When: Wednesday, October 25, 2023, 4:30 PM - 6:00 PMWhere: Physics (G. O. Jones building) Room 516, Mile End
Speaker: Roy Maartens (UWC)
Tensions in the observed values of the Hubble constant and other key parameters of the concordance model of cosmology may indicate problems in the model itself. This motivates further independent tests of the model. I will describe a test of a key foundation of the concordance model - the Cosmological Principle. According to the Cosmological Principle, the Universe should be statistically isotropic. In particular, isotropy in the CMB must be consistent with isotropy in the galaxy distribution. This means that the dipole in the CMB due to the observer's motion should agree in direction and amplitude with the dipole in the galaxy distribution. Current results suggest that there is a significant tension between the amplitudes of these dipoles. I will discuss some theoretical issues that remain to be clarified before this can be declared as a new tension.