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Can neutrons collide?

  1. Sep 23, 2009 #1
    Sorry, this is probably a dumb question but I am new to physics so forgive my ignorance. I learned in class that when a person touches something, or any two objects touch each other for that matter, the force interaction is actually due to the electrons repelling each other. So I wondered what would happen if two particles with no charge (such as neutrons) collided. Would they actually collide without having opposite forces interacting? Would they pass through each other? It makes me wonder what matter actually is if there is no collision. I asked my professor this question but he didn't have an answer. Any help would be appreciated.
  2. jcsd
  3. Sep 24, 2009 #2
    look up 'neutron star' and 'degenerate matter'.
  4. Sep 24, 2009 #3


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    Colliding neutrons would scatter. However, the cross-section or probability of such a reaction would be very small, and each neutron would be more likely to collide with an atomic nucleus and be absorbed. Otherwise a free neutron will eventually decay.

    Stellar environments like a neutron star are well beyond our experience and capabilities on earth (manmade) systems.
  5. Sep 24, 2009 #4


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    There are forces between two neutrons besides the Coulomb force. They have magnetic moments, so there is a magnetic force between them, similar to the force between two compass needles. There is also a "nuclear force between them when they get within about 1 fm of each other. This nuclear force is what holds nuclei together.
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