Hubble Constant

In an almost zero-research day, Wendy Freedman (OCIW) gave a great and inspiring talk about measuring the Hubble Constant with local measurements of Cepheid stars and supernovae. She demonstrated the great value of moving to infrared observations and argued convincingly that systematic uncertainties in the measurements are now down around the few-percent level. Of course the interesting thing is that these local measurements consistently get Hubble Constants a tiny bit higher (Universe a tiny bit smaller or younger) than the cosmic-microwave-background-based inferences. Freedman argued strongly that this tension should be pursued and tested, because (a) it provides a fundamental, independent test of the cosmological model, and (b) it could conceivably point to new physics. I agree.

1 comment:

  1. Why the new physics stuff? Back when the two Hubble-constant camps differed by a factor of 2 or more, no-one claimed it might indicate new physics. Now, they differ by a few per cent, and several people mention new physics.