Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Dark energy + missing antimatter

  1. Jul 23, 2004 #1
    dark energy + "missing" antimatter

    Did dark energy stop antimatter from being produced in the early universe
    and is this why there is not much antimatter around today?
  2. jcsd
  3. Jul 23, 2004 #2
    no, antimatter was stopped from being produced because, at the beggining of the early universe, there were 1000 antimatter particles, for ever 1001 matter particles. They all canceled each other out, and matter obviously won.. that is the leading hypothesis i believe..
  4. Jul 23, 2004 #3
    if so where did the missing energy go from the 1000 particals canceled out by each other??
    wouldnot the energy recondence into a 50/50 normal vs antimater state

    second question can neutron be anti matter, will it react with a normal matter
    do all things have anti matter twins ??? photons, or other bits without charge
    would an anti matter sun put out normal photons
  5. Jul 23, 2004 #4
    Yes neutrons have antiparticles too.
  6. Jul 23, 2004 #5


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Yes, this went on until the resulting annihilation energy was insufficient to create matter/anti-matter pairs; crudely, what was 'left' was photons, which collided vigourously with the (largely) protons and electrons (and some alpha particles) until the universe cooled sufficiently that the p and e could form H atoms. At this time, matter and radiation 'decoupled', forming 'the surface of last scattering', whose vastly redshifted (z > 1000) photons we detect today as the CMBR.
  7. Jul 23, 2004 #6
    hope this answers the quest.

    When the Matter and the antimatter was canceling each other out, the extra one particle of matter, survived (1000 AM vs. 1001 M particles) THe rest were all "destroyed" i believe, but there were so many matter particles, which weren't cancelled out, that we have a universe off of them today.
  8. Jul 29, 2004 #7
    That is the most comical hypothesis I have ever heard :biggrin: Somehow, it seems all too easy to be true, but that doesn't necessarily mean it isn't.
  9. Jul 29, 2004 #8
    For an easy to understand explaination of anti-matter and how it came to exist, read "Angels and Demons" by Dan Brown :wink: It's a great book. Meanwhile, I found something that might be of interest. The contents of this site is posted below...

    Particles which are identical to ordinary particles such as protons, electrons and neutrons in every way except one. The antiparticle of the electron, called the positron, has the same cloud-like nature as the electron and same mass, but has a positive electric charge. The antiproton has the same mass as the proton but carries a negative charge. The antineutron has opposite magnetic moment to a neutron.
    We never meet these antimatter particles in normal life, and that is a good thing, because when matter meets antimatter they annihilate each other and their matter energy is changed into radiation. Antiparticles are real, however, and can be made in high energy particle accelerators.

    Some people believe that some regions of the Universe may be made of antimatter. Perhaps whole galaxies might be made of antimatter, separated from normal matter galaxies by vast oceans of empty space? Based on our current understanding of the early events in the Universe, this seems very unlikely. Particles and antiparticles were created close together in the young Universe. Nobody has yet thought of a way they could have been separated into different galaxies.

    If a space ship came to Earth from some distant galaxy we would not be able to tell whether it was made of antimatter just by looking at it since matter and antimatter look the same. But if it was antimatter it would explode when it tried to land!

    By adding a positron to an antiproton it is possible to make an antiatom of hydrogen. This was first achieved in 1995 at the European Laboratory for Particle Physics (CERN) by firing antiprotons through a xenon gas jet. Some of the antiprotons hit protons in the xenon nuclei, creating pairs of electrons and positrons. A few of these positrons then stuck to the antiprotons to form antihydrogen.

    Antiatoms do not last very long on Earth. Each antiatom produced at CERN survived for only about forty-billionths of a second before it met ordinary matter and changed into gamma radiation.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Dark energy + missing antimatter
  1. Missing stuff (Replies: 97)

  2. Missing galaxies? (Replies: 11)

  3. Missing Matter? (Replies: 2)