In this talk, I will introduce the inconsistency between the cosmological principle and observations. In reconciling the inconsistency, we propose that the Milky Way could live inside a Gpc-scale local void that forms from the multi-stream inflation, and the existence of a Gpc-scale local void could ease the Hubble tension and explain the cosmic dipole. In this scenario, the Universe is homogeneous and isotropic, but with a number of voids embedded.
Ding Qianhang, a current PhD candidate at the Hong Kong University of Science and Technology and a research assistant at the HKUST Jockey Club (赛马会) Institute for Advanced Study. He focuses on studying the cosmology and high energy physics through the multi-messenger astronomy, especially, including the topics about gravitational wave cosmology, primordial black holes, void cosmology and cosmological collider physics.