Planck data released

Today some of the Oskar Klein Centre’s researchers were viewing the webcast from the data realease of the Planck satellite.

Planck webcast
OKC researchers digesting the new Planck data.

The Planck data is a very impressive set, which will be used extensively in cosmological analyses for many years to come. It will take time to digest all the information in the 29 scientific papers that were also put online today, on Planck Published Papers.

It seems the major features of the LambdaCDM model have been verified, in addition the data can not accomodate a fourth, hypothetical neutrino. The most significant new result is a markedly lower value for the expansion rate (the “Hubble constant”) which in turn influences the estimates of the energy density of the universe in terms of dark matter, ordinary matter, and dark energy, by up to 20 percent.

The only anomaly which was reported during the press conference is a strange undershoot of the angular power spectrum at the 10-degree scale. This seems only to be at the 2.5 – 3 sigma level, and we were a bit surprised that they made such a relatively big deal of it. Of course, it would be very interesting if true (see for example a paper I wrote with Ulf Danielsson, Uppsala University, in 2002 on transplanckian physics that could be at play, paper). However, we should cautiously wait for next year’s added data (including polarization)  to make a safer evaluation of the significance of this anomaly.

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