Seminar Speaker Thomas Tram Department of Physics and Astronomy, Aarhus University, Denmark Title How fast is the Universe really expanding? Abstract The current expansion-rate of the Universe is called the Hubble constant. This parameter can be measured in the local Universe by different types of observations, but it may also be inferred from the Cosmic Microwave Background (CMB) anisotropies. However, the value inferred from the CMB is significantly smaller than the one inferred from direct observations in the local Universe. This discrepancy is approaching the 5-sigma mark, so what is going on here? This problem is a hot topic in cosmology, and I will first explain why such a discrepancy is not necessarily due to a systematic error in the experiments themselves but could also be a hint of new physics. Then I will give some examples of what this new physics could (not) be and describe a class of very interesting models that my research team will investigate in the next few years. Questions from 11-11.15 Join Zoom Meeting https://aarhusuniversity.zoom.us/j/67486435509 Meeting ID: 674 8643 5509 Join by SIP 67486435509@109.105.112.236<mailto:67486435509@109.105.112.236> 67486435509@109.105.112.235<mailto:67486435509@109.105.112.235> Join by H.323 109.105.112.236 109.105.112.235 Meeting ID: 674 8643 5509