Shortly after dawn, the sky swirled with the pink remnants of Hurricane Odile as Father Paul Gabor, S.J., and I headed east from Tucson along Interstate 10. Our journey, first to Safford and then up to the Mount Graham International Observatory, was a modest drive but also a road trip into the universe.

An astrophysicist and Jesuit priest, Gabor serves as vice director for the Vatican Observatory Research Group, which operates the Vatican Advanced Technology Telescope (VATT) on Mount Graham. This immediately brings up two questions: Why does the Vatican have an observatory? And what is that observatory doing in Arizona?

Gabor, I quickly discovered, is a fine traveling companion, his reserve balanced by a dry, mischievous wit. That said, I admit to being overmatched: Raised in the former Czechoslovakia, Gabor holds multiple advanced degrees, from astrophysics to divinity. He speaks eight languages, six fluently. As for me, I’m neither especially religious nor adept at the physical sciences, having pulled a C in college astronomy — a fact I confessed to Gabor early...