'Insect-eye' compass can navigate by the sun even on a cloudy day

A compass that relies on polarised light can use the sun to tell where magnetic north is, even when it is cloudy. It is based on how some insects navigate and could be used when conventional magnetic compasses aren't reliable, such as on robotic drones. Insects like ants and bees can sense direction using sunlight's intensity and its polarisation, a measure of how light rays can appear twisted, through specially adapted receptors arranged in a ring in their…