No "explosion" in Big Bang cosmology

ALEJANDRO GANGUI

UNESCO, París, Francia

Simposio; International Astronomical Union - Symposium 260: The Rôle of Astronomy in Society and Culture; 2009

International Astronomical Union (IAU)

Common wisdom says that cosmologists are smart: they have developed a theory that can explain the "origin of the universe". Every time an astro-related, heavily funded "big-science" project comes to the media, naturally the question arises: will science -through this or that experiment- explain the origin of the cosmos? Can this be done with the LHC, for example? Will this dream machine create other universes?Of course, the very words we employ in cosmology reinforce this misconception: so Big Bang must be associated with an "explosion", even if a "peculiar" one, as it took place nowhere (there was presumably no space before the beginning) and happened virtually in no time (supposedly, space-time was created on this peculiar -singular- event). Right, the thing sounds confusing. Let us imagine what kids may get out of all this.We have recently presented a series of brief astronomy and cosmology books aimed at helping both kids and their teachers in these and other arcane subjects, all introduced with carefully chosen words and images that young children can understand (*). In particular, Volume Four deals with the Big Bang and emphasizes the notion of "evolution" as opposed to the -wrong- notion of "origin" behind the scientific model. We then explain some of the pillars of Big Bang cosmology: the expansion of space that drags away distant galaxies, as seen in the redshift of their emitted light; the build-up of light elements in a cooling bath of radiation, as explained by primordial nucleosynthesis; and the existence and main features of the ubiquitous cosmic microwave background radiation, where theory and observations agree to a highly satisfactory degree.Of course, one cannot attempt to answer the "origins" question when it is well known that all theories so far break down close to this origin (if there was actually an origin). It is through observations, analyses, lively discussions and recognition of the basic limitations of current theories and ideas, that we are led to try and reconstruct the past and predict the future evolution of our universe. Just that. Sound science turns out to be much more attractive when we tell the truth of what we really know.(*) http://www.google.com/search?q="queres+saber"+gangui