The plodding photon, or how the speed of light looks sluggish on a galactic scale

According to Albert Einstein’s theory of special relativity, the speed of light (approximately 299,792 kilometres – or roughly 7.5 rotations around the Earth – per second in a vacuum) is the Universe’s speed limit, and therefore the fastest we could ever hope to travel through space. Swift as it might seem, when it comes to traversing the vast expanses between solar systems and galaxies, it’s still very slow-going. Indeed, the nearest galaxy to the Milky Way, Canis Major, is 25,000 light years away. Set to a mesmerising score by the US composer Steve Reich, Riding Light is an illuminating look at light speed, simulating the journey of a photon from the Sun’s surface to just beyond Jupiter’s orbit. For a brisker take, see a condensed, three-minute version of the same video here.