Big science news today: the Planck experiment has released a huge raft of results based on cosmological observations made during 2009-10. Planck is a satellite-based experiment that has been making precision measurements of the cosmic microwave background (CMB) radiation, the details of which tell us a great deal about the history and structure of the universe. Planck is a truly spectacular project.
I remember that when I was an undergraduate physics student — which was quite a long time ago now — we heard rumours of this satellite, which was then in the planning stages. The hope was that it, and to a lesser extent its predecessor WMAP, would usher in an era of “precision cosmology”, in which cosmologists would have a wealth of high quality measurements against which to judge their theories about cosmic structure and evolution.
Based on the results published today, I would say that those hopes have been triumphantly vindicated. For instance, consider this paper on cosmological parameters; look at Tables 1 and 2. These are amazing results: baryon density is about 2.2%, cold dark matter density about 12%, dark energy density about 68%, Hubble constant about 67, and the age of the universe about 13.8 billion years (with an uncertainty of only about 100 million years!).
There is a lot here for non-specialists to digest — and I certainly count myself in that group. The BBC is on the case.