“Understanding the Accelerating Expansion of the Universe and the Hubble Tension” with Dan Scolnic (Duke University, USA)

In this last year, the Pantheon+ and SH0ES teams released likely our last measurements of the expansion history of the universe.  On one hand, constraints from Pantheon+ show a universe consistent with the Lambda-CDM model, where dark energy can be described by a cosmological constant.  On the other hand, constraints combining Pantheon+SHOES data find a high value of the Hubble constant, now 5sigma away from the value inferred using Lambda-CDM from measurements of the Cosmic Microwave Background.  How can both these statements be true? In this talk, the speaker goes over these separate but overlapping measurements, and discussess how we can have tensions with some parts of the cosmological model but not others. The speaker discusses possible explanations to the Hubble tension, and goes over how other tensions have arisen in cosmology. Finally, the speaker talks about how new telescopes, like the James Webb Space Telescope, can help resolve these controversies.

Dan Scolnic received his B.S from MIT in 2007, his PhD from Johns Hopkins in 2013, and then received a Hubble fellowship and KICP fellowship to do his postdoc at UChicago. Dan then became a professor at Duke University where he has gotten the chance to start Duke’s cosmology program. In the last few years, he has won a Packard Fellowship, Sloan Fellowship, and Department of Energy Early Career Award.

Webinar was recorded on November 10, 2022