Thursday, October 3, 2019, 16:00
Ido Ben-Dayan, Ariel University
The expansion rate of the Universe dubbed "Hubble parameter" or "Hubble constant" is the most important Cosmology discovery ever made, and is the cornerstone of Modern Cosmology. The existence of an expansion forces the Universe as a whole object to have dynamics. I will start with a recap of the history of Hubble parameter measurements in the last 100 years. I will then describe two of the most common practices of determining the Hubble parameter today - CMB observations and Type Ia supernovae. These two measurements, sometimes along with other probes, are in disagreement with a growing level of significance in the past decade, leading to the "Hubble tension". Taken at face value, this tension is the most promising signal of New Physics that deviates from the Concordance or LCDM Model of Cosmology. I will discuss some possibilities of resolving the tension either via systematics or New Physics.