The BBC, the Big Bang and WMAP

For some reason, the BBC’s Today Program had a feature on the Big Bang and its purported problems confronting modern data. Apart from the woefully misguided Eric Lerner, the discussion was relatively nuanced and at least attempted to distinguish between a wrong theory and an incomplete one — the questions that the Big Bang, as it stands today, leaves unanswered. The Big Bang per se is simply the idea that the Universe started out hot and dense and has been expanding ever since. This is borne out in great detail by observations such as the expansion of the Universe itself; by the abundances of the light elements like Hydrogen and Helium which were “cooked” in the heat of the Universe when it was just a few minutes old; and by the Cosmic Microwave Background which I spend much of my time investigating, the so-called afterglow of the Big Bang (see the picture below).

The unanswered questions are addressed in refinements to the Big Bang such as the ΛCDM model, which posits the properties of the particles and energy that make up of the bulk of the Universe: CDM is “cold dark matter” which we’ve only observed via its gravitational effects, but haven’t yet seen the requisite particle in the laboratory; Λ — or “dark energy” — is something like Einstein’s famous Cosmological Constant which seems to be driving the universe to expand ever faster, and whose identity is completely mysterious — and even worrying. (This is the explanation for Tom Shanks’ experts-only quip of a few weeks ago.)


The feature also included a brief statement from my colleague Kate Land, who has been working with Joao Magueijo (and neither of whom I seem to be able to point to right now) investigating some of the unexpected patterns we see in the CMB, and whose work may point to yet more refinements to or revisions of the Big Bang.

For us experts, the most interesting part of the interview was the statement that we should expect new results from the WMAP satellite in November. WMAP reported its first results back in 2003, and we’ve been waiting for their analysis of yet more data for the past year and a half or so (meanwhile, experiments like Boomerang have continued to analyze their own CMB data).