A timeline of the universe’s expansion since the big bang (Image: NASA)

TWICE in the past week I have been confronted in debates with the question that Thomas Aquinas and others have used in a theological context: “Why is there something rather than nothing?”

I don’t want to dwell on whether this justifies the existence of God. Rather, I’d like to point out that physics has largely answered this question, at least if it is reframed as “how” rather than “why”.

A three-dimensional space can be geometrically open, closed or “flat”, and my scientific career was launched largely by a …