ΛCDM: Much More Than We Expected, but Now Less Than What We Want

The Λ CDM cosmological model is remarkable: with just six 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 Λ CDM involves physics beyond the standard model of particle physics: particle dark matter, dark energy and cosmic inflation. Until this ‘new physics’ is clarified, Λ 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.