It’s a familiar observation that stargazing is a way of seeing into the distant past, but pondering it can still be a stunning mental exercise. In this brief animation from Nature, the US astrophysicist and Nobel Prize-winner Saul Perlmutter imagines the journey of a single photon that’s been hurtling through space for some 10 billion years until it reaches a giant telescope on Earth. Describing the photon’s journey in relation to the chronology of our planet’s development and the evolution of life, Perlmutter evokes not only the vastness of the Universe but also the rather remarkable way that scientists have been able to measure it.