The Lingering Hubble Tension and New Puzzling Measurements of Dark Energy

Speaker: Daniel Scolnic (Duke University) In Person and zoom

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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 also talk about new measurements of dark energy from the Dark Energy Survey, and compare them to other measurements and discuss implications about a possible evolution of dark energy.  Finally, I will go over the upcoming LSST and Roman surveys and talk about how they can help answer these increasingly puzzling issues.