When It All Began: Big Bang

What was the Big Bang like? This question puzzled Georges Lemaitre as early as 1931. As an ordained priest (and the professor of astronomy at the Louvain Catholic University in Belgium) the deep origins and creation of the universe had natural fascination to him, though he saw science and faith as separate things. In 1927 in a fine theoretical study, he pointed out the expected redshift in the light of remote galaxies and its dependence on the distance. He talked about l’atome primitif ; it was like a big radioactive nucleus that started to decay. He surmised that “the very origin is not reachable even by thinking, but that one could approach it in some asymptotic way.” At that time most astronomers did not consider it proper even to try think about problems of the first origins. Nowadays, the theoretical study of the initial, very dense matter is a part of cosmology and the observed faint afterglow of the hot Big Bang provides information about the very early Universe.