, 2008, 4:45 PM

    “God created us so that we might bring honor and glory to Him”

    What a pathetic creature this god must be! So insecure that he creates an entire universe simply to glorify himself! Any creature who would command another sentient being to worship him or else is no more than a bully and deserves no more respect. You should remember this site is devoted to science and should not be used as a soapbox for your pathetic beliefs. Read your book of lies and grovel before your make believe god if you must but kindly shut your mouth and keep your beliefs to yourself.

  • Joel April 1, 2008, 7:45 AM

    Nate: by the COINCIDENCE of one sperm succeeding to fertilize the egg while MILLIONS of others failed…we at universe today have to deal with one of the ironies of that race; a BELIEVER named NATE whose answer to EVERYTHING is the trite and hackneyed refrain “god did it.”

    Answer me this Nate:

    Did your god predetermine which sperm would win the race up your momma’s vagina?

    Or did your god cause all the sperm to line up at the ejaculatory starting line and then let them race( with the fittest and luckiest succeeding)?

    Why did your god not DESIGN ONE SPERM that always worked, that always fertilized the egg?

    In other words, why the race? Why the waste?

    Why the WASTE of millions of sperm cells, when one INTELLIGENTLY DESIGNED sperm could be DESIGNED( by an omnipotent omniscient creator) to ALWAYS do the job?


    WHY—it sounds a lot more like evolution at work—randomly, coincidentlay throwing a lot of possibilities in an environment—


    Now extrapolate from the sperm cell level to the cosmic level…

  • Joel April 1, 2008, 7:57 AM

    Nate :

    just that


    ..and NOTHING more~~~

  • Joel April 1, 2008, 8:15 AM

    NATE: This is not the appropriate forum for this, but ponder you the following:
    Why is your Bibl;e-based BELIEF any more REAL, any more substantive than the theistic BELIEFS of the ancient Aztecs’,Mayans’ or Incans’?

    Why is your BELIEF any more real or substantive than the theistic BELIEFS of the ancient Greeks’, Romans’, Egyptians’.

    The answer:
    merely because you are EXTANT today and
    MERELY because you BELIEVE it~~~only this and NOTHING MORE!

  • Nate April 1, 2008, 3:36 PM

    I understand the point of view that you all come from. I understand that this is not the BEST place to be having these type of conversations, but I thought it necessary. In respect of the forum I will get off and leave it alone. Dont bother writing back I wont check the entrys.
    I’m not giving up. I could (and probibly will) write on other pages of this site.
    I have learned lots form your entrys.
    I’m praying for you all, whether you like it or not :)

  • vidyardhi nanduri April 14, 2008, 8:30 PM

    From Highvoltage to Particle-Physics-Planck Scale and a lot more touching -Nature,Creation- This is a very interesting discussion.
    Why not search origins to remove the cob-webs ?
    Why not search Cosmic Function of the Universe?
    Why not Define Cosmology?
    A search from the Center of the Universe forms the HEART OF COSMOLOGY for
    Scientists and Philosophers. Nature provides a Solution-
    Intellectual enlightened Spirit to understand the Mysterious Functions with a Comprehension.See my books for orderly growth of this subject and welcome interaction

  • hellojoe June 30, 2008, 12:14 PM

    did everyone really stop talking when this nate guy left, i liked this topic and then like always it turned into an argument not a discussion…the only thing keeping you people coming back to talk was the insult nate and after then u just stopped posting stuff, all u people really care about is proving your pathetic little selves right and not even considering anything else, anyways does anti matter create electric fields acording to its charge just like a moving electron, for example would moving positrons create the same electric field as electrons?

  • markus nell December 11, 2008, 1:47 PM

    I loved the info I just wish there was more

    I’m like 16 jeers old and I don’t understand really anything about the creation of the universe and how particles and atoms work and I’m not to shore about anti mater but I had one day sum sort of crazy theory what if their is sum sort of neutral mater like the nucleus of a atom that ceeps the antimater and the mater apart from each uther like sum sort of glue I have bin wandering about this for sum time so even when this is sum sort of crazy idea
    Plz reply on this idea so that I can stop wandering about it