The Scales of Things

• atom made of  +nucleus and -electrons held together by electromagnetism
• nucleus made of protons and neutrons held together by strong force (and sometimes, broken apart by the weak force)
• protons and neutrons made of quarks held together by gluons
• quarks made of ???  held together by ???
• • possible that they have no size at all

  • possible that they are not fundamental composites of more fundamental particles

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