A New Measurement of the Expansion Rate of the Universe – Adam Riess

Here’s a nice talk by Nobel Laureate Adam Riess delivered on May 11th at the Harvard-Smithsonian Centre Center for Astrophysics and is now available for you to watch at your leisure. It’s an hour long, but well worth watching if you’re interested in cosmology in general and in apparent tension between different determinations of the Hubble constant in particular.

Here’s the description of the talk, which is introduced first by Bach and Daniel Eisenstein:

The Hubble constant remains one of the most important parameters in the cosmological model, setting the size and age scales of the Universe. Present uncertainties in the cosmological model including the nature of dark energy, the properties of neutrinos and the scale of departures from flat geometry can be constrained by measurements of the Hubble constant made to higher precision than was possible with the first generations of Hubble Telescope instruments. A streamlined distance ladder constructed from infrared observations of Cepheids and type Ia supernovae with ruthless attention paid to systematics now provide 2.4% precision and offer the means to do much better. By steadily improving the precision and accuracy of the Hubble constant, we now see evidence for significant deviations from the standard model, referred to as LambdaCDM, and thus the exciting chance, if true, of discovering new fundamental physics such as exotic dark energy, a new relativistic particle, or a small curvature to name a few possibilities. I will review recent and expected progress.

And here’s the talk in full.

After watching the video you be interested in voting in my totally unscientific poll on the matter:

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