Is the ΛCDM model in trouble?

Abstract

ABSTRACT
We’ve known since the late 1920s that the Universe is expanding. However, the expansion rate currently inferred from measurements of the cosmic microwave background now disagrees with that obtained from supernova measurements. Over the past few years, theorists have been exploring the possibility that this Hubble tension is explained by some new “early dark energy”: a new component of matter that may have been dynamically important several hundred thousand years after the Big Bang.

BIO
Marc Kamionkowski is a theoretical physicist. His research is in cosmology, astrophysics, and elementary-particle theory. His main focus has been on particle dark matter, inflation and the cosmic microwave background, and cosmic acceleration. He also worked on neutrino and nuclear physics and astrophysics, large-scale-structure and galaxy formation, intrinsic galaxy alignments and gravitational lensing, gravitational waves, phase transitions in the early Universe, alternative-gravity theories, the first stars and the epoch of reionization, and a bit in stellar and high-energy astrophysics.

Q&A