The science of cosmology has been very successful in explaining a wide range of observational evidence about the Universe, from the detailed properties of the cosmic microwave background radiation to the distributions of galaxies, and the elemental abundances in astrophysical environments. However, there are several major unknowns in cosmological theory, including the nature of dark matter and dark energy. These gaps in knowledge are frustrating for anyone who would like to understand the nature of the Universe. In this free course, Unsolved problems in cosmology, you will learn about what the current unsolved problems are and about the possible ways in which they may be solved in the future.