Unsolved Problems for the 21st Century
    
    Force	Particle	Range	Interaction	Effect
    
    Strong	Gluon	Short	Quarks	Binds quarks together
    Electromagnetic	Photon	Infinite	Electrons	Transfers energy from place to place
    Weak	W+,W-,Z0	Short	Leptons	Governs Radioactive Decay
    Gravitational1	Higgs Boson	Short	All Massive Particles	Confers mass to particles
    Gravitational2	Graviton	Infinite	All Massive Particles	Conveys Gravitational Attraction
    
    What is the nature of the Higgs Boson?
    
    Where is the missing matter in the universe?
    
    Speculation: Can the graviton's effect be shielded?
    
    Physics (the short version):