$\Lambda$CDM: Much more than we expected, but now less than what we want

Abstract

The $\mathrm{\Lambda }$CDM cosmological model is remarkable: with just 6 parameters it describes the evolution of the Universe from a very early time when all structures were quantum fluctuations on subatomic scales to the present, and it is consistent with a wealth of high-precision data, both laboratory measurements and astronomical observations. However, the foundation of $\mathrm{\Lambda }$CDM involves physics beyond the standard model of particle physics: particle dark matter, dark energy and cosmic inflation. Until this `new physics' is clarified, $\mathrm{\Lambda }$CDM is at best incomplete and at worst a phenomenological construct that accommodates the data. I discuss the path forward, which involves both discovery and disruption, some grand challenges and finally the limits of scientific cosmology.

Proceedings of the Lemaitre Workshop on Black Holes, Gravitational Waves and Space Time Singularities, published in Foundations of Physics (2018)