21st Century Cosmological Tensions that have Emerged from Precision Measurements from Space Telescopes

In the past decade, a number of tensions have arrisen between observational data in the nearby Universe and the standard cosmological model, Lambda-Cold Dark Matter (LCDM) as resulting from fits to anisotropies in the Cosmic Microwave Background. Two primary tensions are present: (1) a tension in the value of the Hubble Constant (the current expansion rate of the Universe), and (2) a tension in the sigma-8 parameter (the local clustering of matter at 8 Mpc scales). In both cases, the tensions are well-constrained by multiple, independent measurements produced by multiple teams using multiple datasets from ground and space. In this presentation, I will introduce these tensions with a focus on the current observational data and the unique space-based instrumentation that enabled them. I will higlight some of the puzzles that the two tensions pose for constructing theoretical cosmological models and the insights into the dark sector that could be gained by resolving the tensions. As will be apparent in the presentation, the key for obtaining astophysical measurements at this level of precision has been the use of space-based instrumentation -- whether to measure the Cosmic Microwave Background with COBE or WMAP or to use standard candles to measure distances with the Hubble Space Telescope and now the James Webb Space Telescope. Thus, I will conclude by looking to the future of cosmological measurements enabled by the Nancy Grace Roman Space Telescope and mention ways to get involved in its transformative science.