A different approach to cosmology

TLDR: In this article, the authors used time reversal and elementary logic to conclude that the universe must originally have been so compact that we can talk of a beginning, which they called the primeval atom.

Abstract: Modern cosmology began with the solutions to Einstein's theory of gravity discovered by Aleksandr Friedmann and Georges Lemaitre in the 1920s. When combined with the Hubble redshift‐distance relation, these solutions could be interpreted as showing that we live in an expanding universe. By 1930, the scientific establishment and much of the lay public believed in this expanding cosmos. It then requires only time reversal and elementary logic to conclude that the universe must originally have been so compact that we can talk of a beginning. Lemaitre tried to describe this state as the “primeval atom.”