Question: how did the universe start

Maria McNamara answered on 21 Nov 2019:

Based on available evidence our best hypothesis for the origin of the universe is the big bang theory. All matter was condensed into an infinitely dense and hot singularity, which expanded, forming space. We see evidence of the big bang in the trajectories of galaxies (overall galaxies are moving further away from each other and from us) and in ripples in the fabric of nterstellar matter in space.