For the first time, researchers have seen how light behaves during a mysterious phenomenon called ‘imaginary time’

When you shine light through almost any transparent material, the gridlock of electromagnetic fields that make up the atomic alleys and side streets will add a significant amount of time to each photon’s commute.

This delay can tell physicists a lot about how light scatters, revealing details about the matrix of material the photons must navigate. Yet until now, one trick up the theorist’s sleeve for measuring light’s journey – invoking imaginary time – has not been fully understood in practical terms.