After hearing the mangling of cosmology in many episodes, I had to respond to this one.
Bob describes "the Big Bang" as "a titanic space-time explosion" that "has successfully explained a lot of observed phenomena". This is simply not correct.
What we have come to know as the Big Bang theory does not actually include what we might call a Big Bang event. The theory is about the expansion of spacetime over the history of the universe, but it assumes initial conditions. While we can take this model and extrapolate backwards from these initial conditions, we reach beyond trusted physics and, with some additional assumptions, we reach a singularity, a place in the mathematics of our theory where we do not have an adequate physical description of the relevant system. It should be noted that none of the successes of contemporary cosmology lie in the use of this singularity.
For many years, opponents of the Big Bang theory have attempted to saddle the theory with this singularity as part of attempts to discredit the theory. It is unfortunate that those with a new model to propose are jumping on this bandwagon. I suspect that this language attracts the attention of many in the popular science press, but I feel it contributes to misinformation about cosmology. (Much like the jump to the term "dark energy" by researchers at the end of the 90s.)
In the defense of your podcast, however, you did point to the likely fatal problem with Shu's work: it cannot fully account for the background radiation. This is a very serious problem. The current standard cosmological model can not only incorporate the type Ia supernovae observations, it also uses them to make measurements of dark energy density that are backed up by independent measurements of dark energy density from the details of the background radiation. Shu's model has to meet a high bar: it not only has to produce a background radiation, it also has to show why it should fool us into measuring an amount of dark energy consistent with that measured from the type Ia supernovae. (If it can do this, then we can move on to a number of other independent tests with matching measurement results that the standard cosmological model fits quite well.)
Select ReferencesFor information on the basics of the standard cosmological model, I recommend Chapter 1 of PJE Peebles,
Principles of Physical Cosmology. A briefer and somewhat more widely accessible source is the still excellent Nature review article by Peebles, Schramm, Turner, and Kron, "The case for the relativistic hot Big Bang cosmology" (Vol. 352, 29 Aug 1991; also:
http://adsabs.harvard.edu/abs/1991Natur.352..769P ).
The history of cosmology, along with the history of the "Big Bang" term are given a thorough account in Helge Cragh,
Cosmology and Controversy.
The power of using both the supernovae observations and the background radiation observations is discussed in the epilogue to the revised edition of Robert Kirshnmer's book,
The Extravagant Universe. (The book is a great history of the recent supernovae observations.)
