1.) How did the Universe begin? What “type” of inflation occurred? What preceded and/or caused inflation? 2.) What explains neutrino mass? Are neutrinos Dirac or Majorana particles? Are there heavy, sterile neutrino species? 3.) Why is our Universe matter-dominated? More matter than antimatter permeates the Universe. 4.) What is dark matter? Its effects are understood, not its underlying cause. 5.) What is dark energy? Its properties indicate a constant, positive spatial energy density.
