Institute for Advanced Study / Princeton University Joint Astrophysics Colloquium

The standard model of cosmology has passed every test over the last twenty years. Yet it remains unsatisfactory, with 95% of the universe being dark components, whose nature we did not understand. Now, there are possible ‘cracks’ in the model, as recent observations of the local expansion rate of the universe, parameterized by the Hubble constant, do not match predictions using data from the Cosmic Microwave Background and our standard model. This is the best end-to-end test of our cosmological model, and currently, we do not pass the test. I will discuss my team’s Pantheon+SH0ES measurements on the local side, and review the numerous crosschecks and tests on our data and analysis. I will show new data from the James Webb Space Telescope and explain how it strengthens the current tension. Finally, I will talk about how the community is moving forward, with different probes of the early and late universe, and what new theoretical ideas show the most promise.