According to the prevailing standard cosmological model, the universe is composed of 5% ordinary matter, 27% dark matter and 68% dark energy. Unfortunately, little understanding exists of the nature of either dark matter or dark energy, which form 95% of the total mass-energy content of the universe. It will be indicated that an understanding of both dark matter and dark energy, associated with the very large universe, may be achieved by consideration of the very small - the quantum theory of particle physics.
First, I shall describe the notions of both dark matter and dark energy.
Second, I shall discuss briefly both the Standard Model (SM) and the Generation Model (GM) of particle physics, indicating the shortcoming of the SM based upon several dubious assumptions and the need for an improved model such as the GM in which the elementary particles of the SM have substructure. This substructure of leptons and quarks leads to new paradigms for both mass and gravity. Finally, I shall show how a new theory of gravity, based on the GM, provides an understanding of both dark matter and dark energy.