Slow light

Not the kind explored here by Radiolab but the 'normal' kind:



Remember, however, that from the point of view of a photon, whether from the Sun or the Andromeda galaxy, what we perceive as the distance to any object is traversed instantaneously. As Jim Al Khalili puts it:

For a particle of light, time stands still, such that the past, the present and future all collapse into one eternal moment.